Human ethology is the study of human behavior.
Ethology as a discipline is generally thought of as a sub-category of biology, though psychological theories have been developed based on ethological ideas (e.g. sociobiology, evolutionary psychology, attachment theory, and theories about human universals
such as gender differences, incest avoidance, mourning, hierarchy and
pursuit of possession). The bridging between biological sciences and
social sciences creates an understanding of human ethology. The International Society for Human Ethology is dedicated to advancing the study and understanding of human ethology.
History
Ethology has its roots in the study of evolution,
especially after evolution's increasing popularity after Darwin's
detailed observations. It became a distinct discipline in the 1930s with
zoologists Konrad Lorenz, Niko Tinbergen and Karl Von Frisch. These three scientists are known as the major contributors to human
ethology. They are also regarded as the fathers or founders of ethology.
Konrad Lorenz and Niko Tinbergen rejected theories that relied on
stimuli and learning alone, and elaborated on concepts that had not been
well understood, such as instinct.
They promoted the theory that evolution had placed within creatures
innate abilities and responses to certain stimuli that advanced the
thriving of the species. Konrad Lorenz also indicated in his earlier
works that animal behavior can be a major reference for human behavior.
He believed that the research and findings of animal behaviors can lead
to findings of human behaviors as well. In 1943, Lorenz devoted much of
his book, Die angeborenen Formen moglicher Erfahrung,
to human behavior. He designated that one of the most important factors
of ethology was testing the hypothesis derived from animal behavioral
studies on human behavioral studies. Due to Lorenz promoting the
similarities between studying animal and human behavior, human ethology
derived from the study of anima behavior. The other founders of ethology, Niko Tinbergen and Karl von Frisch, received a Nobel Prize
in 1973, for their overarching career discoveries concerning
organization and elicitation of individual and social behavior patterns.
Many developmental psychologists
were eager to incorporate ethological principles into their theories as
a way of explaining observable phenomenon in babies that could not
necessarily be explained by learning or other concepts. John Bowlby and Mary Ainsworth used ethology prominently to explain aspects of infant-caretaker attachment theory. Some important attachment concepts related to evolution:
The Attachment has evolved because it promotes the survival of
helpless infants. Primates and other animals reflexively attach
themselves physically to their parent, and have some calls that elicit
parental attention. Human babies have adaptively developed signaling
mechanisms such as crying, babbling, and smiling. These are seen as
innate and not learned behaviors, because even children born blind and
deaf begin to smile socially at 6 weeks, and cry and babble. These
behaviors facilitate contact with the caregiver and increase the
likelihood of infant survival.
Early signaling behaviors and the baby's tendency to look at faces
rather than objects lead to attachment between the caretaker and baby
that solidifies around 6–9 months of age. Bowlby theorized that this
attachment was evolutionarily fundamental to human survival and is the
basis for all relationships, even into adulthood.
Adults are also adaptively bent toward attachment with infants.
Typical "baby-ish" features, such as a large head and eyes in proportion
to the body, and round cheeks, are features that elicit affection in
adults. Many parents also form a "bond" with their newborn baby within
hours of its birth, leading to a deep sense of emotional attachment with
one's own offspring and increased behaviors that promote infant
survival.
Many of Bowlby's early methods relied heavily on ethological observations of children in their natural environments.
In later years, ethology played a large role in sociobiological
theory and ultimately, in evolutionary psychology, which is a relatively
new field of study. Evolutionary psychology combines ethology,
primatology, anthropology, and other fields to study modern human
behavior to adaptive ancestral human behaviors.
View on human nature
Humans
are social animals. Just as wolves and lions create packs or hunting
groups for self-preservation, humans create complex social structures,
including families and nations.
Humans are "biological organisms that have evolved within a particular environmental niche".
Intelligence, language, social attachment, aggression, and altruism
are part of human nature because they "serve or once served a purpose in
the struggle of the species to survive".
Children's developmental level is defined in terms of biologically based behaviors.
Human's needs evolve based on their current environment. Humans must
adapt in order to survive. Cognitive thinking and communication arose
as a result of a need for cooperation amongst individuals for survival.
View on human nature varies across ethological theorists
Lorenz
believed that humans have an automatic, elicited nature of behavior,
such as stimuli that elicit fixed action patterns. His theory
developed from the reflex model and the hydraulic or "flush toilet"
model, which conceptualized behavior patterns of motivation. Certain
fixed action patterns developed out of motivation for survival. Instinct
is an example of fixed action patterns. Any behavior is instinctive if
it is performed in the absence of learning. Reflexes can be instincts.
For example, a newborn baby instinctively knows to search for and suckle
its mother's breast for nourishment.
Bowlby (and many other modern ethological theorists) believed that
humans spontaneously act to meet the demands of their environment. They
are active participants who seek out a parent, food, or a mate (i.e. an
infant will seek to remain within sight of a caretaker).
Vygotsky believed that the way humans think is based on the culture
they are raised in and the language they are surrounded by. He
emphasized that children grow up in the symbols of their culture,
especially linguistic symbols. These linguistic symbols categorize and
organize the world around them. This organization of the world is
internalized, which influence the way they think.
Human behavior tends to change based on the environment and the
surrounding challenges that individuals begin to face. Two evolutionary
advances in human behavior began as a way to allow humans to communicate
and collaborate. Infrastructure theorist, Mead and Wittgenstein,
theorized the creation of a collaboration in human foraging. This
collaboration created social goals amongst people and also created a
common ground. To coordinate their common goals, humans evolved a new
type of cooperative communication. This communication was based on
gestures that allowed humans to cooperate amongst themselves in order to
achieve their desired goals. This change in behavior is seen due to the evolving of their
environment. The environment demands survival and humans adapted their
behavior in order to survive. In other words, this is known as the shared intentionality
hypothesis. According to this hypothesis, human thinking evolved from a
self-focused, individual intentionality as an adaptation for "dealing
with problems of social coordination, specifically, problems presented
by individuals' attempts to collaborate and communicate with others."
This evolution happened in two steps, one leading from individual to
"joint intentionality" and the other from joint intentionality to
"collective intentionality".
Mechanistic theories view behavior as passive. This theory argues
that human behavior is in passivity through physiological drives and
emotional stimuli. Unlike mechanistic theories, organismic theories view
behavior as active. An organismic theory argues that an organism is
active in its behavior, meaning that it decides how it behaves and
initiates its own behaviors. Humans have intrinsic needs that they
desire to be met. These needs provide energy for humans to act upon
their needs in order to meet them, rather than being reactive to them.
The active theory on human behavior treats stimuli not as a cause of
behavior, but as opportunities humans can utilize to meet their demands.
Human ethology topics
As
applied to human behavior, in the majority of cases, topical behavior
results from motivational states and the intensity of a specific
external stimulus. Organisms with a high inner motivational state for
such a stimulus is called appetitive behavior. Other important concepts
of zooethology—e.g., territoriality, hierarchy, sensitive periods in ontogenesis—are also useful when discussing human behavior. Irenäus Eibl-Eibesfeldt's book Human Ethology is most important for how these concepts are applied to human behavior.
Human ethology has contributed in two particular ways to our understanding of the ontogeny
of behavior in humans. This has resulted, first, from the application
of techniques for the precise observation, description and
classification of naturally occurring behavior and, secondly, from the
ethological approach to the study of behavior, especially the
development of behavior in terms of evolution. Of particular interest
are questions relating to the function of a particular kind of behavior
(e.g., attachment behavior) and its adaptive value. The description of
the behavioral repertoire of a species, the recognition of patterns of
behavioral development and the classification of established behavioral
patterns are prerequisites for any comparison between different species
or between organisms of a single species. The ethological approach is
the study of the interaction between the organism with certain innate
species-specific structures and the environment for which the organism
is genetically programmed.
Invariant behavior patterns have a morphological basis, mainly in neuronal structures common to all members of a species and, depending on the kind of behavior, may also be common to a genus or family or a whole order, e.g., primates, or even to a whole class, e.g., mammals. In such structures we can retrace and follow the evolutionary process by which the environment produced structures, especially nervous systems and brains,
which generate adaptive behavior. In organisms with a high level of
organization, the processes in which the ethologist is especially
interested are those genetically preprogrammed motor and perceptual
processes that facilitate social interaction and communication, such as
facial expression and vocalization. If we consider the most highly developed means of communication, language and speech,
which is found in humans alone, the question arises as to the
biological foundation of this species-specific behavior and perceptual
skill. The ethologist examines this question primarily from the point of
view of ontogenetic development.
The main strength of human ethology has been its application of
established interpretive patterns to new problems. Based on theories,
concepts and methods that have proved successful in animal ethology, it
looks at human behavior from a new viewpoint. The essence of this is the
evolutionary perspective. But since ethologists have been relatively
unaffected by the long history of the humanities, they often refer to
facts and interpretations neglected by other social sciences. If we look
back at the history of the relationship between the life sciences and the social sciences,
we find two prevailing modes of theoretical orientation: on the one
hand, reductionism, i.e., attempts to reduce human action to
non-cognitive behavior; and on the other, attempts to separate human
action and human society from the animal world completely. The advent of
the theory of evolution in the 19th century brought no easy solution to
the problem of nature and nurture,
since it could still be "solved" in either a continuous or
discontinuous manner. Human ethology as much as any other discipline
significantly contributes to the obsolescence of such simple dichotomies.
Human Ethology has an increasing influence on the dialogue
between Human Sciences and Humanities as shown for example in the book Being Human - Bridging the Gap between the Sciences of Body and Mind.
Methodology
Ethologists
study behavior using two general methods: naturalistic observation and
laboratory experimentation. Ethologist's insistence on observing
organisms in their natural environment differentiates ethology from
related disciplines such as evolutionary psychology and sociobiology,
and their naturalistic observation "ranks as one of their main
contributions to psychology", Naturalistic Observation Ethologists believe that in order to study
species-specific behaviors, a species must be observed in its natural
environment. One can only understand the function of a behavior by
seeing how it specifically fits into the species natural environment
to fulfill a specific need. Ethologists follow a specific set of steps
when studying an organism:
Ethogram
A detailed description of the behavior of a species in its natural environment
Classification
Classify behaviors according to their function (how they encourage survival).
Compare
Compare how a behavior functions in different species and how different behaviors may serve the same function in other species.
Laboratory Experiments
Determine the immediate causes of the behavior described in the first three steps.
