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Saturday, January 4, 2025

Theories about religion

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Theories_about_religion
 
Sociological, psychological, and anthropological theories about religion generally attempt to explain the origin and function of religion. These theories define what they present as universal characteristics of religious belief and practice.

History

From presocratic times, ancient authors advanced prescientific theories about religion. Herodotus (484–425 BCE) saw the gods of Greece as the same as the gods of Egypt. Euhemerus (about 330–264 BCE) regarded gods as excellent historical persons whom admirers eventually came to worship.

Scientific theories, inferred and tested by the comparative method, emerged after data from tribes and peoples all over the world became available in the 18th and 19th centuries. Max Müller (1823–1900) has the reputation of having founded the scientific study of religion; he advocated a comparative method that developed into comparative religion.

Subsequently, Clifford Geertz (1926–2006) and others questioned the validity of abstracting a general theory of all religions.

Classification

Theories of religion can be classified into:

  • Substantive (or essentialist) theories that focus on the contents of religions and the meaning the contents have for people. This approach asserts that people have faith because beliefs make sense insofar as they hold value and are comprehensible. The theories by Tylor and Frazer (focusing on the explanatory value of religion for its adherents), by Rudolf Otto (focusing on the importance of religious experience, more specifically experiences that are both fascinating and terrifying) and by Mircea Eliade (focusing on the longing for otherworldly perfection, the quest for meaning, and the search for patterns in mythology in various religions) offer examples of substantive theories.
  • Functional theories that focus on the social or psychological functions that religion has for a group or a person. In simple terms, the functional approach sees religion as "performing certain functions for society" Theories by Karl Marx (role of religion in capitalist and pre-capitalist societies), Sigmund Freud (psychological origin of religious beliefs), Émile Durkheim (social function of religions), and the theory by Stark and Bainbridge exemplify functional theories. This approach tends to be static, with the exception of Marx' theory, and unlike e.g. Weber's approach, which treats of the interaction and dynamic processes between religions and the rest of societies.
  • Social relational theories of religion that focus on the nature or social form of the beliefs and practices. Here, Charles Taylor's book The Secular Age is exemplary, as is the work of Clifford Geertz. The approach is expressed in Paul James's argument that religion is a "relatively bounded system of beliefs, symbols and practices that addresses the nature of existence through communion with others and Otherness, lived as both taking in and spiritually transcending socially grounded ontologies of time, space, embodiment and knowing". This avoids the dichotomy between the immanent and transcendental.

Other dichotomies according to which theories or descriptions of religions can be classified include:

Methodologies

Early essentialists, such as Tylor and Frazer, looked for similar beliefs and practices in all societies, especially the more primitive ones, more or less regardless of time and place. They relied heavily on reports made by missionaries, discoverers, and colonial civil servants. These were all investigators who had a religious background themselves, thus they looked at religion from the inside. Typically they did not practice investigative field work, but used the accidental reports of others. This method left them open to criticism for lack of universality, which many freely admitted. The theories could be updated, however, by considering new reports, which Robert Ranulph Marett (1866–1943) did for Tylor's theory of the evolution of religion.

Field workers deliberately sent out by universities and other institutions to collect specific cultural data made available a much greater database than random reports. For example, the anthropologist E. E. Evans-Pritchard (1902–1973) preferred detailed ethnographical study of tribal religion as more reliable. He criticised the work of his predecessors, Müller, Tylor, and Durkheim, as untestable speculation. He called them "armchair anthropologists".

A second methodology, functionalism, seeks explanations of religion that are outside of religion; i.e., the theorists are generally (but not necessarily) atheists or agnostics themselves. As did the essentialists, the functionalists proceeded from reports to investigative studies. Their fundamental assumptions, however, are quite different; notably, they apply methodological naturalism. When explaining religion they reject divine or supernatural explanations for the status or origins of religions because they are not scientifically testable. In fact, theorists such as Marett (an Anglican) excluded scientific results altogether, defining religion as the domain of the unpredictable and unexplainable; that is, comparative religion is the rational (and scientific) study of the irrational. The dichotomy between the two classifications is not bridgeable, even though they have the same methods, because each excludes the data of the other.

The functionalists and some of the later essentialists (among others E. E. Evans-Pritchard) have criticized the substantive view as neglecting social aspects of religion. Such critics go so far as to brand Tylor's and Frazer's views on the origin of religion as unverifiable speculation. The view of monotheism as more evolved than polytheism represents a mere preconception, they assert. There is evidence that monotheism is more prevalent in hunter societies than in agricultural societies. The view of a uniform progression in folkways is criticized as unverifiable, as the writer Andrew Lang (1844–1912) and E. E. Evans-Pritchard assert. The latter criticism presumes that the evolutionary views of the early cultural anthropologists envisaged a uniform cultural evolution. Another criticism supposes that Tylor and Frazer were individualists (unscientific). However, some support that supposed approach as worthwhile, among others the anthropologist Robin Horton. The dichotomy between the two fundamental presumptions - and the question of what data can be considered valid - continues.

Substantive theories

J. M. W. Turner's painting The Golden Bough, based on the Golden Bough incident in the Aeneid

Evolutionary theories

Evolutionary theories view religion as either an adaptation or a byproduct. Adaptationist theories view religion as being of adaptive value to the survival of Pleistocene humans. Byproduct theories view religion as a spandrel.

Edward Burnett Tylor

Edward Burnett Tylor

The anthropologist Edward Burnett Tylor (1832–1917) defined religion as belief in spiritual beings and stated that this belief originated as explanations of natural phenomena. Belief in spirits grew out of attempts to explain life and death. Primitive people used human dreams in which spirits seemed to appear as an indication that the human mind could exist independent of a body. They used this by extension to explain life and death, and belief in the after life. Myths and deities to explain natural phenomena originated by analogy and an extension of these explanations. His theory assumed that the psyches of all peoples of all times are more or less the same and that explanations in cultures and religions tend to grow more sophisticated via monotheist religions, such as Christianity and eventually to science. Tylor saw practices and beliefs in modern societies that were similar to those of primitive societies as survivals, but he did not explain why they survived.

