A number of other major international human rights instruments
contain provisions relating to economic, social and cultural rights. The
Convention on the Rights of the Child
recognizes and protects many of the economic, social and cultural
rights recognized in the ICESCR in relation to children. Including the right to health in Article 24, the right to social security in Article 25, the right to an adequate standard of living in Article 27, the right to education in Article 28, and the right to protection from economic exploitation (see child labour) in Article 32. The Convention on the Elimination of All Forms of Racial Discrimination
prohibits discrimination on the basis of racial or ethnic origin in
relation to a number of economic, social and cultural rights. The Convention on the Elimination of All Forms of Discrimination Against Women affirms a range of economic, social and cultural rights to women. The ILO Conventions of the International Labour Organization (ILO) protect a range of work related economic, social and cultural rights.
Common global standards were agreed by some 195 states in the
Recommendation on Science and Scientific protect and reassert scientific
freedoms, the rights of scientists, and rights of research subjects, and the right of everyone to science.
A
range of secondary legal sources exist on economic, social and cultural
rights which provide guidance on their normative definition. An
important secondary legal source is the United Nations Committee on Economic, Social and Cultural Rights which is overseeing the implementation of the International Covenant on Economic, Social and Cultural Rights
(ICESCR). The Committee has been central in developing the normative
definition of key economic, social and cultural rights, interpreting the
role of State Parties to the ICESCR, and monitoring protection and
violation of the ICESCR rights. The Committee issues guiding
pronouncements in the form of general comments, and other human rights treaty bodies may also issue comments relevant to economic, social and cultural rights.
Other important secondary legal sources on economic, social and
cultural rights are the Limburg Principles on the Implementation of the
International Covenant on Economic, Social and Cultural Rights 1987 and
the Maastricht Guidelines on Violations of Economic, Social and Cultural Rights
1997. The Limburg Principles have been extensively used in national
legal systems as an interpretive tool for establishing violations of
economic, social and cultural rights. The Maastricht
Guidelines build on the Limburg Principles and identify the legal
implications of acts and omissions which are violations of economic,
social and cultural rights. Various United Nations Special Rapporteurs have influenced the normative development of economic, social and cultural rights. Appointed by the Commission on Human Rights
and its sub-commissions, key rapporteurs include the Special Rapporteur
on the Realization of Economic, Social and Cultural Rights, the Special
Rapporteur on the Right to Adequate Housing, the Special Rapporteur on
the Right to Education, and the Special Rapporteur on Violence Against Women.
National constitutions
A number of national constitutions recognize economic, social and cultural rights. For example, the 1996 Constitution of South Africa includes economic, social and cultural rights and the South African Constitutional Court has heard claims under these obligations (see Grootboom and Treatment Action Campaign cases). The Supreme Court of India has interpreted Article 21 of the Constitution to contain positive social rights.
Constitutional recognition of economic, social and cultural
rights has long been thought to be counterproductive, given that courts
might be tasked to adjudicate them, and hence disrupt the democratic chains of accountability of the so-called elected branches. Nonetheless, a growing literature from the Global South has tracked very different judicial responses.
Sympathetic critics argue that socio-economic rights appear
'quite negligible' factors in terms of ensuring overall human
development. Contemporary welfare states tend to emphasize decommodification, general welfare and the common good,
not rights. Sweden, Finland, and Denmark, for example, adhere to a
comparatively robust welfare effort, built primarily through social
democratic parties and trade union mobilisation, without relying on
judicial review of socio-economic rights.
Nonetheless, majoritarian political arenas such as parliaments and
trade union structures may remain unresponsive to minorities. The gains
won through litigation, modest though they may be, can nonetheless be of
value for those who benefit from them.
Civil society movements have advanced alternative institutions,
norms and practices for constitution-making and making socio-economic
rights effective. Participants in recent constitution-making experiments
in Iceland, Bolivia and Ecuador have all linked economic and social rights to new institutional arrangements such as participatory budgeting or technologically-enhanced direct democracy as well as to new norms and discourses, notably those concerning ecological stewardship and the commons as well as care and social reproduction. In Ireland, social movements such as the 'Right2Water' and 'Repeal the 8th' campaigns have demonstrated how highly networked
individuals and communities can mobilise both alongside and outside of
traditional institutions, act collectively, and advance economic, social
and cultural rights.
State parties to the ICESCR are required to take "progressive
action" towards fulfilment of the ICESR rights. While immediate
fulfilment may not be possible due to the economic situation of a
country, postponement of proactive action is not permitted. State
parties must show genuine efforts to secure the economic, social and
cultural rights enshrined in the ICESCR. The burden of proof for
progressive action is considered on be with the state party. The
prohibition on discrimination
in relation to economic, social and cultural rights is regarded as
having immediate effect. State parties must abolish laws, policies and
practices which affect the equal enjoyment of economic, social and
cultural rights and take action to prevent discrimination in public
life. All state parties, regardless of the economic situation in the
country or resource scarcity, are required to ensure respect for minimum
subsistence rights for all. State parties must also ensure that
available resources are accessed and used equitably. Therefore,
government decisions on how to allocate resources should be subject to
scrutiny. Legislative measures alone are not sufficient to ensure
compliance with the ICESCR and state parties are expected to provide
judicial remedies in addition to taking administrative, financial,
educational and social measures.