These steps fall in line with Tinbergen's "On Aims of Methods of Ethology" in which he states that every study of behavior must answer four questions to be considered legitimate:
function (adaptation)
evolution (phylogeny)
causation (mechanism)
development (ontogeny)
Diversity
Diversity is an important concept in ethology and evolutionary theory, both genetically and culturally.
Genetic diversity serves as a way for populations to adapt to
changing environments. With more variation, it is more likely that some
individuals in a population will possess variations of alleles that are
suited for the environment. Those individuals are more likely to survive
to produce offspring bearing that allele. The population will continue
for more generations because of the success of these individuals.
Population genetics includes several hypotheses and theories regarding
genetic diversity. The neutral theory of evolution proposes that
diversity is the result of the accumulation of neutral substitutions.
Diversifying selection is the hypothesis that two subpopulations of a
species live in different environments that select for different alleles
at a particular locus. This may occur, for instance, if a species has a
large range relative to the mobility of individuals within it.
Cultural diversity is also important. From a cultural
transmission standpoint, humans are the only animals to pass down
cumulative cultural knowledge to their offspring. While chimpanzees can
learn to use tools by watching other chimps around them, but humans are
able to pool their cognitive resources to create increasingly more
complex solutions to problems and more complex ways of interacting with
their environments. The diversity of cultures points to the idea that
humans are shaped by their environments, and also interact with
environments to shape them as well. Cultural diversity arises from
different human adaptations to different environmental factors, which in
turn shapes the environment, which in turn again shapes human behavior.
This cycle results in diverse cultural representations that ultimately
add to the survival of the human species. This approach is important as a
way to build a bridge between biological and social sciences, which
creates a better understanding of human ethology.
One example of human diversity is sexual orientation. Ethologists
have long noted that there are over 250 species of animals which
display homosexual
behaviors. Although no offspring are directly created from homosexual
behaviors, a closer look reveals how the genes for homosexuality can
persist. Homosexuality could decrease competition for heterosexual
mates. Homosexual family members could increase the resources available
to the children of their siblings without producing offspring to compete
for those resources (the gay uncle theory), thus creating better
chances for their siblings' offspring to survive. These related
offspring share the homosexual individual's genes—although to a lesser
extent than direct offspring would—including genes for homosexuality.
This causes a small but stable chance for future generations to be gay
as well, even if the gay family member produces no direct descendants.
Modularity of mind is the notion that a mind may, at least in part, be composed of innate neural structures or mental modules which have distinct, established, and evolutionarily developed functions. However, different definitions of "module" have been proposed by different authors. According to Jerry Fodor, the author of Modularity of Mind, a system can be considered 'modular' if its functions are made of multiple dimensions or units to some degree. One example of modularity in the mind is binding.
When one perceives an object, they take in not only the features of an
object, but the integrated features that can operate in sync or
independently that create a whole. Instead of just seeing red, round, plastic, and moving, the subject may experience a rolling red ball. Binding may suggest that the mind is modular because it takes multiple cognitive processes to perceive one thing.
Early investigations
Historically, questions regarding the functional architecture
of the mind have been divided into two different theories of the nature
of the faculties. The first can be characterized as a horizontal view
because it refers to mental processes as if they are interactions
between faculties such as memory, imagination, judgement, and
perception, which are not domain specific
(e.g., a judgement remains a judgement whether it refers to a
perceptual experience or to the conceptualization/comprehension
process). The second can be characterized as a vertical view because it
claims that the mental faculties are differentiated on the basis of
domain specificity, are genetically determined, are associated with
distinct neurological structures, and are computationally autonomous.
The vertical vision goes back to the 19th-century movement called phrenology and its founder Franz Joseph Gall.
Gall claimed that the individual mental faculties could be associated
precisely, in a one-to-one correspondence, with specific physical areas
of the brain. For example, someone's level of intelligence could be literally "read
off" from the size of a particular bump on his posterior parietal lobe.
Phrenology's practice was debunked scientifically by Pierre Flourens in
the 19th century. He destroyed parts of pigeons' and dogs' brains,
called lesions, and studied the organisms' resulting dysfunction. He was
able to conclude that while the brain localizes in some functions, it
also works as a unit and is not as localized as earlier phrenologists
thought. Before the early 20th century, Edward Bradford Titchener studied the
modules of the mind through introspection. He tried to determine the
original, raw perspective experiences of his subjects. For example, if
he wanted his subjects to perceive an apple, they would need to talk
about spatial characteristics of the apple and the different hues that
they saw without mentioning the apple.
Fodor's Modularity of Mind
In the 1980s, however, Jerry Fodor revived the idea of the modularity of mind, although without the notion of precise physical localizability. Drawing from Noam Chomsky's idea of the language acquisition device and other work in linguistics as well as from the philosophy of mind and the implications of optical illusions, he became a major proponent of the idea with the 1983 publication of Modularity of Mind.
According to Fodor, a module falls somewhere between the behaviorist and cognitivist views of lower-level processes.
Behaviorists
tried to replace the mind with reflexes, which are, according to Fodor,
encapsulated (cognitively impenetrable or unaffected by other cognitive
domains) and non-inferential (straight pathways with no information
added). Low-level processes are unlike reflexes in that they can be
inferential. This can be demonstrated by poverty of the stimulus
argument, which posits that children do not only learn language from
their environment, but are innately programmed with low-level processes
that help them seek and learn language. The proximate stimulus, that
which is initially received by the brain (such as the 2D image received
by the retina), cannot account for the resulting output (for example,
our 3D perception of the world), thus necessitating some form of
computation.
In contrast, cognitivists
saw lower-level processes as continuous with higher-level processes,
being inferential and cognitively penetrable (influenced by other
cognitive domains, such as beliefs). The latter has been shown to be
untrue in some cases, such as the Müller-Lyer illusion, which can persist despite a person's awareness of their existence. This is taken to indicate that other domains, including one's beliefs, cannot influence such processes.
Fodor arrives at the conclusion that such processes are
inferential like higher-order processes and encapsulated in the same
sense as reflexes.
Although he argued for the modularity of "lower level" cognitive processes in Modularity of Mind he also argued that higher-level cognitive processes are not modular since they have dissimilar properties. The Mind Doesn't Work That Way, a reaction to Steven Pinker's How the Mind Works, is devoted to this subject.
Fodor (1983) states that modular systems must—at least to "some interesting extent"—fulfill certain properties:
Domain specificity: modules only operate on certain kinds of inputs—they are specialised
Obligatory firing: modules process in a mandatory manner
Limited accessibility: what central processing can access from input system representations is limited
Fast speed: probably due to the fact that they are encapsulated
(thereby needing only to consult a restricted database) and mandatory
(time need not be wasted in determining whether or not to process
incoming input)
Informational encapsulation: modules need not refer to other psychological systems in order to operate
Shallow outputs: the output of modules is very simple
Specific breakdown patterns
Characteristic ontogeny: there is a regularity of development
Fixed neural architecture.
Pylyshyn
(1999) has argued that while these properties tend to occur with
modules, one—information encapsulation—stands out as being the real
signature of a module; that is the encapsulation of the processes inside
the module from both cognitive influence and from cognitive access. One example is that conscious awareness that the Müller-Lyer illusion is an illusion does not correct visual processing.
Evolutionary psychology and massive modularity
The definition of module
has caused confusion and dispute. In J.A. Fodor's views, modules can be
found in peripheral and low-level visual processing, but not in central
processing. Later, he narrowed the two essential features to domain-specificity and information encapsulation.
According to Frankenhuis and Ploeger, domain-specificity means that "a
given cognitive mechanism accepts, or is specialized to operate on, only
a specific class of information". Information encapsulation means that information processing in the
module cannot be affected by information in the rest of the brain. One
example is that the effects of an optical illusion, created by low-level
processes, persist despite high-level processing caused by conscious
awareness of the illusion itself.
Other perspectives on modularity come from evolutionary psychology. Evolutionary psychologists propose that the mind is made up of genetically influenced and domain-specific mental algorithms or computational modules, designed to solve specific evolutionary problems of the past. Modules are also used for central processing. This theory is sometimes referred to as massive modularity. Leda Cosmides and John Tooby
claimed that modules are units of mental processing that evolved in
response to selection pressures. To them, each module was a complex
computer that innately processed distinct parts of the world, like
facial recognition, recognizing human emotions, and problem-solving. On this view, much modern human psychological activity is rooted in adaptations that occurred earlier in human evolution, when natural selection was forming the modern human species.
A 2010 review by evolutionary psychologists Confer et al.
suggested that domain general theories, such as for "rationality", has
several problems: 1. Evolutionary theories using the idea of numerous
domain-specific adaptions have produced testable predictions that have
been empirically confirmed; the theory of domain-general rational
thought has produced no such predictions or confirmations. 2. The
rapidity of responses such as jealousy due to infidelity indicates a
domain-specific dedicated module rather than a general, deliberate,
rational calculation of consequences. 3. Reactions may occur
instinctively (consistent with innate knowledge) even if a person has
not learned such knowledge. One example being that in the ancestral
environment it is unlikely that males during development learn that
infidelity (usually secret) may cause paternal uncertainty (from
observing the phenotypes of children born many months later and making a
statistical conclusion from the phenotype dissimilarity to the
cuckolded fathers). With respect to general purpose problem solvers, Barkow, Cosmides, and Tooby (1992) have suggested in The Adapted Mind: Evolutionary Psychology and The Generation of Culture that a purely general problem solving mechanism is impossible to build due to the frame problem.
Clune et al. (2013) have argued that computer simulations of the
evolution of neural nets suggest that modularity evolves because,
compared to non-modular networks, connection costs are lower.
Several groups of critics, including psychologists working within evolutionary frameworks, argue that the massively modular theory of mind does little to explain
adaptive psychological traits. Proponents of other models of the mind
argue that the computational theory of mind
is no better at explaining human behavior than a theory with mind
entirely a product of the environment. Even within evolutionary
psychology there is discussion about the degree of modularity, either as
a few generalist modules or as many highly specific modules. Other critics suggest that there is little empirical support in favor of the domain-specific theory beyond performance on the Wason selection task, a task critics state is too limited in scope to test all relevant aspects of reasoning.Moreover, critics argue that Cosmides and Tooby's conclusions contain
several inferential errors and that the authors use untested
evolutionary assumptions to eliminate rival reasoning theories.