James George Frazer

James George Frazer (1854–1941) followed Tylor's theories to a great extent in his book The Golden Bough, but he distinguished between magic and religion. Magic is used to influence the natural world in the primitive man's struggle for survival. He asserted that magic relied on an uncritical belief of primitive people in contact and imitation. For example, precipitation may be invoked by the primitive man by sprinkling water on the ground. He asserted that according to them magic worked through laws. In contrast religion is faith that the natural world is ruled by one or more deities with personal characteristics with whom can be pleaded, not by laws.

Rudolf Otto

The theologian Rudolf Otto (1869–1937) focused on religious experience, more specifically moments that he called numinous which means "Wholly Other". He described it as mysterium tremendum (terrifying mystery) and mysterium fascinans (awe inspiring, fascinating mystery). He saw religion as emerging from these experiences.

He asserted that these experiences arise from a special, non-rational faculty of the human mind, largely unrelated to other faculties, so religion cannot be reduced to culture or society. Some of his views, among others that the experience of the numinous was caused by a transcendental reality, are untestable and hence unscientific.

His ideas strongly influenced phenomenologists and Mircea Eliade.

Mircea Eliade

Mircea Eliade

Mircea Eliade's (1907–1986) approach grew out of the phenomenology of religion. Like Otto, he saw religion as something special and autonomous, that cannot be reduced to the social, economical or psychological alone. Like Durkheim, he saw the sacred as central to religion, but differing from Durkheim, he views the sacred as often dealing with the supernatural, not with the clan or society. The daily life of an ordinary person is connected to the sacred by the appearance of the sacred, called hierophany. Theophany (an appearance of a god) is a special case of it. In The Myth of the Eternal Return Eliade wrote that archaic men wish to participate in the sacred, and that they long to return to lost paradise outside the historic time to escape meaninglessness. The primitive man could not endure that his struggle to survive had no meaning. According to Eliade, man had a nostalgia (longing) for an otherworldly perfection. Archaic man wishes to escape the terror of time and saw time as cyclic. Historical religions like Christianity and Judaism revolted against this older concept of cyclic time. They provided meaning and contact with the sacred in history through the god of Israel.

Eliade sought and found patterns in myth in various cultures, e.g. sky gods such as Zeus.

Eliade's methodology was studying comparative religion of various cultures and societies more or less regardless of other aspects of these societies, often relying on second hand reports. He also used some personal knowledge of other societies and cultures for his theories, among others his knowledge of Hindu folk religion.

He has been criticized for vagueness in defining his key concepts. Like Frazer and Tylor he has also been accused of out-of-context comparisons of religious beliefs of very different societies and cultures. He has also been accused of having a pro-religious bias (Christian and Hindu), though this bias does not seem essential for his theory.

E. E. Evans-Pritchard

Bust of E. E. Evans-Pritchard in the Social and Cultural Anthropology Library, Oxford

The anthropologist Edward Evan Evans-Pritchard (1902–1973) did extensive ethnographic studies among the Azande and Nuer peoples who were considered "primitive" by society and earlier scholars. Evans-Pritchard saw these people as different, but not primitive.

Unlike the previous scholars, Evans-Pritchard did not propose a grand universal theory and he did extensive long-term fieldwork among "primitive" peoples, studying their culture and religion, among other among the Azande. Not just passing contact, like Eliade.

He argued that the religion of the Azande (witchcraft and oracles) can not be understood without the social context and its social function. Witchcraft and oracles played a great role in solving disputes among the Azande. In this respect he agreed with Durkheim, though he acknowledged that Frazer and Tylor were right that their religion also had an intellectual explanatory aspect. The Azande's faith in witchcraft and oracles was quite logical and consistent once some fundamental tenets were accepted. Loss of faith in the fundamental tenets could not be endured because of its social importance and hence they had an elaborate system of explanations (or excuses) against disproving evidence. Besides an alternative system of terms or school of thought did not exist.

He was heavily critical about earlier theorists of primitive religion with the exception of Lucien Lévy-Bruhl, asserting that they made statements about primitive people without having enough inside knowledge to make more than a guess. In spite of his praise of Bruhl's works, Evans-Pritchard disagreed with Bruhl's statement that a member of a "primitive" tribe saying "I am the moon" is prelogical, but that this statement makes perfect sense within their culture if understood metaphorically.

Apart from the Azande, Evans-Pritchard, also studied the neighbouring, but very different Nuer people. The Nuer had had an abstract monotheistic faith, somewhat similar to Christianity and Judaism, though it included lesser spirits. They had also totemism, but this was a minor aspect of their religion and hence a corrective to Durkheim's generalizations should be made. Evans-Pritchard did not propose a theory of religions, but only a theory of the Nuer religion.

Clifford Geertz

The anthropologist Clifford Geertz (1926–2006) made several studies in Javanese villages. He avoided the subjective and vague concept of group attitude as used by Ruth Benedict by using the analysis of society as proposed by Talcott Parsons who in turn had adapted it from Max Weber. Parsons' adaptation distinguished all human groups on three levels i.e. 1. an individual level that is controlled by 2. a social system that is in turn controlled by 3. a cultural system. Geertz followed Weber when he wrote that "man is an animal suspended in webs of significance he himself has spun and the analysis of it to be therefore not an experimental science in search of law but an interpretive one in search of meaning". Geertz held the view that mere explanations to describe religions and cultures are not sufficient: interpretations are needed too. He advocated what he called thick descriptions to interpret symbols by observing them in use, and for this work, he was known as a founder of symbolic anthropology.

Geertz saw religion as one of the cultural systems of a society. He defined religion as:

(1) a system of symbols
(2) which acts to establish powerful, pervasive and long-lasting moods and motivations in men
(3) by formulating conceptions of a general order of existence and
(4) clothing these conceptions with such an aura of factuality that
(5) the moods and motivations seem uniquely realistic.