Monitoring, enforcement and implementation framework
Intergovernmental organisations and non-governmental organisations (NGOs) have persistently neglected economic, social and cultural rights over the past 50 years.
While all human rights are said to be "equal, indivisible,
interrelated, and interdependent", the monitoring, enforcement and
implementation framework for economic, social and cultural rights is
less advanced than that for civil and political rights.
International enforcement mechanisms are strongest for civil and
political rights, and their violation is considered more serious than
that of economic, social and cultural rights. There are few
international NGOs that focus on economic, social and cultural rights
and there are few lawyers who have the knowledge or experience to defend
economic, social and cultural rights at a national or international
level. Economic, social and cultural rights are less likely than civil
and political rights to be protected in national constitutions.
In 2017, for the common global standards in the Recommendation on
Science and Scientific Researchers relating to the right to science,
states agreed at the UNESCO General Conference to adopt four-yearly
reporting on implementation, and agreed that UNESCO's Executive Board is
competent to manage monitoring, with the networks of UNESCO National
Commissions and academic partners mobilized in countries to ensure
implementation and monitoring at country level.
For the other major international human rights conventions mentioned
above there are various other treaty bodies to ensure some monitoring of
implementation. And each may transmit to the Human Rights Council
reports of individual cases when a state is the subject of a Universal
Periodic Review.
The right to education places the individual at the centre of education frameworks.
Education as a human right has the following characteristics:
It is a right; Education is not a privilege or subject to
political or charitable whims. It is a human right. It places mandatory
demands on duty-bearers (particularly the state, but also parents,
children, and other actors).
It is high priority; Education is a key priority of the state. Obligations to ensure the right to education cannot be dismissed.
It is a key right; Education is instrumental in ensuring all other human rights. It has economic, social, cultural, civil, and political dimensions.[18]
The right to education places legal obligations
on states when they make decisions regarding education and the
education system. It offers an internationally agreed normative
framework for the standards that states must not fall beneath concerning
the education of its citizens and non-citizens.
Education as a multiplier right
These standards define what states must do and avoid doing in order to ensure the dignity
of the individual. The right to education is broad and covers many
aspects of education. This means that for the specific areas related to
education, states must act within the boundaries permitted under international human rights law (IHRL).
Networking groups such as ESCR-Net
are working to create online resources and spread information about
effective cases, initiatives, and working groups promoting ideals and
celebrating victories of human rights initiatives and the Optional Protocol to the International Covenant on Economic, Social and Cultural Rights.
Currently, human rights advocacy groups are working diligently to
fine-tune rules, regulations and implementation schemes; little news of
complaint successes or failures is available. The Centre on Housing Rights and Evictions (COHRE) has helped to establish the Housing and Property Directorate (HPD/HPCC) in Kosovo.
The study of time perception or chronoception is a field within psychology, cognitive linguistics and neuroscience that refers to the subjective experience, or sense, of time, which is measured by someone's own perception of the duration of the indefinite and unfolding of events. The perceived time interval between two successive events is referred to as perceived duration.
Though directly experiencing or understanding another person's
perception of time is not possible, perception can be objectively
studied and inferred
through a number of scientific experiments. Some temporal illusions
help to expose the underlying neural mechanisms of time perception.
The ancient Greeks recognized the difference between chronological time (chronos) and subjective time (Kairos).
Pioneering work on time perception, emphasizing species-specific differences, was conducted by Karl Ernst von Baer.
Theories
Time
perception is typically categorized in three distinct ranges, because
different ranges of duration are processed in different areas of the
brain:
Sub-second timing or millisecond timing
Interval timing or seconds-to-minutes timing
Circadian timing
There are many theories and computational models for time perception
mechanisms in the brain. William J. Friedman (1993) contrasted two
theories of the sense of time:
The strength model of time memory. This posits a memory trace
that persists over time, by which one might judge the age of a memory
(and therefore how long ago the event remembered occurred) from the
strength of the trace. This conflicts with the fact that memories of
recent events may fade more quickly than more distant memories.
The inference model suggests the time of an event is inferred
from information about relations between the event in question and
other events whose date or time is known.
Another hypothesis involves the brain's subconscious tallying of
"pulses" during a specific interval, forming a biological stopwatch.
This theory proposes that the brain can run multiple biological
stopwatches independently depending on the type of tasks being tracked.
The source and nature of the pulses is unclear. They are as yet a metaphor whose correspondence to brain anatomy or physiology is unknown.
The specious present is the time duration wherein a state of consciousness is experienced as being in the present. The term was first introduced by the philosopher E. R. Clay in 1882 (E. Robert Kelly), and was further developed by William James.