Criticisms of the notion of modular minds from genetics include
that it would take too much genetic information to form innate
modularity of mind, the limits to the possible amount of functional
genetic information being imposed by the number of mutations per
generation that led to the prediction that only a small part of the
human genome can be functional in an information-carrying way if an
impossibly high rate of lethal mutations is to be avoided, and that
selection against lethal mutations would have stopped and reversed any
increase in the amount of functional DNA long before it reached the
amount that would be required for modularity of mind. It is argued that
proponents of the theory of mind conflate this with the straw man
argument of assuming no function in any non-protein-coding DNA when
pointing at discoveries of some parts of non-coding DNA
having regulatory functions, while the actual argument of limited
amount of functional DNA does acknowledge that some parts of non-coding
DNA can have functions but putting bounds on the total amount of
information-bearing genetic material regardless of whether or not it
codes for proteins, in agreement with the discoveries of regulatory
functions of non-coding DNA extending only to parts of it and not be
generalized to all DNA that does not code for proteins. The maximum
amount of information-carrying heredity is argued to be too small to
form modular brains.
Wallace (2010) observes that the evolutionary psychologists' definition of "mind" has been heavily influenced by cognitivism and/or information processing definitions of the mind. Critics point out that these assumptions underlying evolutionary
psychologists' hypotheses are controversial and have been contested by
some psychologists, philosophers, and neuroscientists. For example, Jaak Panksepp,
an affective neuroscientist, point to the "remarkable degree of
neocortical plasticity within the human brain, especially during
development" and states that "the developmental interactions among
ancient special-purpose circuits and more recent general-purpose brain
mechanisms can generate many of the "modularized" human abilities that
evolutionary psychology has entertained."
Philosopher David Buller agrees with the general argument that
the human mind has evolved over time but disagrees with the specific
claims evolutionary psychologists make. He has argued that the
contention that the mind consists of thousands of modules, including
sexually dimorphic jealousy and parental investment modules, are
unsupported by the available empirical evidence. He has suggested that the "modules" result from the brain's developmental plasticity and that they are adaptive responses to local conditions, not past evolutionary environments. However, Buller has also stated that even if massive modularity is
false this does not necessarily have broad implications for evolutionary
psychology. Evolution may create innate motives even without innate
knowledge.
In contrast to modular mental structure, some theories posit domain-general processing,
in which mental activity is distributed across the brain and cannot be
decomposed, even abstractly, into independent units. A staunch defender
of this view is William Uttal, who argues in The New Phrenology
(2003) that there are serious philosophical, theoretical, and
methodological problems with the entire enterprise of trying to localise
cognitive processes in the brain. Part of this argument is that a successful taxonomy of mental processes has yet to be developed.
Merlin Donald argues that over evolutionary time the mind has gained adaptive advantage from being a general problem solver. The mind, as described by Donald, includes module-like "central"
mechanisms, in addition to more recently evolved "domain-general"
mechanisms.
Jürgen Habermas (1979): Communication and the Evolution of Society – the book that universal pragmatics appears in
Universal pragmatics (UP), also formal pragmatics, is the philosophical study of the necessary conditions for reaching an understanding through communication. The philosopherJürgen Habermas coined the term in his essay "What is Universal Pragmatics?" where he suggests that human competition, conflict, and strategic action are attempts to achieve understanding that have failed because of modal
confusions. The implication is that coming to terms with how people
understand or misunderstand one another could lead to a reduction of
social conflict.
By coming to an "understanding," he means at the very least when two or more social actors share the same meanings about certain words or phrases; and at the very most when these actors are confident that those meanings fit relevant social expectations (or a "mutually recognized normative background").
For Habermas, the goal of coming to an understanding is "intersubjective mutuality ... shared knowledge, mutual trust, and accord with one another". In other words, the underlying goal of coming to an understanding
would help to foster the enlightenment, consensus, and goodwill
necessary for establishing socially beneficial norms. Habermas' goal is
not primarily for subjective feeling alone but for the development of
shared (intersubjective) norms which in turn establish the social coordination needed for practical action in pursuit of shared and individual objectives (a form of action termed "communicative action").
Universal pragmatics (UP) is part of a larger project to rethink the relationship between philosophy and the individual sciences during a period of social crisis. The project is within the tradition of Critical Theory, a program that traces back to the work of Max Horkheimer.
UP shares with speech act theory, semiotics, and linguistics
an interest in the details of language use and communicative action.
However, unlike those fields, it insists on a difference between the
linguistic data that we observe in the 'analytic' mode, and the rational reconstruction of the rules of symbol systems
that each reader/listener possesses intuitively when interpreting
strings of words. In this sense, it is an examination of the two ways
that language usage can be analyzed: as an object of scientific
investigation, and as a 'rational reconstruction' of intuitive
linguistic 'know-how'.
Goals and methods
Universal pragmatics is associated with the philosophical method of rational reconstruction.
The basic concern in universal pragmatics is utterances (or speech acts)
in general. This is in contrast to most other fields of linguistics,
which tend to be more specialized, focusing exclusively on very specific
sorts of utterances such as sentences (which in turn are made up of words, morphemes, and phonemes).
For Habermas, the most significant difference between a sentence
and an utterance is in that sentences are judged according to how well
they make sense grammatically, while utterances are judged according to their communicative validity (see section 1). (1979:31)
Universal pragmatics is also distinct from the field of sociolinguistics, because universal pragmatics is only interested in the meanings of utterances if they have to do with claims about truth or rightness, while sociolinguistics is interested in all utterances in their social contexts. (1979:31, 33)
Three aspects of universal pragmatics
There are three ways to evaluate an utterance, according to UP. There are theories that deal with elementary propositions, theories of first-person sentences, and theories of speech acts.
A theory of elementary propositions investigates those things in the real world that are being referenced by an utterance, and the things that are implied by an utterance, or predicate it. For example, the utterance "The first Prime Minister of Canada" refers to a man who went by the name of Sir John A. Macdonald. And when a speaker delivers the utterance, "My husband is a lawyer", it implies that the speaker is married to a man.
A theory of first-person sentences examines the expression of the intentions of the actor(s) through language and in the first-person.
Finally, a theory of speech acts examines the setting of
standards for interpersonal relations through language. The basic goal
of speech act theory is to explain how and when utterances in general
are performative. (1979:34) Central to the notion of speech acts are the ideas of illocutionary force and perlocutionary force, both terms coined by philosopher J.L. Austin. Illocutionary force describes the intent of the speaker, while perlocutionary force means the effect an utterance has in the world, or more specifically, the effect on others.
A performative utterance is a sentence where an action being
performed is done by the utterance itself. For example: "I inform you
that you have a moustache", or "I promise you I will not burn down the
house". In these cases, the words are also taken as significant actions:
the act of informing and promising (respectively).
Habermas adds to this the observation that speech acts can either succeed or fail, depending on whether or not they succeed on influencing another person in the intended way. (1979:35)
This last method of evaluation—the theory of speech acts—is the domain that Habermas is most interested in developing as a theory of communicative action.
Communicative action
There
are a number of ways to approach Habermas's project of developing a
formal pragmatic analysis of communication. Because Habermas developed
it in order to have a normative and philosophical foundation for his
critical social theory, most of the inroads into formal pragmatics start
from sociology, specifically with what is called action theory.
Action theory concerns the nature of human action, especially the
manner in which collective actions are coordinated in a functioning
society.
The coordination and integration of social action have been explained in many ways by many theories. Rational choice theory and game theory
are two examples, which describe the integration of individuals into
social groups by detailing the complex manner in which individuals
motivated only by self-interest will form mutually beneficial and
cooperative social arrangements. In contrast to these, Habermas has
formulated a theory of communicative action. (Habermas 1984; 1987) This theory and the project of developing a formal pragmatic analysis of communication are inseparable.
Habermas makes a series of distinctions in the service of explaining social action. The first major differentiation he makes is between two social realms, the system and the lifeworld. These designate two distinct modes of social integration:
The kind of social integration accomplished in the system is accomplished through the functional integration of the consequences of actions.
It bypasses the consciousness of individuals and does not depend upon
their being oriented towards acting collectively. Economic and
industrial systems are great examples, often producing complex forms of
social integration and interdependence despite the openly competitive
orientations of individuals.
The social integration accomplished in the lifeworld, by contrast, depends upon the coordination of action plans and the conscious action-orientations of individuals.
It relies on processes of human interaction involving symbolic and
cultural forms of meaning. More specifically, as Habermas maintains, the
coordination of the lifeworld is accomplished through communicative
action.
Thus, communicative action is an indispensable facet of society.
It is at the heart of the lifeworld and is, Habermas claims,
responsible for accomplishing several fundamental social functions:
reaching understanding, cultural reproduction, coordinating action
plans, and socializing individuals.
However, Habermas is quick to note, different modes of
interaction can (in some ways) facilitate these social functions and
achieve integration within the lifeworld. This points towards the second
key distinction Habermas makes, which differentiates communicative action from strategic action.
The coordination of action plans, which constitutes the social
integration of the lifeworld, can be accomplished either through
consensus or influence.
Strategic action is action-oriented towards success, while
communicative action is action-oriented towards understanding. Both
involve the symbolic resources of the lifeworld and occur primarily by
way of linguistic interaction. On the one hand, actors employing
communicative actions draw on the uniquely impelling force of mutual
understanding to align the orientation of their action plans. It is this
subtle but insistent binding force of communicative interactions that
opens the door to an understanding of their meanings. On the other hand,
actors employing strategic actions do not exploit the potential of
communication that resides in the mutual recognition of a shared
action-oriented understanding. Instead, strategic actors relate to
others with no intention of reaching consensus or mutual understanding,
but only the intention of accomplishing pre-determined ends unrelated to
reaching an understanding. Strategic action often involves the use of
communicative actions to achieve the isolated intentions of individuals,
manipulating shared understanding in the service of private interests.
Thus, Habermas claims, strategic action is parasitic on communicative
action, which means communicative action is the primary mode of
linguistic interaction. Reaching a reciprocally defined understanding is
communication's basic function.
Keeping in mind this delineation of the object domain, the formal
pragmatics of communication can be more readily laid out. The essential
insight has already been mentioned, which is that communication is
responsible for irreplaceable modes of social integration, and this is
accomplished through the unique binding force of a shared understanding.
This is, in a sense, the pragmatic piece of formal pragmatics:
communication does something in the world. What needs to be explained
are the conditions for the possibility of what communication already
does. This is, in a sense, the formal piece of formal pragmatics: a
rational reconstruction of the deep generative structures that are the
universal conditions for the possibility of a binding and compelling
mutual understanding.