With symbols Geertz meant a carrier that embodies a conception, because he saw religion and culture as systems of communication.

This definition emphasizes the mutual reinforcement between world view and ethos.

Though he used more or less the same methodology as Evans-Pritchard, he did not share Evans-Pritchard's hope that a theory of religion could ever be found. Geertz proposed methodology was not the scientific method of the natural science, but the method of historians studying history.

Functional theories

Karl Marx

Karl Marx (1818–1883)

The social philosopher Karl Marx (1818–1883) held a materialist worldview. According to Marx, the dynamics of society were determined by the relations of production, that is, the relations that its members needed to enter into to produce their means of survival.

Developing on the ideas of Ludwig Feuerbach, he saw religion as a product of alienation that was functional to relieving people's immediate suffering, and as an ideology that masked the real nature of social relations. He deemed it a contingent part of human culture, that would have disappeared after the abolition of class society.

These claims were limited, however, to his analysis of the historical relationship between European cultures, political institutions, and their Christian religious traditions.

Marxist views strongly influenced individuals' comprehension and conclusions about society, among others the anthropological school of cultural materialism.

Marx' explanations for all religions, always, in all forms, and everywhere have never been taken seriously by many experts in the field, though a substantial fraction accept that Marx' views possibly explain some aspects of religions.

Some recent work has suggested that, while the standard account of Marx's analysis of religion is true, it is also only one side of a dialectical account, which takes seriously the disruptive, as well as the pacifying moments of religion

Sigmund Freud

Sigmund Freud, 1885

Sigmund Freud (1856–1939) saw religion as an illusion, a belief that people very much wanted to be true. Unlike Tylor and Frazer, Freud attempted to explain why religion persists in spite of the lack of evidence for its tenets. Freud asserted that religion is a largely unconscious neurotic response to repression. By repression Freud meant that civilized society demands that we not fulfill all our desires immediately, but that they have to be repressed. Rational arguments to a person holding a religious conviction will not change the neurotic response of a person. This is in contrast to Tylor and Frazer, who saw religion as a rational and conscious, though primitive and mistaken, attempt to explain the natural world.

In his 1913 book Totem and Taboo he developed a speculative story about how all monotheist religions originated and developed. In the book he asserted that monotheistic religions grew out of a homicide in a clan of a father by his sons. This incident was subconsciously remembered in human societies.

In Moses and Monotheism, Freud proposed that Moses had been a priest of Akhenaten who fled Egypt after the pharaoh's death and perpetuated monotheism through a different religion.

Freud's view on religion was embedded in his larger theory of psychoanalysis, which has been criticized as unscientific. Although Freud's attempt to explain the historical origins of religions have not been accepted, his generalized view that all religions originate from unfulfilled psychological needs is still seen as offering a credible explanation in some cases.

Émile Durkheim

Émile Durkheim (1858–1917)

Émile Durkheim (1858–1917) saw the concept of the sacred as the defining characteristic of religion, not faith in the supernatural. He saw religion as a reflection of the concern for society. He based his view on recent research regarding totemism among the Australian aboriginals. With totemism he meant that each of the many clans had a different object, plant, or animal that they held sacred and that symbolizes the clan. Durkheim saw totemism as the original and simplest form of religion. According to Durkheim, the analysis of this simple form of religion could provide the building blocks for more complex religions. He asserted that moralism cannot be separated from religion. The sacred i.e. religion reinforces group interest that clash very often with individual interests. Durkheim held the view that the function of religion is group cohesion often performed by collectively attended rituals. He asserted that these group meeting provided a special kind of energy, which he called effervescence, that made group members lose their individuality and to feel united with the gods and thus with the group. Differing from Tylor and Frazer, he saw magic not as religious, but as an individual instrument to achieve something.

Durkheim's proposed method for progress and refinement is first to carefully study religion in its simplest form in one contemporary society and then the same in another society and compare the religions then and only between societies that are the same. The empirical basis for Durkheim's view has been severely criticized when more detailed studies of the Australian aboriginals surfaced. More specifically, the definition of religion as dealing with the sacred only, regardless of the supernatural, is not supported by studies of these aboriginals. The view that religion has a social aspect, at the very least, introduced in a generalized very strong form by Durkheim has become influential and uncontested.

Durkheim's approach gave rise to functionalist school in sociology and anthropology. Functionalism is a sociological paradigm that originally attempted to explain social institutions as collective means to fill individual biological needs, focusing on the ways in which social institutions fill social needs, especially social stability. Thus because Durkheim viewed society as an "organismic analogy of the body, wherein all the parts work together to maintain the equilibrium of the whole, religion was understood to be the glue that held society together.".

Bronisław Malinowski

The anthropologist Bronisław Malinowski (1884–1942) was strongly influenced by the functionalist school and argued that religion originated from coping with death. He saw science as practical knowledge that every society needs abundantly to survive and magic as related to this practical knowledge, but generally dealing with phenomena that humans cannot control.

Max Weber

Max Weber

Max Weber (1864–1920) thought that the truth claims of religious movement were irrelevant for the scientific study of the movements. He portrayed each religion as rational and consistent in their respective societies. Weber acknowledged that religion had a strong social component, but diverged from Durkheim by arguing, for example in his book The Protestant Ethic and the Spirit of Capitalism that religion can be a force of change in society. In the book Weber wrote that modern capitalism spread quickly partially due to the Protestant worldly ascetic morale. Weber's main focus was not on developing a theory of religion but on the interaction between society and religion, while introducing concepts that are still widely used in the sociology of religion. These concept include

  • Church sect typology, Weber distinguished between sects and churches by stating that membership of a sect is a personal choice and church membership is determined by birth. The typology later developed more extensively by his friend Ernst Troeltsch and others. According to the typology, churches, ecclesia, denomination, and sects form a continuum with decreasing influence on society. Sects are protest break away groups and tend to be in tension with society.
  • Ideal type, a hypothetical "pure" or "clear" form, used in typologies
  • Charismatic authority Weber saw charisma as a volatile form or authority that depends on the acceptance of unique quality of a person by this person's followers. Charisma can be a revolutionary force and the authority can either be routinized (change into other forms of authority) or disappear upon the death of the charismatic person.