James defined the specious present to be "the prototype of all
conceived times... the short duration of which we are immediately and
incessantly sensible". In "Scientific Thought" (1930), C. D. Broad
further elaborated on the concept of the specious present and
considered that the specious present may be considered as the temporal
equivalent of a sensory datum. A version of the concept was used by Edmund Husserl in his works and discussed further by Francisco Varela based on the writings of Husserl, Heidegger, and Merleau-Ponty.
Although the perception of time is not associated with a specific sensory system, psychologists and neuroscientists suggest that humans do have a system, or several complementary systems, governing the perception of time. Time perception is handled by a highly distributed system involving the cerebral cortex, cerebellum and basal ganglia. One particular component, the suprachiasmatic nucleus, is responsible for the circadian (or daily) rhythm, while other cell clusters appear to be capable of shorter (ultradian)
timekeeping. There is some evidence that very short (millisecond)
durations are processed by dedicated neurons in early sensory parts of
the brain.
Warren Meck
devised a physiological model for measuring the passage of time. He
found the representation of time to be generated by the oscillatory
activity of cells in the upper cortex. The frequency of these cells' activity is detected by cells in the dorsal striatum at the base of the forebrain. His model separated explicit timing and implicit timing. Explicit timing is used in estimating the duration of a stimulus.
Implicit timing is used to gauge the amount of time separating one from
an impending event that is expected to occur in the near future. These
two estimations of time do not involve the same neuroanatomical areas.
For example, implicit timing often occurs to achieve a motor task,
involving the cerebellum, left parietal cortex, and left premotor cortex. Explicit timing often involves the supplementary motor area and the right prefrontal cortex.
Two visual stimuli, inside someone's field of view, can be successfully regarded as simultaneous up to five milliseconds.
In the popular essay "Brain Time", David Eagleman
explains that different types of sensory information (auditory,
tactile, visual, etc.) are processed at different speeds by different
neural architectures. The brain must learn how to overcome these speed
disparities if it is to create a temporally unified representation of
the external world:
if the visual brain wants to get
events correct timewise, it may have only one choice: wait for the
slowest information to arrive. To accomplish this, it must wait about a
tenth of a second. In the early days of television broadcasting,
engineers worried about the problem of keeping audio and video signals
synchronized. Then they accidentally discovered that they had around a
hundred milliseconds of slop: As long as the signals arrived within this
window, viewers' brains would automatically resynchronize the signals.
He goes on to say, "This brief waiting period allows the visual system
to discount the various delays imposed by the early stages; however, it
has the disadvantage of pushing perception into the past. There is a
distinct survival advantage to operating as close to the present as
possible; an animal does not want to live too far in the past.
Therefore, the tenth-of-a-second window may be the smallest delay that
allows higher areas of the brain to account for the delays created in
the first stages of the system while still operating near the border of
the present. This window of delay means that awareness is retroactive,
incorporating data from a window of time after an event and delivering a
delayed interpretation of what happened."
Experiments have shown that rats can successfully estimate a time interval of approximately 40 seconds, despite having their cortex entirely removed. This suggests that time estimation may be a low level process.
Ecological perspectives
In recent history, ecologists and psychologists have been interested in whether and how time is perceived by non-human animals, as well as which functional purposes are served by the ability to perceive time. Studies have demonstrated that many species of animals, including both vertebrates and invertebrates, have cognitive abilities that allow them to estimate and compare time intervals and durations in a similar way to humans.
There is empirical evidence that metabolic rate has an impact on animals' ability to perceive time. In general, it is true within and across taxa that animals of smaller size (such as flies), which have a fast metabolic rate, experience time more slowly than animals of larger size, which have a slow metabolic rate.
Researchers suppose that this could be the reason why small-bodied
animals are generally better at perceiving time on a small scale, and
why they are more agile than larger animals.
Time perception in vertebrates
Examples in fish
In a lab experiment, goldfish were conditioned to receive a light stimulus followed shortly by an aversiveelectric shock,
with a constant time interval between the two stimuli. Test subjects
showed an increase in general activity around the time of the electric
shock. This response persisted in further trials in which the light
stimulus was kept but the electric shock was removed.
This suggests that goldfish are able to perceive time intervals and to
initiate an avoidance response at the time when they expect the
distressing stimulus to happen.
In two separate studies, golden shiners and dwarf inangas demonstrated the ability to associate the availability of food sources to specific locations and times of day, called time-place learning. In contrast, when tested for time-place learning based on predation risk, inangas were unable to associate spatiotemporal patterns to the presence or absence of predators.
When
presented with the choice between obtaining food at regular intervals
(with a fixed delay between feedings) or at stochastic intervals (with a
variable delay between feedings), starlings
can discriminate between the two types of intervals and consistently
prefer getting food at variable intervals. This is true whether the
total amount of food is the same for both options or if the total amount
of food is unpredictable in the variable option. This suggests that
starlings have an inclination for risk-prone behavior.
Pigeons are able to discriminate between different times of day and show time-place learning.
After training, lab subjects were successfully able to peck specific
keys at different times of day (morning or afternoon) in exchange for
food, even after their sleep/wake cycle was artificially shifted. This
suggests that to discriminate between different times of day, pigeons
can use an internal timer (or circadian timer) that is independent of external cues.