From here, Habermas heads the analysis in two directions. In one direction is a kind of linguistic analysis
(of speech acts), which can be placed under the heading of the validity
dimensions of communication. The other direction entails a
categorization of the idealized presuppositions of communication.
Communicative competence
Habermas
argues that when speakers are communicating successfully, they will
have to defend their meaning by using these four claims.
That they have uttered something understandably — or their statements are intelligible;
That they have given other people something to understand — or are speaking something true;
That the speaker is therefore understandable — or their intentions are recognized and appreciated for what they are; and,
That they have come to an understanding with another person — or, they have used words that both actors can agree upon. (1979:4)
Habermas is emphatic that these claims are universal—no human
communication oriented at achieving mutual understanding could possibly
fail to raise all of these validity claims. Additionally, to illustrate
that all other forms of communication are derived from that which is
oriented toward mutual understanding, he argues that there are no other
kinds of validity claims whatsoever. This is important because it is
the basis of Habermas' critique of postmodernism.
The fundamental orientation toward mutual understanding is at the heart of universal pragmatics, as Habermas explains:
"The task of universal pragmatics is to identify and
reconstruct universal conditions of possible mutual understanding...
other forms of social action—for example, conflict, competition,
strategic action in general—are derivatives of action-oriented toward
reaching understanding. Furthermore, since language is the specific
medium of reaching understanding at the sociocultural stage of
evolution, I want to go a step further and single out explicit speech
actions from other forms of communicative action."
Any meaning that meets the above criteria, and is recognized by another as meeting the criteria, is considered "vindicated" or communicatively competent.
In order for anyone to speak validly — and therefore, to have his
or her comments vindicated, and therefore reach a genuine consensus and
understanding — Habermas notes that a few more fundamental commitments
are required. First, he notes, actors have to treat this formulation of validity so seriously that it might be a precondition for any communication at all. Second, he asserts that all actors must believe that their claims are able to meet these standards of validity. And third, he insists that there must be a common conviction among actors that all validity claims are either already vindicated or could be vindicated.
Examining the validity of speech
Habermas
claims that communication rests upon a non-egoistic understanding of
the world, which is an idea he borrowed from thinkers like Jean Piaget.
A subject capable of a de-centered understanding can take up three
fundamentally different attitudes to the world. Habermas refers to such
attitudes as dimensions of validity. Specifically, this means individuals can recognize different standards for validity—i.e., that the validation of an empirical
truth claim requires different methods and procedures than the
validation of subjective truthfulness, and that both of those require
different methods and procedures of validation than claims to normative
rightness.
These dimensions of validity can be summarized as claims to truth (IT), truthfulness (I), and rightness (WE).
So the ability to differentiate between the attitudes (and their
respective "worlds") mentioned above should be understood as an ability
to distinguish between types of validity claims.
M. Cooke provided the only book-length treatment of Habermas's communication theory. Cooke explains:
"when we adopt an objectifying attitude we relate, in the first
instance to the objective world of facts and existing states of affairs
[IT]; when we adopt a norm-conformative attitude we relate, in the first
instance, to the social world of normatively regulated interactions
[WE]; when we adopt an expressive attitude we relate, in the first
instance to the subjective world of inner experience [I]". (Cooke 1994)
This is fundamental to Habermas's analysis of communication. He
maintains that the performance of any speech act necessarily makes
reference to these dimensions of validity, by raising at least three
validity claims.
One way to grasp this idea is to take an inventory of the ways in
which an attempt at communication can misfire, the ways a speech act
can fail. A hearer may reject the offering of a speech act on the
grounds that it is invalid because it:
presupposes or explicates states of affairs which are not the case (IT);
does not conform to accepted normative expectations (WE);
raises doubts about the intentions or sincerity of the speaker (I).
Of course, from this, it follows that a hearer who accepts the
offering of a speech act does so on the grounds that it is valid because
it:
presupposes or explicates states of affairs that are true (IT);
conforms to accepted normative expectations (WE);
raises no doubts concerning the intentions or sincerity of the speaker (I).
This means that when engaging in communication the speaker and hearer
are inescapably oriented to the validity of what is said. A speech act
can be understood as an offering, the success or failure of which
depends upon the hearer's response of either accepting or rejecting the
validity claims it raises. The three dimensions of validity pointed out
above are implicated in any attempt at communication.
Thus, communication relies on its being embedded within relations
to various dimensions of validity. Any and every speech act is infused
with inter-subjectively recognized claims to be valid. This implicitly
ties communication to argumentation and various discursive
procedures for the redemption of validity claims. This is true because
to raise a validity claim in communication is to simultaneously imply
that one is able to show, if challenged, that one's claim is justified.
Communication is possible because speakers are accountable for the
validity of what they say. This assumption of responsibility on the part
of the speaker is described by Habermas as a "warranty", because in most cases the validity claims raised during communication are taken as justified,
and communication proceeds on that basis. Similarly, hearers are
accountable for their stance taken up in relation to the validity claims
raised by the speaker. Both speaker and hearer are bound to the
validity claims raised by the utterances they share during
communication. They are bound by the weak obligations inherent in
pursuing actions oriented towards reaching an understanding. Habermas
would claim that this obligation is a rational one:
"With every speech act, by virtue of the validity claims it
raises, the speaker enters into an interpersonal relationship of mutual
obligation with the hearer: The speaker is obliged to support her claims
with reasons if challenged, and the hearer is obliged to accept a claim
unless he has good reason not to do so. The obligation in question is,
in the first instance, not a moral one but a rational one -- the penalty
of failure to fulfill it is the charge not of immorality but of
irrationality -- although clearly the two will often overlap" (Cooke,
1994).
This begins to point towards the idea of communicative rationality, which is the potential for rationality
that is implicit in the validity basis of everyday communication, the
shape of reason that can be extracted from Habermas's formal-pragmatic
analyses.
"The modern -- decentered -- understanding of the world has
opened up different dimensions of validity; to the extent that each
dimension of validity has its own standards of truth and falsity and its
own modes of justification for determining these, one may say that what
has been opened up are dimensions of rationality" (Cooke, 1994).
However, before the idea of communicative rationality can be
described, the other direction of Habermas's formal pragmatic analyses
of communication needs to be explained. This direction looks towards the
idealized presuppositions of communication.
Ideal presuppositions of communication
When
individuals pursue actions oriented towards reaching an understanding,
the speech acts they exchange take on the weight of a mutually
recognized validity. This means each actor involved in communication
takes the other as accountable
for what they have said, which implies that good reasons could be given
by all to justify the validity of the understanding that is being
achieved. Again, in most situations, the redemption of validity claims
is not an explicit undertaking (except in discourses, see below). Instead, each actor issues a "warranty"
of accountability to the other, which only needs to be redeemed if
certain validity claims are thrown into question. This suggests that the
validity claims raised in every communicative interaction implicitly
tie communication to argumentation.
It is here that the idealized presuppositions of communication
arise. Habermas claims that all forms of argumentation, even implicit
and rudimentary ones, rest upon certain "idealizing suppositions," which
are rooted in the very structures of action-oriented towards
understanding. These "strong idealizations" are always understood as at
least approximately satisfied by participants in situations where
argumentation (and communication) is thought to be taking place. Thus,
when during communication it is discovered that the belief that these
presuppositions are satisfied is not justified it is always taken as
problematic. As a result, steps are usually taken to reestablish and
maintain the belief that they are approximately satisfied, or
communication is simply called off.
The most basic of these idealized presuppositions is the presupposition that participants in communicative exchange are using the same linguistic expressions in the same way.
This is an obvious but interesting point, which clearly illustrates
what an idealized presupposition is. It is a presupposition because
communication would not proceed if those involved did not think it was
at least approximately satisfied (in this case that a shared language
was being used). It is idealized because no matter how closely it is
approximated it is always counterfactual (because, in this case, the fact is that all meanings are to some degree personally defined).
Another, basic idealized presupposition of argumentation is the presupposition that no relevant argument is suppressed or excluded by the participants.
Another is the presupposition that no persuasive force except that of the better argument is exerted.
There is also the presupposition that all the participants are motivated only by a concern for the better argument.
There is the presupposition of attributing a context-transcending significance to validity claims.
This presupposition is controversial but important (and becomes
expanded and clarified in the presuppositions of discourse, see below).
The idea is that participants in communication instill their claims with
a validity that is understood to have significance beyond the specific
context of their agreement.
The presupposition that no validity claim is exempt in principle from critical evaluation in argumentation;
The presupposition that everyone capable of speech and action is entitled to participate, and everyone is equally entitled to introduce new topics or express attitudes needs or desires.
In sum, all these presuppositions must be assumed to be approximately
satisfied in any situation of communication, despite their being
necessarily counterfactual. Habermas refers to the positing of these
idealized presuppositions as the "simultaneously unavoidable and trivial
accomplishments that sustain communicative action and argumentation".
Habermas calls discourses those forms of communication
that come sufficiently close to actually satisfying these
presuppositions. Discourses often occur within institutionalized
forms of argumentation that self-reflectively refine their procedures
of communication, and as a result, have a more rigorous set of
presuppositions in addition to the ones listed above.
A striking feature of discourse is that validity claims tend to
be explicitly thematized and there is the presupposition that all
possible interlocutors would agree to the universal validity of the conclusions reached. Habermas especially highlights this in what he calls theoretical discourses and practical discourses.
These are tied directly to two of the three dimensions of validity
discussed above: theoretical discourse being concerned with validity
claims thematized regarding objective states of affairs (IT); practical
discourse being concerned with validity claims thematized concerning the
rightness of norms governing social interactions (WE).
Habermas understands presupposition (5) to be responsible for
generating the self-understanding and continuation of theoretical and
practical discourses. Presupposition (5) points out that the validity of
an understanding reached in theoretical or practical discourse,
concerning some factual knowledge or normative principle, is always
expanded beyond the immediate context in which it is achieved. The idea
is that participants in discourses such as these presuppose that any
understanding reached could attain universal agreement
concerning its universal validity if these discourses could be relieved
of the constraints of time and space. This idealized presupposition
directs discourses concerning truth and normative certainty beyond the
contingencies of specific communicative situations and towards the
idealized achievements of universal consensus and universal validity. It
is a rational reconstruction of the conditions for the possibility of
earnest discourses concerning facts and norms. Recall that, for
Habermas, rational reconstructions aim at offering the most acceptable
account of what allows for the competencies already mastered by a wide
range of subjects. In order for discourse to proceed, the existence of facts and norms must be presupposed, yet the certainty of an absolute knowledge of them must be, in a sense, postponed.