Somewhat differing from Marx, Weber dealt with status groups, not with class. In status groups the primary motivation is prestige and social cohesion. Status groups have differing levels of access to power and prestige and indirectly to economic resources. In his 1920 treatment of the religion in China he saw Confucianism as helping a certain status group, i.e. the educated elite to maintain access to prestige and power. He asserted that Confucianism opposition against both extravagance and thrift made it unlikely that capitalism could have originated in China.

He used the concept of Verstehen (German for "understanding") to describe his method of interpretation of the intention and context of human action.

Rational choice theory

The rational choice theory has been applied to religions, among others by the sociologists Rodney Stark (1934–2022) and William Sims Bainbridge (born 1940). They see religions as systems of "compensators", and view human beings as "rational actors, making choices that she or he thinks best, calculating costs and benefits". Compensators are a body of language and practices that compensate for some physical lack or frustrated goal. They can be divided into specific compensators (compensators for the failure to achieve specific goals), and general compensators (compensators for failure to achieve any goal). They define religion as a system of compensation that relies on the supernatural. The main reasoning behind this theory is that the compensation is what controls the choice, or in other words the choices which the "rational actors" make are "rational in the sense that they are centered on the satisfaction of wants".

It has been observed that social or political movements that fail to achieve their goals will often transform into religions. As it becomes clear that the goals of the movement will not be achieved by natural means (at least within their lifetimes), members of the movement will look to the supernatural to achieve what cannot be achieved naturally. The new religious beliefs are compensators for the failure to achieve the original goals. Examples of this include the counterculture movement in America: the early counterculture movement was intent on changing society and removing its injustice and boredom; but as members of the movement proved unable to achieve these goals they turned to Eastern and new religions as compensators.

Most religions start out their lives as cults or sects, i.e. groups in high tension with the surrounding society, containing different views and beliefs contrary to the societal norm. Over time, they tend to either die out, or become more established, mainstream and in less tension with society. Cults are new groups with a new novel theology, while sects are attempts to return mainstream religions to (what the sect views as) their original purity. Mainstream established groups are called denominations. The comments below about cult formation apply equally well to sect formation.

There are four models of cult formation: the Psychopathological Model, the Entrepreneurial Model, the Social Model and the Normal Revelations model.

  • Psychopathological model: religions are founded during a period of severe stress in the life of the founder. The founder suffers from psychological problems, which they resolve through the founding of the religion. (The development of the religion is for them a form of self-therapy, or self-medication.)
  • Entrepreneurial model: founders of religions act like entrepreneurs, developing new products (religions) to sell to consumers (to convert people to). According to this model, most founders of new religions already have experience in several religious groups before they begin their own. They take ideas from the pre-existing religions, and try to improve on them to make them more popular.
  • Social model: religions are founded by means of social implosions. Members of the religious group spend less and less time with people outside the group, and more and more time with each other within it. The level of affection and emotional bonding between members of a group increases, and their emotional bonds to members outside the group diminish. According to the social model, when a social implosion occurs, the group will naturally develop a new theology and rituals to accompany it.
  • Normal revelations: religions are founded when the founder interprets ordinary natural phenomena as supernatural; for instance, ascribing his or her own creativity in inventing the religion to that of the deity.

Some religions are better described by one model than another, though all apply to differing degrees to all religions.

Once a cult or sect has been founded, the next problem for the founder is to convert new members to it. Prime candidates for religious conversion are those with an openness to religion, but who do not belong or fit well in any existing religious group. Those with no religion or no interest in religion are difficult to convert, especially since the cult and sect beliefs are so extreme by the standards of the surrounding society. But those already happy members of a religious group are difficult to convert as well, since they have strong social links to their preexisting religion and are unlikely to want to sever them in order to join a new one. The best candidates for religious conversion are those who are members of or have been associated with religious groups (thereby showing an interest or openness to religion), yet exist on the fringe of these groups, without strong social ties to prevent them from joining a new group.

Potential converts vary in their level of social connection. New religions best spread through pre-existing friendship networks. Converts who are marginal with few friends are easy to convert, but having few friends to convert they cannot add much to the further growth of the organization. Converts with a large social network are harder to convert, since they tend to have more invested in mainstream society; but once converted they yield many new followers through their friendship network.

Cults initially can have quite high growth rates; but as the social networks that initially feed them are exhausted, their growth rate falls quickly. On the other hand, the rate of growth is exponential (ignoring the limited supply of potential converts): the more converts you have, the more missionaries you can have out looking for new converts. But nonetheless it can take a very long time for religions to grow to a large size by natural growth. This often leads to cult leaders giving up after several decades, and withdrawing the cult from the world.

It is difficult for cults and sects to maintain their initial enthusiasm for more than about a generation. As children are born into the cult or sect, members begin to demand a more stable life. When this happens, cults tend to lose or de-emphasise many of their more radical beliefs, and become more open to the surrounding society; they then become denominations.

The theory of religious economy sees different religious organizations competing for followers in a religious economy, much like the way businesses compete for consumers in a commercial economy. Theorists assert that a true religious economy is the result of religious pluralism, giving the population a wider variety of choices in religion. According to the theory, the more religions there are, the more likely the population is to be religious and hereby contradicting the secularization thesis.

Ecological engineering

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Ecological_engineering
 
River restoration to restore ecosystem services is one common application of ecological engineering

Ecological engineering uses ecology and engineering to predict, design, construct or restore, and manage ecosystems that integrate "human society with its natural environment for the benefit of both".

Origins, key concepts, definitions, and applications

Ecological engineering emerged as a new idea in the early 1960s, but its definition has taken several decades to refine. Its implementation is still undergoing adjustment, and its broader recognition as a new paradigm is relatively recent. Ecological engineering was introduced by Howard Odum and others as utilizing natural energy sources as the predominant input to manipulate and control environmental systems. The origins of ecological engineering are in Odum's work with ecological modeling and ecosystem simulation to capture holistic macro-patterns of energy and material flows affecting the efficient use of resources.