However, a more recent study on time-place learning in pigeons suggests
that for a similar task, test subjects will switch to a non-circadian
timing mechanism when possible to save energy resources.
Experimental tests revealed that pigeons are also able to discriminate
between cues of various durations (on the order of seconds), but that
they are less accurate when timing auditory cues than when timing visual cues.
Examples in mammals
A study on privately owned dogs revealed that dogs
are able to perceive durations ranging from minutes to several hours
differently. Dogs reacted with increasing intensity to the return of
their owners when they were left alone for longer durations, regardless
of the owners' behavior.
After being trained with food reinforcement, female wild boars
are able to correctly estimate time intervals of days by asking for
food at the end of each interval, but they are unable to accurately
estimate time intervals of minutes with the same training method.
When trained with positive reinforcement, rats
can learn to respond to a signal of a certain duration, but not to
signals of shorter or longer durations, which demonstrates that they can
discriminate between different durations.
Rats have demonstrated time-place learning, and can also learn to infer
correct timing for a specific task by following an order of events,
suggesting that they might be able to use an ordinal timing mechanism. Like pigeons, rats are thought to have the ability to use a circadian timing mechanism for discriminating time of day.
Time perception in invertebrates
Forager honey bee flying back to the hive with pollen and nectar
When returning to the hive with nectar, foragerhoney bees
need to know the current ratio of nectar-collecting to
nectar-processing rates in the colony. To do so, they estimate the time
it takes them to find a food-storer bee, which will unload the forage
and store it. The longer it takes them to find one, the busier the
food-storer bees are; and therefore the higher the nectar-collecting
rate of the colony. Forager bees also assess the quality of nectar by comparing the length of time it takes to unload the forage:
a longer unloading time indicates higher quality nectar. They compare
their own unloading time to the unloading time of other foragers present
in the hive, and adjust their recruiting behavior accordingly. For instance, honey bees reduce the duration of their waggle dance if they judge their own yield to be inferior. Scientists have demonstrated that anesthesia disrupts the circadian clock and impairs the time perception of honey bees, as observed in humans. Experiments revealed that a 6-hour-long general anesthesia
significantly delayed the start of the foraging behaviour of honeybees
if induced during daytime, but not if induced during nighttime.
Bumble bees can be successfully trained to respond to a stimulus
after a certain time interval has elapsed (usually several seconds
after the start signal). Studies have shown that they can also learn to
simultaneously time multiple interval durations.
In a single study, colonies from three species of ants from the genus Myrmica
were trained to associate feeding sessions with different times. The
trainings lasted several days, where each day the feeding time was
delayed by 20 minutes compared to the previous day. In all three
species, at the end of the training, most individuals were present at
the feeding spot at the correct expected times, suggesting that ants are
able to estimate the time running, keep in memory the expected feeding
time and to act anticipatively.
Types of temporal illusions
A temporal illusion is a distortion in the perception of time. For example:
estimating time intervals, e.g., "When did you last see your primary care physician?";
estimating time duration, e.g., "How long were you waiting at the doctor's office?"; and
judging the simultaneity of events (see below for examples).
Main types of temporal illusions
Telescoping effect:
People tend to recall recent events as occurring further back in time
than they actually did (backward telescoping) and distant events as
occurring more recently than they actually did (forward telescoping).
Vierordt's law: Shorter intervals tend to be overestimated while longer intervals tend to be underestimated
Time intervals associated with more changes may be perceived as longer than intervals with fewer changes
Perceived temporal length of a given task may shorten with greater motivation
Perceived temporal length of a given task may stretch when broken up or interrupted
Auditory stimuli may appear to last longer than visual stimuli
Time durations may appear longer with greater stimulus intensity (e.g., auditory loudness or pitch)
Simultaneity judgments can be manipulated by repeated exposure to non-simultaneous stimuli
Kappa effect
The Kappa effect or perceptual time dilation is a form of temporal illusion verifiable by experiment.[57]
The temporal duration between a sequence of consecutive stimuli is
thought to be relatively longer or shorter than its actual elapsed time,
due to the spatial/auditory/tactile separation between each consecutive
stimuli. The kappa effect can be displayed when considering a journey
made in two parts that each take an equal amount of time. When mentally
comparing these two sub-journeys, the part that covers more distance may appear to take longer than the part covering less distance, even though they take an equal amount of time.
Eye movements and "Chronostasis"
The perception of space and time undergoes distortions during rapid saccadic eye movements.
Chronostasis
is a type of temporal illusion in which the first impression following
the introduction of a new event or task demand to the brain appears to
be extended in time. For example, chronostasis temporarily occurs when fixating on a target stimulus, immediately following a saccade (e.g., quick eye movement).