Striking a Piagetian and Peircean chord, Habermas understands the deep structures of collective inquiry as developmental.
Thus, the presupposition shared by individuals involved in discourse is
taken to reflect this. The pursuit of truth and normative certainty is
taken to be motivated and grounded, not in some objective or social
world that is treated as a "given", but rather in a learning process.
Indeed, Habermas himself is always careful to formulate his work as a research project, open to refinement.
In any case, reconstructing the presuppositions and validity
dimensions inherent to communication is valuable because it brings into
relief the inescapable foundations of everyday practices. Communicative
action and the rudimentary forms of argumentation that orient the
greater part of human interaction cannot be left behind. By
reconstructing the deep structures of these Habermas has discovered a
seed of rationality planted in the very heart of the lifeworld. Everyday
practices, which are common enough to be trivial, such as reaching an
understanding with another, or contesting the reasons for pursuing a
course of action, contain an implicit and idealized rationality.
In other words, communication is always somewhat rational.
Communication could not occur if the participants thought that the
speech acts exchanged did not carry the weight of validity for which
those participating could be held accountable. Nor would anyone feel
that a conclusion was justified if it was achieved by any other means
than the uncoerced force of the better argument. Nor could the
specialized discourses of law, science and morality continue if the progress of knowledge and insight was denied in favor of relativism.
Criticism
It
is a question of how appropriate it is to speak of "communication"
without tense, and of "everyday practices" as though they cut across all
times and cultures. That they do cannot be assumed, and anthropology
provides evidence of significant difference. It is possible to ignore
these facts by limiting the scope of universal pragmatics to current
forms of discourse, but this runs the risk of contradicting Habermas's
own demand for (5). Moreover, the initial unease with the classical and liberal
views of rationality had to do precisely with their ahistorical
character and refusal, or perhaps inability, to acknowledge their own
origins in circumstances of the day. Their veneer of false universality
torn off by the likes of Foucault, it remains to be seen whether "universal" pragmatics can stand up to the same challenges posed by deconstruction and skepticism.
While there is general agreement that the Americas were first
settled from Asia, the pattern of migration and the place(s) of origin
in Eurasia of the peoples who migrated to the Americas remain unclear. The traditional theory is that Ancient Beringians moved when sea levels were significantly lowered due to the Quaternary glaciation,following herds of now-extinct Pleistocenemegafauna along ice-free corridors that stretched between the Laurentide and Cordilleran ice sheets. Another route proposed is that, either on foot or using boats, they migrated down the Pacific coast to South America as far as Chile. Any archaeological evidence of coastal occupation during the last Ice Age would now have been covered by the sea level rise, up to a hundred metres since then.
The precise date for the peopling of the Americas is a long-standing open question. While advances in archaeology, Pleistocenegeology, physical anthropology, and DNA analysis have progressively shed more light on the subject, significant questions remain unresolved. The Clovis First theory refers to the hypothesis that the Clovis culture represents the earliest human presence in the Americas about 13,000 years ago. Evidence of pre-Clovis cultures has accumulated and pushed back the possible date of the first peopling of the Americas.Academics generally believe that humans reached North America south of
the Laurentide Ice Sheet at some point between 15,000 and 20,000 years
ago. Some new controversial archaeological evidence suggests the possibility
that human arrival in the Americas may have occurred prior to the Last Glacial Maximum more than 20,000 years ago.
Map of the Americas showing pre-Clovis settlements
Historically, researchers believed a single theory explained the peopling of the Americas, focusing on findings from Blackwater Draw New Mexico, where human artifacts dated from the last ice age were found alongside the remains of extinct animals in 1930s. This led to the widespread belief in the "Clovis-first model," proposing that the first Americans migrated over the Beringia land bridge
from Asia during a time when glacial passages opened. This model linked
the first inhabitants to distinctive spear points, known as Clovis points, ranging in age from 13,250 to 12,800 years old.
Numerous claims of earlier human presence began to challenge the Clovis first model beginning in the 1990s, culminating in significant discoveries at Monte Verde, Chile, dating back 14,500 years. At Oregon's Paisley Caves, fossilized human feces date back 14,300 years. In Texas, at Buttermilk Creek complex, stone tool fragments date back 15,500 years. At Arroyo Seco 2 in Argentina, archaeologists discovered 14,000-year-old butchered animal bones. Meadowcroft Rockshelter in Pennsylvania may have a history of at least 16,000 years. As research progressed in the 2000s, the narrative shifted from a
single migration event to multiple small, diverse groups entering the
continent at various points in time. This indicates that people might have populated North and South America as early as 15,000 to 20,000 years ago, which some believe support a coastal migration route.
The genetic history of the Indigenous peoples of the Americas has highlighted populations that adapted over tens of thousands of years. Geneticists discovered that a Beringian population split from Siberian groups about 36,000 years ago. Around 25,000 years ago, they became isolated, forming a new genetic group linked to today's Indigenous populations, which divided into two main lineages between 14,500 and 17,000 years
ago reflecting the dispersal associated with the early peopling of the
Americas.
The Chiquihuite Cave in Mexico is a possible Upper Paleolithic archaeological site in the Astillero Mountains, Zacatecas State, in North-Central Mexico.
Chiquihuite Cave may be evidence of early human presence in the
Western Hemisphere up to 33,000 years ago. It is located 2,740 meters
(9000 feet) above sea level and about 1 kilometer higher than the valley
below. Stones discovered here, thought to be lithic artifacts, have been dated
to 26,000 years ago based on more than 50 samples of animal bone and
charcoal found in association with these stones. However, there is scholarly debate over whether the stones are truly
artifacts, human-made tools that are evidence of human presence, or if
they were formed naturally. No evidence of human DNA or hearths have been unearthed.
In addition, some argue that evidence points towards human
presence extending back 130,000 years near San Diego, California at the Cerutti Mastodon site, though this is outright rejected by the vast majority of scholars across multiple academic fields. Scholars such as David J. Meltzer
have emphasized the fact that there are no verified archaeological
sites in the Americas older than 16,000 years accepted by the academic
community at large, which questions claims of sites being 20,000, 25,000, or even 130,000 years old.
Environment during the latest glaciation
For an introduction to the radiocarbon dating techniques used by archaeologists and geologists, see radiocarbon dating.
Emergence and submergence of Beringia
Figure 1. Submergence of the Beringian land bridge with post-Last Glacial Maximum (LGM) rise in eustatic sea level.
During the Wisconsin glaciation, the Earth's ocean water was, to varying degrees over time, stored in glacier ice. As water accumulated in glaciers, the volume of water in the oceans correspondingly decreased, resulting in lowering of global sea level. The variation of sea level over time has been reconstructed using oxygen isotope
analysis of deep sea cores, the dating of marine terraces, and
high-resolution oxygen isotope sampling from ocean basins and modern ice
caps. A drop of eustatic sea level by about 60 to 120 metres (200 to 390 ft) from present-day levels, commencing around 30,000 years before present (BP), created Beringia, a durable and extensive geographic feature connecting Siberia with Alaska. With the rise of sea level after the Last Glacial Maximum
(LGM), the Beringian land bridge was again submerged. Estimates of the
final re-submergence of the Beringian land bridge based purely on
present bathymetry
of the Bering Strait and eustatic sea level curve place the event
around 11,000 years BP (Figure 1). Ongoing research reconstructing
Beringian paleogeography during deglaciation could change that estimate
and possible earlier submergence could further constrain models of human
migration into North America.
Glaciers
A map of the glaciated regions of North America during the Last Glacial Maximum
The onset of the Last Glacial Maximum after 30,000 years BP saw the
expansion of alpine glaciers and continental ice sheets that blocked
migration routes out of Beringia. By 21,000 years BP, and possibly
thousands of years earlier, the Cordilleran and Laurentide ice sheets coalesced east of the Rocky Mountains, closing off a potential migration route into the center of North America. Alpine glaciers in the coastal ranges and the Alaskan Peninsula isolated the interior of Beringia from the Pacific coast. Coastal alpine glaciers and lobes of Cordilleran ice coalesced into piedmont glaciers that covered large stretches of the coastline as far south as Vancouver Island and formed an ice lobe across the Straits of Juan de Fuca by 18,000 BP. Coastal alpine glaciers started to retreat around 19,000 BP while Cordilleran ice continued advancing in the Puget lowlands up to 16,800 BP. Even during the maximum extent of coastal ice, unglaciated refugia persisted on present-day islands, that supported terrestrial and marine mammals. As deglaciation occurred, refugia expanded until the coast became ice-free by 15,000 BP. The retreat of glaciers on the Alaskan Peninsula provided access from Beringia to the Pacific coast by around 17,000 BP. The ice barrier between interior Alaska and the Pacific coast broke up starting around 16,200 BP. The ice-free corridor to the interior of North America opened between 13,000 and 12,000 BP. Glaciation in eastern Siberia during the LGM was limited to alpine and
valley glaciers in mountain ranges and did not block access between
Siberia and Beringia.
Climate and biological environments
Vegetation cover at the Last Glacial Maximum period ~18,000 years ago, describing the type of vegetation cover present
The paleoclimates and vegetation of eastern Siberia and Alaska during
the Wisconsin glaciation have been deduced from high resolution oxygen
isotope data and pollenstratigraphy. Prior to the Last Glacial Maximum, climates in eastern Siberia
fluctuated between conditions approximating present day conditions and
colder periods. The pre-LGM warm cycles in Arctic Siberia saw flourishes
of megafaunas. The oxygen isotope record from the Greenland Ice Cap suggests that
these cycles after about 45,000 BP lasted anywhere from hundreds to
between one and two thousand years, with greater duration of cold
periods starting around 32,000 BP. The pollen record from Elikchan Lake, north of the Sea of Okhotsk,
shows a marked shift from tree and shrub pollen to herb pollen prior to
30,000 BP, as herb tundra replaced boreal forest and shrub steppe going
into the LGM. A similar record of tree/shrub pollen being replaced with herb pollen
as the LGM approached was recovered near the Kolyma River in Arctic
Siberia. The abandonment of the northern regions of Siberia due to rapid cooling
or the retreat of game species with the onset of the LGM has been
proposed to explain the lack of archaeological sites in that region
dating to the LGM. The pollen record from the Alaskan side shows shifts between herb/shrub
and shrub tundra prior to the LGM, suggesting less dramatic warming
episodes than those that allowed forest colonization on the Siberian
side. Diverse, though not necessarily plentiful, megafauna were present in those environments. Herb tundra dominated during the LGM, due to cold and dry conditions.