Mitsch and Jorgensen summarized five basic concepts that differentiate ecological engineering from other approaches to addressing problems to benefit society and nature: 1) it is based on the self-designing capacity of ecosystems; 2) it can be the field (or acid) test of ecological theories; 3) it relies on system approaches; 4) it conserves non-renewable energy sources; and 5) it supports ecosystem and biological conservation.

Mitsch and Jorgensen were the first to define ecological engineering as designing societal services such that they benefit society and nature, and later noted the design should be systems based, sustainable, and integrate society with its natural environment.

Bergen et al. defined ecological engineering as: 1) utilizing ecological science and theory; 2) applying to all types of ecosystems; 3) adapting engineering design methods; and 4) acknowledging a guiding value system.

Barrett (1999) offers a more literal definition of the term: "the design, construction, operation and management (that is, engineering) of landscape/aquatic structures and associated plant and animal communities (that is, ecosystems) to benefit humanity and, often, nature." Barrett continues: "other terms with equivalent or similar meanings include ecotechnology and two terms most often used in the erosion control field: soil bioengineering and biotechnical engineering. However, ecological engineering should not be confused with 'biotechnology' when describing genetic engineering at the cellular level, or 'bioengineering' meaning construction of artificial body parts."

The applications in ecological engineering can be classified into 3 spatial scales: 1) mesocosms (~0.1 to hundreds of meters); 2) ecosystems (~one to tens of km); and 3) regional systems (>tens of km). The complexity of the design likely increases with the spatial scale. Applications are increasing in breadth and depth, and likely impacting the field's definition, as more opportunities to design and use ecosystems as interfaces between society and nature are explored. Implementation of ecological engineering has focused on the creation or restoration of ecosystems, from degraded wetlands to multi-celled tubs and greenhouses that integrate microbial, fish, and plant services to process human wastewater into products such as fertilizers, flowers, and drinking water. Applications of ecological engineering in cities have emerged from collaboration with other fields such as landscape architecture, urban planning, and urban horticulture, to address human health and biodiversity, as targeted by the UN Sustainable Development Goals, with holistic projects such as stormwater management. Applications of ecological engineering in rural landscapes have included wetland treatment and community reforestation through traditional ecological knowledge. Permaculture is an example of broader applications that have emerged as distinct disciplines from ecological engineering, where David Holmgren cites the influence of Howard Odum in development of permaculture.

Design guidelines, functional classes, and design principles

Ecological engineering design will combine systems ecology with the process of engineering design. Engineering design typically involves problem formulation (goal), problem analysis (constraints), alternative solutions search, decision among alternatives, and specification of a complete solution. A temporal design framework is provided by Matlock et al., stating the design solutions are considered in ecological time. In selecting between alternatives, the design should incorporate ecological economics in design evaluation and acknowledge a guiding value system which promotes biological conservation, benefiting society and nature.

Ecological engineering utilizes systems ecology with engineering design to obtain a holistic view of the interactions within and between society and nature. Ecosystem simulation with Energy Systems Language (also known as energy circuit language or energese) by Howard Odum is one illustration of this systems ecology approach. This holistic model development and simulation defines the system of interest, identifies the system's boundary, and diagrams how energy and material moves into, within, and out of, a system in order to identify how to use renewable resources through ecosystem processes and increase sustainability. The system it describes is a collection (i.e., group) of components (i.e., parts), connected by some type of interaction or interrelationship, that collectively responds to some stimulus or demand and fulfills some specific purpose or function. By understanding systems ecology the ecological engineer can more efficiently design with ecosystem components and processes within the design, utilize renewable energy and resources, and increase sustainability.

Mitsch and Jorgensen identified five Functional Classes for ecological engineering designs:

  1. Ecosystem utilized to reduce/solve pollution problem. Example: phytoremediation, wastewater wetland, and bioretention of stormwater to filter excess nutrients and metals pollution
  2. Ecosystem imitated or copied to address resource problem. Example: forest restoration, replacement wetlands, and installing street side rain gardens to extend canopy cover to optimize residential and urban cooling
  3. Ecosystem recovered after disturbance. Example: mine land restoration, lake restoration, and channel aquatic restoration with mature riparian corridors
  4. Ecosystem modified in ecologically sound way. Example: selective timber harvest, biomanipulation, and introduction of predator fish to reduce planktivorous fish, increase zooplankton, consume algae or phytoplankton, and clarify the water.
  5. Ecosystems used for benefit without destroying balance. Example: sustainable agro-ecosystems, multispecies aquaculture, and introducing agroforestry plots into residential property to generate primary production at multiple vertical levels.

Mitsch and Jorgensen identified 19 Design Principles for ecological engineering, yet not all are expected to contribute to any single design:

  1. Ecosystem structure & function are determined by forcing functions of the system;
  2. Energy inputs to the ecosystems and available storage of the ecosystem is limited;
  3. Ecosystems are open and dissipative systems (not thermodynamic balance of energy, matter, entropy, but spontaneous appearance of complex, chaotic structure);
  4. Attention to a limited number of governing/controlling factors is most strategic in preventing pollution or restoring ecosystems;
  5. Ecosystem have some homeostatic capability that results in smoothing out and depressing the effects of strongly variable inputs;
  6. Match recycling pathways to the rates of ecosystems and reduce pollution effects;
  7. Design for pulsing systems wherever possible;
  8. Ecosystems are self-designing systems;
  9. Processes of ecosystems have characteristic time and space scales that should be accounted for in environmental management;
  10. Biodiversity should be championed to maintain an ecosystem's self design capacity;
  11. Ecotones, transition zones, are as important for ecosystems as membranes for cells;
  12. Coupling between ecosystems should be utilized wherever possible;
  13. The components of an ecosystem are interconnected, interrelated, and form a network; consider direct as well as indirect efforts of ecosystem development;
  14. An ecosystem has a history of development;
  15. Ecosystems and species are most vulnerable at their geographical edges;
  16. Ecosystems are hierarchical systems and are parts of a larger landscape;
  17. Physical and biological processes are interactive, it is important to know both physical and biological interactions and to interpret them properly;
  18. Eco-technology requires a holistic approach that integrates all interacting parts and processes as far as possible;
  19. Information in ecosystems is stored in structures.