This elicits an overestimation in the temporal duration for which that
target stimulus (i.e., postsaccadic stimulus) was perceived. This effect
can extend apparent durations by up to 500 ms and is consistent with
the idea that the visual system models events prior to perception. The most well-known version of this illusion is known as the stopped-clock illusion,
wherein a subject's first impression of the second-hand movement of an
analog clock, subsequent to one's directed attention (i.e., saccade) to
the clock, is the perception of a slower-than-normal second-hand
movement rate (the seconds hand of the clock may seemingly temporarily
freeze in place after initially looking at it).
The occurrence of chronostasis extends beyond the visual domain into the auditory and tactile domains.
In the auditory domain, chronostasis and duration overestimation occur
when observing auditory stimuli. One common example is a frequent
occurrence when making telephone calls. If, while listening to the
phone's dial tone, research subjects move the phone from one ear to the
other, the length of time between rings appears longer.
In the tactile domain, chronostasis has persisted in research subjects
as they reach for and grasp objects. After grasping a new object,
subjects overestimate the time in which their hand has been in contact
with this object.
In an experiment, participants were told to stare at an "x" symbol on
a computer screen whereby a moving blue doughnut-like ring repeatedly
circled the fixed "x" point.
Occasionally, the ring would display a white flash for a split second
that physically overlapped the ring's interior. However, when asked what
was perceived, participants responded that they saw the white flash
lagging behind the center of the moving ring. In other words, despite
the reality that the two retinal images were actually spatially aligned,
the flashed object was usually observed to trail a continuously moving
object in space — a phenomenon referred to as the flash-lag effect.
The first proposed explanation, called the "motion extrapolation" hypothesis, is that the visual system extrapolates
the position of moving objects but not flashing objects when accounting
for neural delays (i.e., the lag time between the retinal image and the
observer's perception of the flashing object). The second proposed
explanation by David Eagleman and Sejnowski, called the "latency
difference" hypothesis, is that the visual system processes moving
objects at a faster rate than flashed objects. In the attempt to
disprove the first hypothesis, David Eagleman conducted an experiment in
which the moving ring suddenly reverses direction to spin in the other
way as the flashed object briefly appears. If the first hypothesis were
correct, we would expect that, immediately following reversal, the
moving object would be observed as lagging behind the flashed object.
However, the experiment revealed the opposite — immediately following
reversal, the flashed object was observed as lagging behind the moving
object. This experimental result supports the "latency difference"
hypothesis. A recent study tries to reconcile these different approaches
by treating perception as an inference mechanism aiming at describing
what is happening at the present time.
Oddball effect
Humans typically overestimate the perceived duration of the initial and final event in a stream of identical events.
This oddball effect may serve an evolutionarily adapted
"alerting" function and is consistent with reports of time slowing down
in threatening situations. The effect seems to be strongest for images
that are expanding in size on the retina, in other words, that are
"looming" or approaching the viewer, and the effect can be eradicated for oddballs that are contracting or perceived to be receding from the viewer. The effect is also reduced or reversed with a static oddball presented among a stream of expanding stimuli.
Initial studies suggested that this oddball-induced "subjective
time dilation" expanded the perceived duration of oddball stimuli by
30–50% but subsequent research has reported more modest expansion of around 10% or less.
The direction of the effect, whether the viewer perceives an increase
or a decrease in duration, also seems to be dependent upon the stimulus
used.
Reversal of temporal order judgment
Numerous
experimental findings suggest that temporal order judgments of actions
preceding effects can be reversed under special circumstances.
Experiments have shown that sensory simultaneity judgments can be
manipulated by repeated exposure to non-simultaneous stimuli. In an
experiment conducted by David Eagleman,
a temporal order judgment reversal was induced in subjects by exposing
them to delayed motor consequences. In the experiment, subjects played
various forms of video games. Unknown to the subjects, the experimenters
introduced a fixed delay between the mouse movements and the subsequent
sensory feedback. For example, a subject may not see a movement
register on the screen until 150 milliseconds after they had moved the
mouse. Participants playing the game quickly adapted to the delay and
felt as though there was less delay between their mouse movement and the
sensory feedback. Shortly after the experimenters removed the delay,
the subjects commonly felt as though the effect on the screen happened
just before they commanded it. This work addresses how the perceived
timing of effects is modulated by expectations, and the extent to which
such predictions are quickly modifiable.
In an experiment conducted by Haggard and colleagues in 2002,
participants pressed a button that triggered a flash of light at a
distance, after a slight delay of 100 milliseconds.
By repeatedly engaging in this act, participants had adapted to the
delay (i.e., they experienced a gradual shortening in the perceived time
interval between pressing the button and seeing the flash of light).
The experimenters then showed the flash of light instantly after the
button was pressed. In response, subjects often thought that the flash
(the effect) had occurred before the button was pressed (the cause).
Additionally, when the experimenters slightly reduced the delay, and
shortened the spatial distance between the button and the flash of
light, participants had often claimed again to have experienced the
effect before the cause.
Several experiments also suggest that temporal order judgment of a pair of tactile
stimuli delivered in rapid succession, one to each hand, is noticeably
impaired (i.e., misreported) by crossing the hands over the midline.