Coastal environments during the Last Glacial Maximum were complex. The lowered sea level, and an isostatic
bulge equilibrated with the depression beneath the Cordilleran Ice
Sheet, exposed the continental shelf to form a coastal plain. While much of the coastal plain was covered with piedmont glaciers, unglaciated refugia supporting terrestrial mammals have been identified on Haida Gwaii, Prince of Wales Island, and outer islands of the Alexander Archipelago. The now-submerged coastal plain has potential for more refugia. Pollen data indicate mostly herb/shrub tundra vegetation in unglaciated
areas, with some boreal forest towards the southern end of the range of
Cordilleran ice. The coastal marine environment remained productive, as indicated by fossils of pinnipeds. The highly productive kelp forests over rocky marine shallows may have been a lure for coastal migration. Reconstruction of the southern Beringian coastline also suggests potential for a highly productive coastal marine environment.
Pollen data indicate a warm period culminating between 17,000 and 13,000 BP followed by cooling between 13,000 and 11,500 BP. Coastal areas deglaciated rapidly as coastal alpine glaciers, then
lobes of Cordilleran ice, retreated. The retreat was accelerated as sea
levels rose and floated glacial termini. It has been estimated that the
coast range was fully ice-free between 16,000 and 15,000 BP. Littoral
marine organisms colonized shorelines as ocean water replaced glacial
meltwater. Replacement of herb/shrub tundra by coniferous forests was
underway by 15,000 BP north of Haida Gwaii. Eustatic sea level rise
caused flooding, which accelerated as the rate grew more rapid.
The inland Cordilleran and Laurentide ice sheets retreated more
slowly than did the coastal glaciers. Opening of an ice-free corridor
did not occur until after 13,000 to 12,000 BP. The early environment of the ice-free corridor was dominated by glacial
outwash and meltwater, with ice-dammed lakes and periodic flooding from
the release of ice-dammed meltwater. Biological productivity of the deglaciated landscape increased slowly. The earliest possible viability of the ice-free corridor as a human migration route has been estimated at 11,500 BP.
Birch forests were advancing across former herb tundra in
Beringia by 17,000 BP in response to climatic amelioration, indicating
increased productivity of the landscape.
Analyses of biomarkers and microfossils preserved in sediments
from Lake E5 and Burial Lake in northern Alaska suggest early humans
burned Beringian landscapes as early as 34,000 years ago. The authors of these studies suggest that fire was used as means of hunting megafauna.
Chronology, reasons for, and sources of migration
The Indigenous peoples of the Americas have an ascertained archaeological presence in the Americas dating back to about 15,000 years ago. More recent research, however, suggests a human presence dating to
between 18,000 and 26,000 years ago, during the Last Glacial Maximum. There remain uncertainties regarding the precise dating of individual sites and regarding conclusions drawn from population genetics studies of contemporary Native Americans.
Chronology
Map
of Beringia showing the exposed seafloor and glaciation at 40,000 years
ago and 16,000 years ago. The green arrow indicates the "interior
migration" model along an ice-free corridor separating the major
continental ice sheets, the red arrow indicates the "coastal migration" model, both leading to a "rapid colonization" of the Americas after c. 16,000 years ago.
In the early 21st century, the models of the chronology of migration are divided into two general approaches.
The first is the short chronology theory, that the first migration occurred after the LGM, which went into decline after about 19,000 years ago, and was then followed by successive waves of immigrants.
The second theory is the long chronology theory, which
proposes that the first group of people entered Beringia, including
ice-free parts of Alaska, at a much earlier date, possibly 40,000 years
ago, followed by a much later second wave of immigrants.
The Clovis First theory, which dominated thinking on New World anthropology for much of the 20th century, was challenged in the 2000s by the secure dating of archaeological sites in the Americas to before 13,000 years ago.
The archaeological sites in the Americas with the oldest dates
that have gained broad acceptance are all compatible with an age of
about 15,000 years. This includes the Buttermilk Creek Complex in Texas, the Meadowcroft Rockshelter site in Pennsylvania and the Monte Verde site in southern Chile. Archaeological evidence of pre-Clovis people points to the South Carolina Topper Site being 16,000 years old, at a time when the glacial maximum would have theoretically allowed for lower coastlines.
It has often been suggested that an ice-free corridor, in what is now Western Canada, would have allowed migration before the beginning of the Holocene.
However, a 2016 study has argued against this, suggesting that the
peopling of North America via such a corridor is unlikely to
significantly pre-date the earliest Clovis sites. The study concludes
that the ice-free corridor in what is now Alberta and British Columbia
"was gradually taken over by a boreal forest dominated by spruce and
pine trees" and that the "Clovis people likely came from the south, not
the north, perhaps following wild animals such as bison". An alternative hypothesis for the peopling of America is coastal migration,
which may have been feasible along the deglaciated (but now submerged)
coastline of the Pacific Northwest from about 16,000 years ago.
Figure 2. Schematic illustration of maternal (mtDNA) gene-flow in and out of Beringia (long chronology, single source model).
Pre-LGM migration across Beringia has been proposed to explain
purported pre-LGM ages of archaeological sites in the Americas such as Bluefish Caves and Old Crow Flats in the Yukon Territory, and Meadowcroft Rock Shelter in Pennsylvania. The oldest archaeological sites on the Alaskan side of Beringia date to around 14,000 BP.It is possible that a small founder population had entered Beringia
before that time. However, archaeological sites that date closer to the
LGM on either the Siberian or the Alaskan side of Beringia are lacking.
Biomarker and microfossil analyses of sediments from Lake E5 and Burial
Lake in northern Alaska suggest human presence in eastern Beringia as
early as 34,000 years ago. These sedimentary analyses have been suggested to be the only possibly
recoverable remnants of humans living in Alaska during the last Glacial
period.
At Old Crow Flats, mammoth bones have been found that are broken
in distinctive ways indicating human butchery. The radiocarbon dates on
these vary between 25,000 and 40,000 BP. Also, stone microflakes have
been found in the area indicating tool production. However, the interpretations of butcher marks and the geologic
association of bones at the Bluefish Cave and Old Crow Flats sites, and
the related Bonnet Plume site, have been called into question. No evidence of human remains have been discovered at these sites. In
addition to disputed archaeological sites, support for pre-LGM human
presence has been found in lake sediment records of northern Alaska.
Biomarker and microfossil analyses of sediments from Lake E5 and Burial
Lake in suggest human presence in eastern Beringia as early as 34,000
years ago. These analyses are indeed compelling in that they corroborate the
inferences made from the Bluefish Cave and Old Crow Flats sites.
In 2020, evidence emerged for a new pre-LGM site in North-Central Mexico. Chiquihuite cave, an archaeological site in Zacatecas State, has been dated to 26,000 years BP based on numerous lithic artefacts discovered there. However, there is scholarly debate over whether the artifacts should be
considered evidence of human activity or if they were formed naturally. No evidence of human DNA or hearth have been unearthed.
Pre-LGM human presence in South America rests partly on the chronology of the controversial Pedra Furada rock shelter in Piauí, Brazil. More recently, studies at the archaeological sites Santa Elina (27000–10000 years BP) in the midwest, and Rincão I (20000–12000 years BP) in southeastern Brazil also show associations of evidence of human
presence with sediments dating from before the LGM. A 2003 study dated
evidence for the controlled use of fire to before 40,000 years ago. Additional evidence has been adduced from the morphology of Luzia Woman fossil, which was described as Australo-Melanesian.
This interpretation was challenged in a 2003 review which concluded the
features in question could also have arisen by genetic drift. In November 2018, scientists of the University of São Paulo and Harvard University
released a study that contradicts the alleged Australo-Melanesian
origin of Luzia. Using DNA sequencing, the results showed that Luzia's
ancestry was entirely Native American.
Stones described as probable tools, hammerstones and anvils, have been found in southern California, at the Cerutti Mastodon site, that are associated with a mastodon
skeleton which appeared to have been processed by humans. The mastodon
skeleton was dated by thorium-230/uranium radiometric analysis, using
diffusion–adsorption–decay dating models, to around 130 thousand years
ago. No human bones were found and expert reaction was mixed; claims of
tools and bone processing were called "not plausible" by Prof. Tom Dillehay.
The Yana RiverRhino Horn site (RHS) has dated human occupation of eastern Arctic Siberia to 31,300 BP. That date has been interpreted by some as evidence that migration into
Beringia was imminent, lending credence to occupation of Beringia during
the LGM.However, the Yana RHS date is from the beginning of the cooling period that led into the LGM. A compilation of archaeological site dates throughout eastern Siberia
suggest that the cooling period caused a retreat of humans southwards. Pre-LGM lithic evidence in Siberia indicate a settled lifestyle that
was based on local resources, while post-LGM lithic evidence indicate a
more migratory lifestyle.
A 2021 discovery of human footprints in relict lake sediments near White Sands National Park in New Mexico demonstrated there was a verifiable human presence in the region dating back to the LGM between 18,000 and 26,000 years ago. Later studies, reported in October 2023, confirmed that the age of the human footprints to be "up to 23,000 years old". A 2025 study based on radiocarbon dating performed by two independent
labs provided an estimate for the White Sands footprints site of
>23,600-17,000 calibrated years Before Present.
The Clovis-first advocates have not accepted the veracity of
these findings. In 2022, they said, "The oldest evidence for
archaeological sites in the New World with large numbers of artifacts
occurring in discrete and minimally disturbed stratigraphic contexts
occur in eastern Beringia between 13,000 and 14,200 BP. South of the ice
sheets, the oldest such sites occur in association with the Clovis
complex. If humans managed to breach the continental ice sheets
significantly before 13,000 BP, there should be clear evidence for it in
the form of at least some stratigraphically discrete archaeological
components with a relatively high artifact count. So far, no such
evidence exists."