Mitsch and Jorgensen identified the following considerations prior implementing an ecological engineering design:

  • Create conceptual model of determine the parts of nature connected to the project;
  • Implement a computer model to simulate the impacts and uncertainty of the project;
  • Optimize the project to reduce uncertainty and increase beneficial impacts.

Relationship to other engineering disciplines

The field of Ecological Engineering is closely related to the fields of environmental engineering and civil engineering. The three broadly overlap in the area of water resources engineering, particularly the treatment and management of stormwater and wastewater. While the three disciplines of engineering are closely related to one another, there are distinct areas of expertise within each field.

Ecological engineering is primarily focused on the natural environment and natural infrastructure, emphasizing the mediation of the relationship between people and planet. In complementary disciplines, civil engineering is primarily focused on built infrastructure and public works while environmental engineering focuses on the protection of public and environmental health through the treatment and management of waste streams.

Relationship between ecological, environmental, and civil engineering.

Academic curriculum (colleges)

An academic curriculum was proposed for ecological engineering in 2001. Key elements of the suggested curriculum are: environmental engineering; systems ecology; restoration ecology; ecological modeling; quantitative ecology; economics of ecological engineering, and technical electives. Complementing this set of courses were prerequisites courses in physical, biological, and chemical subject areas, and integrated design experiences. According to Matlock et al., the design should identify constraints, characterize solutions in ecological time, and incorporate ecological economics in design evaluation. Economics of ecological engineering has been demonstrated using energy principles for a wetland., and using nutrient valuation for a dairy farm. With these principals in mind, the world's first B.S. Ecological Engineering program was formalized in 2009 at Oregon State University.

In 2024, the US Accreditation Board for Engineering and Technology, Inc. (ABET) published criteria for accreditation of Ecological Engineering program for the first time. To be accredited, B.S. Ecological Engineering programs must include:

  • mathematics through differential equations, probability and statistics, calculus-based physics, and college-level chemistry;
  • earth science, fluid mechanics, hydraulics, and hydrology.
  • biological and advanced ecological sciences that focus on multi-organism self-sustaining systems at a range of scales, systems ecology, ecosystem services, and ecological modeling;
  • material and energy balances; fate and transport of substances in and between air, water, and soil; thermodynamics of living systems; and
  • applications of ecological principles to engineering design that include considerations of climate, species diversity, self-organization, uncertainty, sustainability, resilience, interactions between ecological and social systems, and system-scale impacts and benefits.

Visual spatial attention

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Visual_spatial_attention

Visual spatial attention is a form of visual attention that involves directing attention to a location in space. Similar to its temporal counterpart visual temporal attention, these attention modules have been widely implemented in video analytics in computer vision to provide enhanced performance and human interpretable explanation of deep learning models.

Spatial attention allows humans to selectively process visual information through prioritization of an area within the visual field. A region of space within the visual field is selected for attention and the information within this region then receives further processing. Research shows that when spatial attention is evoked, an observer is typically faster and more accurate at detecting a target that appears in an expected location compared to an unexpected location. Attention is guided even more quickly to unexpected locations, when these locations are made salient by external visual inputs (such as a sudden flash). According to the V1 Saliency Hypothesis, the human primary visual cortex plays a critical role for such an exogenous attentional guidance.

Spatial attention is distinctive from other forms of visual attention such as object-based attention and feature-based attention. These other forms of visual attention select an entire object or a specific feature of an object regardless of its location, whereas spatial attention selects a specific region of space and the objects and features within that region are processed.

Measures of visual spatial attention

Spatial cueing experiments

A key property of visual attention is that attention can be selected based on spatial location and spatial cueing experiments have been used to assess this type of selection. In Posner's cueing paradigm, the task was to detect a target that could be presented in one of two locations and respond as quickly as possible. At the start of each trial, a cue is presented that either indicates the location of the target (valid cue) or indicates the incorrect location thus misdirecting the observer (invalid cue). In addition, on some trials there is no information given about the location of the target, as no cue is presented (neutral trials). Two distinct cues were used; the cue was either a peripheral 'flicker' around the target's location (peripheral cue) or the cue was centrally displayed as a symbol, such as an arrow pointing to the location of the target (central cue). Observers are faster and more accurate at detecting and recognising a target if the location of the target is known in advance. Furthermore, misinforming subjects about the location of the target leads to slower reaction times and poorer accuracy relative to performance when no information about the location of the target is given.

Spatial cueing tasks typically assess covert spatial attention, which refers to attention that can change spatially without any accompanying eye movements. To investigate covert attention, it is necessary to ensure that observer's eyes remain fixated at one location throughout the task. In spatial cueing tasks, subjects are instructed to fixate on a central fixation point. Typically it takes 200 ms to make a saccadic eye movement to a location. Therefore, the combined duration of the cue and target is typically presented in less than 200 ms. This ensures that covert spatial attention is being measured and the effects are not due to overt eye movements. Some studies specifically monitor eye movements to ensure that the observer's eyes are continually fixated on the central fixation point.

The central and peripheral cues in spatial cueing experiments can assess the orienting of covert spatial attention. These two cues appear to use different mechanisms for orienting spatial attention. The peripheral cues tend to attract attention automatically, recruiting bottom-up attentional control processes. Conversely, central cues are thought to be under voluntary control and therefore use top-down processes. Studies have shown that peripheral cues are difficult to ignore, as attention is oriented towards the peripheral cue even when the observer knows the cue does not predict the location of the target. Peripheral cues also cause an allocation of attention much faster than central cues, as central cues require greater processing time to interpret the cue.