However, congenitally blind subjects showed no trace of temporal order
judgment reversal after crossing the arms. These results suggest that
tactile signals taken in by the congenitally blind are ordered in time
without being referred to a visuospatial representation. Unlike the
congenitally blind subjects, the temporal order judgments of the
late-onset blind subjects were impaired when crossing the arms to a
similar extent as non-blind subjects. These results suggest that the
associations between tactile signals and visuospatial representation is
maintained once it is accomplished during infancy. Some research studies
have also found that the subjects showed reduced deficit in tactile
temporal order judgments when the arms were crossed behind their back
than when they were crossed in front.
Physiological associations
Tachypsychia
Tachypsychia is a neurological condition that alters the perception of time, usually induced by physical exertion, drug use, or a traumatic event. For someone affected by tachypsychia, time perceived by the individual either lengthens, making events appear to slow down, or contracts, with objects appearing as moving in a speeding blur.
Effects of emotional states
Awe
Research has suggested the feeling of awe
has the ability to expand one's perceptions of time availability. Awe
can be characterized as an experience of immense perceptual vastness
that coincides with an increase in focus. Consequently, it is
conceivable that one's temporal perception would slow down when
experiencing awe. The perception of time can differ as people choose between savoring moments and deferring gratification.
Fear
Possibly related to the oddball effect,
research suggests that time seems to slow down for a person during
dangerous events (such as a car accident, a robbery, or when a person
perceives a potential predator or mate), or when a person skydives or bungee jumps, where they're capable of complex thoughts in what would normally be the blink of an eye (See Fight-or-flight response).
This reported slowing in temporal perception may have been
evolutionarily advantageous because it may have enhanced one's ability
to intelligibly make quick decisions in moments that were of critical importance to our survival.
However, even though observers commonly report that time seems to have
moved in slow motion during these events, it is unclear whether this is a
function of increased time resolution during the event, or instead an
illusion created by the remembering of an emotionally salient event.
A strong time dilation effect has been reported for perception of
objects that were looming, but not of those retreating, from the
viewer, suggesting that the expanding discs — which mimic an approaching
object — elicit self-referential processes which act to signal the presence of a possible danger. Anxious people, or those in great fear, experience greater "time dilation" in response to the same threat stimuli due to higher levels of epinephrine, which increases brain activity (an adrenaline rush). In such circumstances, an illusion of time dilation could assist an effective escape. When exposed to a threat, three-year-old children were observed to exhibit a similar tendency to overestimate elapsed time.
Research suggests that the effect appears only at the point of
retrospective assessment, rather than occurring simultaneously with
events as they happened. Perceptual abilities were tested during a frightening experience — a free fall
— by measuring people's sensitivity to flickering stimuli. The results
showed that the subjects' temporal resolution was not improved as the
frightening event was occurring. Events appear to have taken longer only
in retrospect, possibly because memories were being more densely packed
during the frightening situation.
Other researchers
suggest that additional variables could lead to a different state of
consciousness in which altered time perception does occur during an
event. Research does demonstrate that visual sensory processing
increases in scenarios involving action preparation. Participants
demonstrated a higher detection rate of rapidly presented symbols when
preparing to move, as compared to a control without movement.
People shown extracts from films known to induce fear
often overestimated the elapsed time of a subsequently presented visual
stimulus, whereas people shown emotionally neutral clips (weather
forecasts and stock market updates) or those known to evoke feelings of
sadness showed no difference. It is argued that fear prompts a state of
arousal in the amygdala,
which increases the rate of a hypothesized "internal clock". This could
be the result of an evolved defensive mechanism triggered by a
threatening situation.
Individuals experiencing sudden or surprising events, real or imagined
(e.g., witnessing a crime, or believing one is seeing a ghost), may
overestimate the duration of the event.
Changes with age
Psychologists
have found that the subjective perception of the passing of time tends
to speed up with increasing age in humans. This often causes people to
increasingly underestimate a given interval of time as they age. This
fact can likely be attributed to a variety of age-related changes in the
aging brain, such as the lowering in dopaminergic levels with older age; however, the details are still being debated.
Very young children will first experience the passing of time
when they can subjectively perceive and reflect on the unfolding of a
collection of events. A child's awareness of time develops during
childhood, when the child's attention and short-term memory capacities
form — this developmental process is thought to be dependent on the slow
maturation of the prefrontal cortex and hippocampus.
The common explanation is that most external and internal
experiences are new for young children but repetitive for adults.
Children have to be extremely engaged (i.e. dedicate many neural
resources or significant brain power) in the present moment because they
must constantly reconfigure their mental models of the world to
assimilate it and manage behaviour properly.
Adults, however, may rarely need to step outside mental habits
and external routines. When an adult frequently experiences the same
stimuli, such stimuli may seem "invisible" as a result of having already
been sufficiently mapped by the brain. This phenomenon is known as neural adaptation. Thus, the brain will record fewer densely rich memories during these frequent periods of disengagement from the present moment. Consequently, the subjective perception is often that time passes by at a faster rate with age.