Map of Y-Chromosome Haplogroups – dominant haplogroups in pre-colonial populations with proposed migrations routes
Genetic studies have used high resolution analytical techniques
applied to DNA samples from modern Native Americans and Asian
populations regarded as their source populations to reconstruct the
development of human Y-chromosome DNA haplogroups (yDNA haplogroups) and human mitochondrial DNA haplogroups (mtDNA haplogroups) characteristic of Native American populations. Models of molecular evolution rates were used to estimate the ages at
which Native American DNA lineages branched off from their parent
lineages in Asia and to deduce the ages of demographic events. One model
(Tammetal 2007) based on Native American mtDNA Haplotypes (Figure 2)
proposes that migration into Beringia occurred between 30,000 and 25,000
BP, with migration into the Americas occurring around 10,000 to 15,000
years after isolation of the small founding population. Another model (Kitchen et al. 2008) proposes that migration into
Beringia occurred approximately 36,000 BP, followed by 20,000 years of
isolation in Beringia. A third model (Nomatto et al. 2009) proposes that migration into
Beringia occurred between 40,000 and 30,000 BP, with a pre-LGM migration
into the Americas followed by isolation of the northern population
following closure of the ice-free corridor. Evidence of Australo-Melanesians admixture in Amazonian populations was published in 2016.
A study of the diversification of mtDNA Haplogroups C and D from
southern Siberia and eastern Asia, respectively, suggests that the
parent lineage (Subhaplogroup D4h) of Subhaplogroup D4h3, a lineage
found among Native Americans and Han Chinese, emerged around 20,000 BP, constraining the emergence of D4h3 to post-LGM. Age estimates based on Y-chromosome micro-satellite diversity place origin of the American Haplogroup Q1a3a (Y-DNA) at around 15,000 to 10,000 BP. Greater consistency of DNA molecular evolution rate models with each
other and with archaeological data may be gained by the use of dated
fossil DNA to calibrate molecular evolution rates.
Although there is no archaeological evidence that can be used to direct support a coastal migration route during the Last Glacial Maximum, genetic analysis has been used to support this thesis. In addition to human genetic lineage, megafaunal DNA lineage can be used to trace movements of megafauna – large mammalian – as well as the early human groups who hunted them.
Bison,
a type of megafauna, have been identified as an ideal candidate for the
tracing of human migrations out of Europe because of both their
abundance in North America as well as being one of the first megafauna
for which ancient DNA was used to trace patterns of population movement.
Unlike other types of fauna that moved between the Americas and Eurasia
(mammoths, horses, and lions), Bison survived the North American extinction event that occurred at the end of the Pleistocene. Their genome,
however, contains evidence of a bottleneck – something that can be used
to test hypothesis on migrations between the two continents. Early human groups were largely nomadic,
relying on following food sources for survival. Mobility was part of
what made humans successful. As nomadic groups, early humans likely
followed the food from Eurasia to the Americas – part of the reason why
tracing megafaunal DNA is so helpful for garnering insight to these
migratory patterns.
The grey wolf originated in the Americas and migrated into Eurasia prior to the Last Glacial Maximum
– during which it was believed that remaining populations of the grey
wolf residing in North America faced extinction and were isolated from
the rest of the population. This, however, may not be the case. Radiocarbon dating of ancient grey wolf remains found in permafrost
deposits in Alaska show a continuous exchange of population from 12,500
radiocarbon years BP to beyond radiocarbon dating capabilities. This
indicates that there was viable passage for grey wolf populations to
exchange between the two continents.
These faunas' ability to exchange populations during the period
of the Last Glacial Maximum along with genetic evidence found from early
human remains in the Americas provides evidence to support pre-Clovis
migrations into the Americas.
Source populations
The Native American source population was formed in Siberia by the mixing of two distinct populations: Ancient North Eurasians and an ancient East Asian (ESEA) population. According to Jennifer Raff, the Ancient North Eurasian population mixed
with a daughter population of ancient East Asians, who they encountered
around 25,000 years ago, which led to the emergence of Native American
ancestral populations. However, the exact location where the admixture
took place is unknown, and the migratory movements that united the two
populations are a matter of debate.
One theory supposes that Ancient North Eurasians migrated south to East Asia, or Southern Siberia, where they would have encountered and mixed with ancient East Asians. Genetic evidence from Lake Baikal in Russia supports this area as the location where the admixture took place.
However, a third theory, the "Beringian standstill hypothesis",
suggests that East Asians instead migrated north to Northeastern
Siberia, where they mixed with ANE, and later diverged in Beringia,
where distinct Native American lineages formed. This theory is supported
by maternal and nuclear DNA evidence. According to Grebenyuk, after 20,000 BP, a branch of Ancient East
Asians migrated to Northeastern Siberia, and mixed with descendants of
the ANE, leading to the emergence of Ancient Paleo-Siberian and Native American populations in Extreme Northeastern Asia.
However, the Beringian standstill hypothesis is not supported by paternal
DNA evidence, which may reflect different population histories for
paternal and maternal lineages in Native Americans, which is not
uncommon and has been observed in other populations.
A 2019 study suggested that Native Americans are the closest living relatives to 10,000-year-old fossils found near the Kolyma River in northeastern Siberia.
A study published in July 2022 suggested that people in southern
China may have contributed to the Native American gene pool, based on
the discovery and DNA analysis of 14,000-year-old human fossils.
The contrast between the genetic profiles of the Hokkaido Jōmon
skeletons and the modern Ainu illustrates another uncertainty in source
models derived from modern DNA samples.
The development of high-resolution genomic analysis has provided
opportunities to further define Native American subclades and narrow the
range of Asian subclades that may be parent or sister subclades.
The common occurrence of the mtDNA Haplogroups A, B, C, and D
among eastern Asian and Native American populations has long been
recognized, along with the presence of haplogroup X. As a whole, the greatest frequency of the four Native American associated haplogroups occurs in the Altai-Baikal region of southern Siberia. Some subclades of C and D closer to the Native American subclades occur among Mongolian, Amur, Japanese, Korean, and Ainu populations.
With further definition of subclades related to Native American
populations, the requirements for sampling Asian populations to find the
most closely related subclades grow more specific. Subhaplogroups D1
and D4h3 have been regarded as Native American specific based on their
absence among a large sampling of populations regarded as potential
descendants of source populations, over a wide area of Asia. Among the 3,764 samples, the Sakhalin–lower Amur region was represented by 61 Oroks. In another study, Subhaplogroup D1a has been identified among the Ulchis of the lower Amur River region (4 among 87 sampled, or 4.6%), along with Subhaplogroup C1a (1 among 87, or 1.1%). Subhaplogroup C1a is regarded as a close sister clade of the Native American Subhaplogroup C1b.
Subhaplogroup D1a has also been found among ancient Jōmon skeletons from Hokkaido The modern Ainu are regarded as descendants of the Jōmon. The occurrence of the Subhaplogroups D1a and C1a in the lower Amur
region suggests a source population from that region distinct from the
Altai-Baikal source populations, where sampling did not reveal those two
particular subclades. The conclusions regarding Subhaplogroup D1 indicating potential source populations in the lower Amur and Hokkaido areas stand in contrast to the single-source migration model.
Subhaplogroup D4h3 has been identified among Han Chinese. Subhaplogroup D4h3 from China does not have the same geographic
implication as Subhaplotype D1a from Amur-Hokkaido, so its implications
for source models are more speculative. Its parent lineage, Subhaplotype
D4h, is believed to have emerged in East Asia, rather than Siberia,
around 20,000 BP. Subhaplogroup D4h2, a sister clade of D4h3, has also been found among Jōmon skeletons from Hokkaido. D4h3 has a coastal trace in the Americas.
X is one of the five mtDNA haplogroups found in Indigenous
Americans. Native Americans mostly belong to the X2a clade, which has
never been found in the Old World. According to Jennifer Raff,
X2a probably originated in the same Siberian population as the other
four founding maternal lineages, and that there is no compelling reason
to believe it is related to X lineages found in Europe or West Eurasia.
The Kennewick man
fossil was found to carry the deepest branch of the X2a haplogroup, and
he did not have any European ancestry that would be expected for a
European origin of the lineage.
HTLV-1 genomics
The Human T cell Lymphotrophic Virus 1 (HTLV-1)
is a virus transmitted through exchange of bodily fluids and from
mother to child through breast milk. The mother-to-child transmission
mimics a hereditary trait, although such transmission from maternal
carriers is less than 100%. The HTLV virus genome has been mapped, allowing identification of four
major strains and analysis of their antiquity through mutations. The
highest geographic concentrations of the strain HLTV-1 are in
sub-Saharan Africa and Japan. In Japan, it occurs in its highest concentration on Kyushu. It is also present among African descendants and native populations in the Caribbean region and South America. It is rare in Central America and North America. Its distribution in the Americas has been regarded as due to importation with the slave trade.
The Ainu have developed antibodies to HTLV-1, indicating its endemicity to the Ainu and its antiquity in Japan. A subtype "A" has been defined and identified among the Japanese (including Ainu), and among Caribbean and South American isolates. A subtype "B" has been identified in Japan and India. In 1995, Native Americans in coastal British Columbia were found to have both subtypes A and B. Bone marrow specimens from an Andean mummy about 1500 years old were reported to have shown the presence of the A subtype. The finding ignited controversy, with contention that the sample DNA
was insufficiently complete for the conclusion and that the result
reflected modern contamination. However, a re-analysis indicated that the DNA sequences were consistent
with, but not definitely from, the "cosmopolitan clade" (subtype A). The presence of subtypes A and B in the Americas is suggestive of a
Native American source population related to the Ainu ancestors, the Jōmon.
Physical anthropology
Paleo-Indian skeletons in the Americas such as Kennewick Man (Washington State), Hoya Negro skeleton (Yucatán), Luzia Woman and other skulls from the Lagoa Santa site (Brazil), Buhl Woman (Idaho), Peñon Woman III, two skulls from the Tlapacoya site (Mexico City), and 33 skulls from Baja California have exhibited certain craniofacial traits distinct from most modern
Native Americans, leading physical anthropologists to posit an earlier
"Paleoamerican" population wave. The most basic measured distinguishing trait is the dolichocephaly of the skull. Some modern isolated populations such as the Pericúes of Baja California and the Fuegians of Tierra del Fuego exhibit that same morphological trait.
Other anthropologists advocate an alternative hypothesis that evolution of an original Beringian phenotype
gave rise to a distinct morphology that was similar in all known
Paleoamerican skulls, followed by later convergence towards the modern
Native American phenotype.
Archaeogenetic studies do not support a two-wave model or the
Paleoamerican hypothesis of an Australo-Melanesian origin, and firmly
assign all Paleo-Indians and modern Native Americans to one ancient
population that entered the Americas in a single migration from
Beringia. Only in one ancient specimen (Lagoa Santa) and a few modern
populations in the Amazon region, a small Australasian ancestry
component of c. 3% was detected, which remains unexplained by the
current state of research (as of 2021), but may be explained by the presence of the more basal Tianyuan-related ancestry,
a deep East Asian lineage which did not directly contribute to modern
East Asians but may have contributed to the ancestors of Native
Americans in Siberia, as such ancestry is also found among previous
Paleolithic Siberians (Ancient North Eurasians).