Spatial probe experiments

In spatial cueing tasks, the spatial probe (cue) causes an allocation of attention to a particular location. Spatial probes have also been often used in other types of tasks to assess how spatial attention is allocated.

Spatial probes have been used to assess spatial attention in visual searches. Visual search tasks involve the detection of a target among a set of distractors. Attention to the location of items in the search can be used to guide visual searches. This was demonstrated by valid cues improving the identification of targets relative to the invalid and neutral conditions. A visual search display can also influence how fast an observer responds to a spatial probe. In a visual search task, a small dot appeared after a visual display and it was found that observers were faster at detecting the dot when it was located at the same location as the target. This demonstrated that spatial attention had been allocated to the target location.

The use of multiple tasks simultaneously in an experiment can also demonstrate the generality of spatial attention, as allocation of attention to one task can influence performance in other tasks. For example, it was found that when attention was allocated to detecting a flickering dot (spatial probe), this increased the likelihood of identifying nearby letters.

Distribution of spatial attention

The distribution of spatial attention has been subject to considerable research. Consequently, this has led to the development of different metaphors and models that represent the proposed spatial distribution of attention.

Spotlight metaphor

According to the 'spotlight' metaphor, the focus of attention is analogous to the beam of a spotlight. The moveable spotlight is directed at one location and everything within its beam is attended and processed preferentially, while information outside the beam is unattended. This suggests that the focus of visual attention is limited in spatial size and moves to process other areas in the visual field.

Zoom-lens metaphor

Research has suggested that the attentional focus is variable in size. Eriksen and St James proposed the 'zoom-lens' metaphor, which is an alternative to the spotlight metaphor and takes into account the variable nature of attention. This account likens the distribution of attention to a zoom-lens that can narrow or widen the focus of attention. This supports findings that show attention can be distributed both over a large area of the visual field and also function in a focused mode. In support of this analogy, research has shown that there is an inverse relationship between the size of the attentional focus and the efficiency of processing within the boundaries of a zoom-lens.

Gradient model

The Gradient Model is an alternative theory on the distribution of spatial attention. This model proposes that attentional resources are allocated in a gradient pattern, with concentrated resources in the centre of focus and resources decrease in a continuous fashion away from the centre. Downing conducted research using an adaptation of Posner's cueing paradigm that supported this model. The target could appear in 12 potential locations, marked by boxes. Results showed that attentional facilitation was strongest at the cued location and gradually decreased with distance away from the cued location. However, not all research has supported the gradient model. For example, Hughes and Zimba  conducted a similar experiment, using a highly distributed visual array and did not use boxes to mark the potential locations of the target. There was no evidence of a gradient effect, as the faster responses were when the cue and target were in the same hemifield and slower responses when they were in different hemifields. The boxes played an important role in attention as a later experiment, used the boxes and consequently found a gradient pattern. Therefore, it is considered that the size of the gradient can adjust according to the circumstances. A broader gradient may be adopted when there is an empty display, as attention can spread and is only restricted by hemifield borders.

Splitting spatial attention

It is debated in research on visual spatial attention whether it is possible to split attention across different areas in the visual field. The 'spotlight' and 'zoom-lens' accounts postulate that attention uses a single unitary focus. Therefore, spatial attention can only be allocated to adjacent areas in the visual field and consequently cannot be split. This was supported by an experiment that altered the spatial cueing paradigm by using two cues, a primary and a secondary cue. It was found that the secondary cue was only effective in focusing attention when its location was adjacent to the primary cue. In addition, it has been demonstrated that observers are unable to ignore stimuli presented in areas situated between two cued locations. These findings have proposed that attention cannot be split across two non-contiguous regions. However, other studies have demonstrated that spatial attention can be split across two locations. For example, observers were able to attend simultaneously to two different targets located in opposite hemifields. Research has even suggested that humans are able to focus attention across two to four locations in the visual field. Another perspective is that spatial attention can be split only under certain conditions. This perspective suggests that the splitting of spatial attention is flexible. Research demonstrated that whether spatial attention is unitary or divided depends on the goals of the task. Therefore, if dividing attention is beneficial to the observer then a divided focus of attention will be utilised.

One of the main difficulties in establishing whether spatial attention can be divided is that a unitary focus model of attention can also explain a number of the findings. For example, when two non-contiguous locations are attended to, it may not be that attention has been split between these two locations but instead it may be that the unitary focus of attention has expanded. Alternatively, the two locations may not be attended to simultaneously and instead the area of focus is moving quickly from one location to another. Consequently, it appears very difficult to prove undoubtedly that spatial attention can be split.

Deficits in visual spatial attention

Hemineglect

Hemineglect, also known as unilateral visual neglect, attentional neglect, hemispatial neglect or spatial neglect, is a disorder incorporating a significant deficit in visuospatial attention. Hemineglect refers to the inability of patients with unilateral brain damage to detect objects in the side of space contralateral to the lesion (contralesional); i.e. damage to the right cerebral hemisphere resulting in neglect of objects on the left side of space, and is characterized by hemispheric asymmetry. Performance is generally preserved in the side ipsilateral to the lesion (ipsilesional). Hemineglect is more frequent and arguably more severe following damage to the right cerebral hemisphere of right-handed subjects. It has been proposed that the right parietal lobes are comparatively more responsible for the allocation of spatial attention, therefore damage to this hemisphere often produces more severe effects. Additionally, it is difficult to map with accuracy the visual sensory deficits in the neglected hemifield.

Neglect is diagnosed using a variety of paper-and-pencil tasks. A common method is the Complex Figure Test (CFT). The CFT requires patients to copy a complicated line drawing, and then reproduce it from memory. Often patients will neglect features present on the contralesional side of space and objects. Patients with neglect will perform similarly when reproducing mental images of familiar places and objects. A common error is the failure to include numbers on the left side of a picture when drawing an analogue clock from memory, for example, all of the numbers may be positioned on the right side of the clock face.