Proportional to the real time
Let S be subjective time, R be real time, and define both to be zero at birth.
One model proposes that the passage of subjective time relative to actual time is inversely proportional to real time:
When solved, .
One day would be approximately 1/4,000 of the life of an
11-year-old, but approximately 1/20,000 of the life of a 55-year-old.
This helps to explain why a random, ordinary day may therefore appear
longer for a young child than an adult. So a year would be experienced
by a 55-year-old as passing approximately 5 times more quickly than a
year experienced by an 11-year-old. If long-term time perception is
based solely on the proportionality
of a person's age, then the following four periods in life would appear
to be quantitatively equal: ages 5–10 (1x), ages 10–20 (2x), ages 20–40
(4x), age 40–80 (8x), as the end age is twice the start age. However,
this does not work for ages 0–10, which corresponds to ages 10–∞.
Proportional to the subjective time
Lemlich
posits that the passage of subjective time relative to actual time is
inversely proportional to total subjective time, rather than the total
real time:
When mathematically solved,
It avoids the issue of infinite subjective time passing from real age 0 to 1 year, as the asymptote can be integrated in an improper integral. Using the initial conditions S = 0 when R = 0 and K > 0,
This means that time appears to pass in proportion to the square root
of the perceiver's real age, rather than directly proportional. Under
this model, a 55-year-old would subjectively experience time passing 2+1/4
times more quickly than an 11-year-old, rather than 5 times under the
previous. This means the following periods in life would appear to be
quantitatively equal: ages 0–1, 1–4, 4–9, 9–16, 16–25, 25–36, 36–49,
49–64, 64–81, 81–100, 100–121.
In a study, participants consistently provided answers that fit
this model when asked about time perception at 1/4 of their age, but
were less consistent for 1/2 of their age. Their answers suggest that
this model is more accurate than the previous one.
A consequence of this model is that the fraction of subjective
life remaining is always less than the fraction of real life remaining,
but it is always more than one half of real life remaining. This can be seen for and :
Effects of drugs on time perception
Stimulants such as thyroxine, caffeine, and amphetamines lead to overestimation of time intervals by both humans and rats, while depressants and anesthetics such as barbiturates and nitrous oxide can have the opposite effect and lead to underestimation of time intervals. The level of activity in the brain of neurotransmitters such as dopamine and norepinephrine may be the reason for this.
A research on stimulant-dependent individuals (SDI) showed several
abnormal time processing characteristics including larger time
differences for effective duration discrimination, and overestimating
the duration of a relatively long time interval. Altered time processing
and perception in SDI could explain the difficulty SDI have with
delaying gratification.
Another research studied the dose-dependent effect in methamphetamine
dependents with short term abstinence and its effects on time
perception. Results shows that motor timing but not perceptual timing,
was altered in meth dependents, which persisted for at least 3 months of
abstinence. Dose-dependent effects on time perception were only
observed when short-term abstinent meth abusers processed long time
intervals. The study concluded that time perception alteration in meth
dependents is task specific and dose dependent.
The effect of cannabis on time perception
has been studied with inconclusive results mainly due to methodological
variations and the paucity of research. Even though 70% of time
estimation studies report over-estimation, the findings of time
production and time reproduction studies remain inconclusive.
Studies show consistently throughout the literature that most cannabis
users self-report the experience of a slowed perception of time. In the
laboratory, researchers have confirmed the effect of cannabis on the
perception of time in both humans and animals.
Using PET Scans it was observed that participants who showed a decrease
in cerebellar blood flow (CBF) also had a significant alteration in
time sense. The relationship between decreased CBF and impaired time
sense is of interest as the cerebellum is linked to an internal timing
system.
Effects of body temperature
The chemical clock hypothesis implies a causal link between body temperature and the perception of time.
Past work show that increasing body temperature tends to make
individuals experience a dilated perception of time and they perceive
durations as shorter than they actually were, ultimately leading them to
under-estimate time durations. While decreasing body temperature has
the opposite effect – causing participants to experience a condensed
perception of time leading them to over-estimate time duration –
observations of the latter type were rare.
Research establishes a parametric effect of body temperature on time
perception with higher temperatures generally producing faster
subjective time and vice versa. This is especially seen to be true under
changes in arousal levels and stressful events.
Applications
Since
subjective time is measurable, through information such as heartbeats
or actions taken within a time period, there are analytical applications
for time perception.
Social networks
Time perception can be used as a tool in social networks to define the subjective experiences of each node within a system. This method can be used to study characters' psychology in dramas, both film and literature,
analyzed by social networks. Each character's subjective time may be
calculated, with methods as simple as word counting, and compared to the
real time of the story to shed light on their internal states.
Transsaccadic memory
is the neural process that allows humans to perceive their surroundings
as a seamless, unified image despite rapid changes in fixation points.
Transsaccadic memory is a relatively new topic of interest in the field
of psychology. Conflicting views and theories have spurred several types
of experiments intended to explain transsaccadic memory and the neural
mechanisms involved.