A report published in the American Journal of Physical Anthropology
in January 2015 reviewed craniofacial variation focusing on differences
between early and late Native Americans and explanations for these
based on either skull morphology or molecular genetics. Arguments based
on molecular genetics have in the main, according to the authors,
accepted a single migration from Asia with a probable pause in Beringia,
plus later bi-directional gene flow. Some studies focusing on
craniofacial morphology have previously argued that Paleoamerican
remains have been described as closer to Australo-Melanesians and
Polynesians than to the modern series of Native Americans, suggesting
two entries into the Americas, an early one occurring before a
distinctive East Asian morphology developed (referred to in the paper as
the "Two Components Model"). Another "third model", the "Recurrent Gene
Flow" (RGF) model, attempts to reconcile the two, arguing that
circumarctic gene flow after the initial migration could account for
morphological changes. It specifically re-evaluates the original report
on the Hoya Negro skeleton which supported the RGF model, the authors
disagreed with the original conclusion which suggested that the skull
shape did not match those of modern Native Americans, arguing that the
"skull falls into a subregion of the morphospace occupied by both
Paleoamericans and some modern Native Americans."
Stemmed points
Stemmed
points are a lithic technology distinct from Beringian and Clovis
types. They have a distribution ranging from coastal East Asia to the
Pacific coast of South America. The emergence of stemmed points has been traced to Korea during the upper Paleolithic. The origin and distribution of stemmed points have been interpreted as a
cultural marker related to a source population from coastal East Asia.
Migration routes
Interior route
Clovis-First theory
Map
demonstrating the routes of the competing "Ice Free Corridor" and
"Coastal migration" hypotheses for human arrival into North America
Historically, theories about migration into the Americas have
revolved around migration from Beringia through the interior of North
America. The discovery of artifacts in association with Pleistocene
faunal remains near Clovis, New Mexico
in the early 1930s required extension of the timeframe for the
settlement of North America to the period during which glaciers were
still extensive. That led to the hypothesis of a migration route between
the Laurentide and Cordilleran ice sheets to explain the early
settlement. The Clovis site was host to a lithic technology
characterized by spear points with an indentation, or flute, where the
point was attached to the shaft. A lithic complex characterized by the Clovis Point
technology was subsequently identified over much of North America and
in South America. The association of Clovis complex technology with late
Pleistocene faunal remains led to the theory that it marked the arrival
of big game hunters that migrated out of Beringia and then dispersed
throughout the Americas, otherwise known as the Clovis First theory.
Recent radiocarbon dating of Clovis sites has yielded ages of
between 13,000 and 12,600 BP, somewhat later than dates derived from
older techniques. The re-evaluation of earlier radiocarbon dates led to the conclusion
that no fewer than 11 of the 22 Clovis sites with radiocarbon dates are
"problematic" and should be disregarded, including the type site
in Clovis, New Mexico. Numerical dating of Clovis sites has allowed
comparison of Clovis dates with dates of other archaeological sites
throughout the Americas, and of the opening of the ice-free corridor.
Both lead to significant challenges to the Clovis First theory. The
Monte Verde site of Southern Chile has been dated at 14,800 BP. The Paisley Cave site in eastern Oregon yielded a 14,500 BP, on a
coprolite with human DNA and radiocarbon dates of 13,200 and 12,900 BP
on horizons containing western stemmed points. Artifact horizons with non-Clovis lithic assemblages and pre-Clovis
ages occur in eastern North America, although the maximum ages tend to
be poorly constrained.
Recent studies have suggested that the ice-free corridor opened
later (around 13,800 ± 500 years ago) than the earliest widely accepted
archaeological sites in the Americas, suggesting that it could not have
been used as the route for the earliest peoples to migrate south.
An alternative to the Beringia route is proposed by the "stepping
stones" hypothesis. The frequent submergence of islands along the
Bering Transitory Archipelago would have forced the inhabitants of these
island to continue traveling across the archipelago until they reached
the mainland.
Lithic evidence of pre-Clovis migrations
1953 excavation of jasper projectile points from Deep Creek, Lake Mojave.
Geological findings on the timing of the ice-free corridor also
challenge the notion that Clovis and pre-Clovis human occupation of the
Americas was a result of migration through that route following the Last
Glacial Maximum. Pre-LGM closing of the corridor may approach 30,000 BP
and estimates of ice retreat from the corridor are in the range of
13,000 to 12,000 years ago. Viability of the corridor as a human migration route has been estimated
at 11,500 BP, later than the ages of the Clovis and pre-Clovis sites. Dated Clovis archaeological sites suggest a south-to-north spread of the Clovis culture.
Pre-LGM migration into the interior has been proposed to explain pre-Clovis ages for archaeological sites in the Americas, although pre-Clovis sites such as Meadowcroft Rock Shelter, Monte Verde, and Paisley Cave have not yielded confirmed pre-LGM ages.
There are many pre-Clovis sites in the American Southwest, particularly in the Mojave Desert. Lake Mojave quarries dating back to the Pleistocene
hold lithic remains of Silver Lake projectile points and Lake Mojave
projectile points. This indicates an interior movement into the region
as early as 13,800 BP, if not earlier.
A relationship between the Na-Dené languages of North America (such as Navajo and Apache), and the Yeniseian languages of Siberia was first proposed as early as 1923, and developed further by others. A detailed study was done by Edward Vajda and published in 2010. This theory received support from many linguists, with archaeological and genetic studies providing it with further support.
The Arctic Small Tool tradition
of Alaska and the Canadian Arctic may have originated in East Siberia
about 5,000 years ago. This is connected with the ancient Paleo-Eskimo peoples of the Arctic.
The Arctic Small Tool tradition source may have been the Syalakh-Bel'kachi-Ymyakhtakh culture sequence of East Siberia, dated to 6,500–2,800 BP.
The interior route is consistent with the spread of the Na-Dene language group and subhaplogroup X2a into the Americas after the earliest paleoamerican migration.
Nevertheless, some scholars suggest that the ancestors of western
North Americans speaking Na-Dene languages made a coastal migration by
boat.
Earlier interior route
It
is possible that humans arrived in the Americas by way of interior
routes that existed prior to the Last Glacial Maximum. Cosmogenic
exposure dating, a technique that analyzes when in Earth's history a
landscape was exposed to cosmic rays (and therefore unglaciated),
performed by Mark Swisher suggests that an older ice-free corridor
existed in North America 25,000 years ago. Swisher attributes sites such
as Monte Verde, Meadowcroft Rockshelter, Manis Mastodon site and Paisley Caves to this corridor.
The Pacific coastal migration theory proposes that people
first reached the Americas via water travel, following coastlines from
northeast Asia into the Americas, originally proposed in 1979 by Knute
Fladmark as an alternative to the hypothetical migration through an
ice-free inland corridor. This model would help to explain the rapid spread to coastal sites
extremely distant from the Bering Strait region, including sites such as
Monte Verde in southern Chile and Taima-Taima in western Venezuela.
The very similar marine migration hypothesis is a variant
of coastal migration; essentially its only difference is that it
postulates that boats were the principal means of travel. The proposed
use of boats adds a measure of flexibility to the chronology of coastal
migration, because a continuous ice-free coast (16–15,000 calibrated
years BP) would then not be required: Migrants in boats
could have easily bypassed ice barriers and settled in scattered coastal
refugia, before the deglaciation of the coastal land route was
complete. A maritime-competent source population in coastal East Asia is
an essential part of the marine migration hypothesis.
A 2007 article in the Journal of Island and Coastal Archaeology proposed a "kelp highway hypothesis", a variant of coastal migration based on the exploitation of kelp
forests along much of the Pacific Rim from Japan to Beringia, the
Pacific Northwest, and California, and as far as the Andean Coast of
South America. Once the coastlines of Alaska and British Columbia had
deglaciated about 16,000 years ago, these kelp forest (along with
estuarine, mangrove, and coral reef) habitats would have provided an
ecologically homogenous migration corridor, entirely at sea level, and
essentially unobstructed.
A 2016 DNA analysis of plants and animals suggest a coastal route was
feasible.
Mitochondrial subhaplogroup D4h3a, a rare subclade of D4h3 occurring along the west coast of the Americas, has been identified as a clade associated with coastal migration. This haplogroup was found in a skeleton referred to as Anzick-1, found in Montana in close association with several Clovis artifacts, dated 12,500 years ago.
Problems with evaluating coastal migration models
The
coastal migration models provide a different perspective on migration
to the New World, but they are not without their own problems: One such
problem is that global sea levels have risen over 120 metres (390 ft) since the end of the last glacial period, and this has submerged the
ancient coastlines that maritime people would have followed into the
Americas. Finding sites associated with early coastal migrations is
extremely difficult—and systematic excavation of any sites found in
deeper waters is challenging and expensive. Strategies for finding
earliest migration sites include identifying potential sites on
submerged paleoshorelines,
seeking sites in areas uplifted either by tectonics or isostatic
rebound, and looking for riverine sites in areas that may have attracted
coastal migrants. On the other hand, there is evidence of marine technologies found in the hills of the Channel Islands of California, circa 12,000 BP. If there was an early pre-Clovis coastal migration, there is always the possibility of a "failed colonization".
!["Maps depicting each phase of the three-step early human migrations for the peopling of the Americas. (A) Gradual population expansion of the Amerind ancestors from their Central East Asian gene pool (blue arrow). (B) Proto-Amerind occupation of Beringia with little to no population growth for ≈20,000 years. (C) Rapid colonization of the New World by a founder group migrating southward through the ice-free, inland corridor between the eastern Laurentide and western Cordilleran Ice Sheets (green arrow) and/or along the Pacific coast (red arrow). In (B), the exposed seafloor is shown at its greatest extent during the last glacial maximum at ≈20–18,000 years ago [25]. In (A) and (C), the exposed seafloor is depicted at ≈40,000 years ago and ≈16,0000 years ago, when prehistoric sea levels were comparable. A scaled-down version of Beringia today (60% reduction of A–C) is presented in the lower left corner. This smaller map highlights the Bering Strait that has geographically separated the New World from Asia since ≈11–10,000 years ago."](https://en.wikipedia.org/wiki/File:Journal.pone.0001596.g004.png)
_Fig_4.png)