Another paper-and-pencil task is the line bisection task. In this exercise, patients are required to divide a horizontal line halfway along. Patients with neglect will often bisect the line to the right of the true centre, leaving the left portion of the line unattended to.

Object cancellation tasks are also used to determine the extent of potential deficit. During this task, patients are required to cancel out (cross out) all of the objects in a cluttered display (e.g. lines, geometric shapes, letters, etc.). Patients with damage primarily to the right parietal area fail in the detection of objects in the left visuospatial field, and these are often not crossed out by the patient. In addition, those patients who may be severely affected tend to fail in detecting their errors on visual inspection.

Extinction

Extinction is a phenomenon observable during double simultaneous stimulation of both left and right visual fields. Patients with extinction will fail to perceive the stimulus in the contralesional visual field when presented in conjunction with a stimulus in the ipsilesional field. However, when presented on its own, patients can correctly perceive the contralesional stimulus. Thus, patients with neglect fail to report stimuli present in the aberrant field, whereas patients with extinction fail to report stimuli in the aberrant field only when double simultaneous presentations occur in both hemifields. Analogous to neglect, extinction affects the contralesional visuospatial field in majority of patients with unilateral damage. Anatomical correlates of visuospatial neglect and extinction do not overlap absolutely, with extinction proposed to be associated with subcortical lesions.

A common method in quick detection of visuospatial extinction is a Finger Confrontation Model. Utilized as standard bedside evaluation, the task requires the patient to indicate (either verbally or by pointing) in which visual field the doctor's hand or finger is moving, while the doctor makes a wiggling motion with his index. This enables the doctor to distinguish between deficits resembling neglect and those which may indicate extinction, by presenting either a single stimulus in the contralesional field or two simultaneous stimuli in both the contralesional and ipsilesional visual fields. This quick test can be used immediately in a hospital setting for quick diagnosis, and can be particularly useful following strokes and seizures.

Regions associated with impairment of visuospatial attention

Parietal damage

The posterior parietal region is arguably the most extensively studied in relation to visuospatial attention. Patients with parietal lobe damage most often fail to attend to stimuli located on the contralesional hemisphere, as seen in patients with hemineglect/unilateral visual neglect. As such, they may fail to acknowledge a person sitting to their left, they may neglect to eat food positioned on their left, or make head or eye movements to the left. Computed tomography (CT) studies have demonstrated that the inferior parietal lobule in the right hemisphere is the most frequently damaged in patients with severe neglect.

Parietal damage may decrease the ability to reduce decision noise. Spatial cues appear to reduce the uncertainty of a visuospatial decision. Disruption to spatial orienting, as seen in hemineglect, suggests that patients with damage to the parietal region may experience an increased difficulty in decision-making regarding targets located in the contralesional field.

Damage to the parietal region may also increase illusory conjunctions of features. Illusory conjunctions occur when people report combinations of features which did not occur. For example, when presented with an orange square and a purple circle, the participant may report a purple square or an orange circle. Although it would typically require special circumstances for a non-impaired person to produce an illusory conjunction, it appears that some patients with damage to the parietal cortex may demonstrate a vulnerability to such visuospatial impairments. Results from parietal patients suggest that the parietal cortex, and therefore spatial attention, may be implicated in solving this problem of binding features.

Frontal lobe damage

Lesions to the frontal cortices have long been known to precede spatial neglect and other visuospatial deficits. Specifically, frontal lobe damage has been associated with a deficit in the control of over attention (the production of eye movements). Lesions to the superior frontal lobe areas that include the frontal eye fields seem to disrupt some forms of overt eye movements. It has been demonstrated by Guitton, Buchtel, & Douglas that eye movement directed away from an abruptly appearing visual target ("antisaccade") is remarkably impaired in patients with damage to the frontal eye fields, who frequently made reflexive eye movements to the target. When frontal eye field patients did make antisaccades, they had increased latency of their eye movements compared to controls. This suggests that the frontal lobes, specifically the dorsolateral region containing the frontal eye fields, play an inhibitory role in preventing reflexive eye movements in overt attention control. Further, the frontal eye fields or surrounding areas may be critically associated with neglect following dorsolateral frontal lesions.

Frontal lobe lesions also appear to produce deficits in visuospatial attention related to covert attention (the orienting of attention without the requirement eye movement). Using Posner's Spatial Cueing Task, Alivesatos and Milner found that participants with frontal lobe damage demonstrated a comparably smaller attentional benefit from the valid cues than control participants or participants with temporal lobe damage. Voluntary orienting of frontal lobe patients appear to be impaired.

The right lateral frontal lobe region was also found to be associated with left-sided visual neglect in an investigation carried out by Husain & Kennard. A region of overlap was found in the location of lesions in four of five patients with left-sided visual neglect, specifically the dorsal aspect of the inferior frontal gyrus and the underlying white matter. Additionally, overlap of lesion areas was also detected in the dorsal region of Brodmann area 44 (anterior to the premotor cortex). These results further implicate the frontal lobe in directing attention in visual space.

Thalamic nuclei damage (pulvinar nucleus)

The thalamic nuclei have been speculated to be involved in directing attention to locations in visual space. Specifically, the pulvinar nucleus appears to be implicated in the subcortical control of spatial attention, and lesions in this area can cause neglect. Evidence suggests that the pulvinar nucleus of the thalamus might be responsible for engaging in spatial attention at a previously cued location. A study by Rafal and Posner found that patients who had acute pulvinar lesions were slower to detect a target which appeared in the contralesional visuospatial field compared to the appearance of a target in the ipsilesional field during a spatial cuing task. This suggests a deficit in the ability to use attention to improve performance in detection and processing of visual targets in the contralesional region.

Use in camouflage

Camouflage relies on deceiving the cognition of the observer, such as a predator. Some camouflage mechanisms such as distractive markings likely function by competing for visual attention with stimuli that would give away the presence of the camouflaged object (such as a prey animal). Such markings have to be conspicuous, and positioned away from the outline so as to avoid drawing attention to it, in contrast to disruptive markings which work best when in contact with the outline.

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