In many situations, human eyes move repeatedly in rapid,
discontinuous steps, focusing on a single point for only a short period
of time before moving abruptly to the next point. Rapid eye movements of
this type are called saccades.
If a video camera were to perform such high speed changes in focal
points, the image on screen would be disorienting for a human viewer. In
contrast, despite the rapidly changing sensory input to the visual
system, the normal experience is of a stable visual world; this is an
example of perceptual constancy. Transsaccadic memory is a system that helps maintain this stability despite rapid movement of the eyes.
Theories
Saccade target theory
McConkie's and Currie's saccade target theory is similar to research by Schneider who came up with a similar "reference object theory".
Both theories hypothesize that each saccade is preceded by processes in
the visual system that chose an object as the target for the next
fixation point. The object is usually located in peripheral vision.
The object's features are stored as a mental representation in
transsaccadic memory for identification of future fixations. These
target features are searched for by the visual system when the eye lands
on its fixation point, and the physical features are compared to the
mental representation of the target object. The theory assumes that
visual stability is attained when these processes are successful (when
the visual stimuli and the mental representation of the target object
match). This process occurs before each saccade.
Experiments performed by McConkie to support the role of a saccadic
target in transsaccadic memory show two things: first, there is a
limited peripheral area where a saccadic target exists, and second,
attention is vital in recollection of items in the target area. The
experiments involved recalling changes to an image that occurred in the
peripheral area. Irwin performed similar experiments in which
participants recalled letters that occurred near the target area. Due to confounding
factors of the controlled environment in the studies, the involvement
of saccade target objects is inferred and not established.
Spatiotopic fusion hypothesis
Many
radical views of transsaccadic memory exist. Some are favoured more
than others because of the evidence that supports them. One
less-accepted theory, Breitmeyer's spatiotopic fusion hypothesis,
suggested that successive images are fused based on environmental coordinates
and not retinal ones. In other words, our memory stores a sequence of
images from our surroundings, and joins the images together to give us a
full representation in our brain. The orientation of our retinas
do not have an influence on this form of memory. This theoretical form
of memory supposedly stores highly detailed representations of the world
in a high capacity spatial buffer. Research and experiments by other psychologists provide empirical evidence against these claims.
Dennett
Daniel Dennett
argued that the way we think we are seeing the world is, for the most
part, an illusion. Part of Dennett's argument is the claim that each of
us possess what he calls a "Cartesian theater",
in which we believe there is a full representation of the visual world
in our mind and that there is a place in the mind where it is observed.
According to Dennett, none of this exists. Instead, the only place
where a full and rich representation exists is directly on the fovea, and every time a saccade occurs, the information is overwritten.
Therefore, there is no such thing as transsaccadic memory. Information
previously lost only appears to be retained in visual memory because we
can look again. In this way, the outside world acts as a visual memory.
Since our eyes are constantly moving, we are not aware that visual
inputs are constantly being refreshed to give the illusion of the
completed picture we think we are seeing.
Dennett makes a distinction between the presence of representation, and
the representation of presence. The example he gives regarding this distinction is this: if you were to walk into a room covered in identical portraits of Marilyn Monroe,
you would see that there are many of them, but you would not really be
seeing them all at once. There would be no detailed representation of
each individual portrait just the knowledge that they are present. Dennet's theory raises two relevant questions: 1) How does the visual system detect change in the environment?
2) How much information is retained in each saccade? The proposed
answer to these questions lies in several mechanisms that support a high
sensitivity to change in each visual fixation. These mechanisms are:
retinal adaptation, "pop-out" systems, and motion detectors. The implication of this view is that little information is needed to be retained between each saccade.
Irwin
Irwin's
conclusion regarding transsaccadic memory is that there are no separate
mechanisms, but that rather it is the same as short-term visual memory. Irwin's experiments showed that people cannot fuse pre-saccadic and post-saccadic images in successive fixations. These results are evidence against spatiotopic fusion. According to Irwin, there is no transsaccadic buffer
that holds visual information from one fixation point to the next.
Also, transaccadic memory does not hold detailed spatial information,
but a more abstract representation. Irwin describes transaccadic memory
as an undetailed, limited capacity memory that is relatively
long-lasting.
Many statements have been made concerning the relationship between
transsaccadic memory and visual short-term memory. Researchers have
noted several similar characteristics between the two systems, leading
several to believe that transsaccadic memory is in fact visual
short-term memory or a part of visual short-term memory.
Transsaccadic memory has a limited capacity of three to four items, a
slow decay rate and maskable characteristics. Basically, transsaccadic
memory can hold three to four items for each saccade, and the retention
of items decays or disappears from consciousness slowly after the
presentation of the stimulus. However, once a mask stimulus, such as a
blank screen, is presented immediately after the stimulus, the items
retained prior to the mask can be replaced and/or eliminated faster by
the mask. All of these factors are typical characteristics of visual
short-term memory.
The content stored in transsaccadic memory are less-image like, more
abstract and are sparse representations of the objects, which is found
to be similar to the type of representations in visual short-term
memory.Transsaccadic memory is different from visual short-term memory in that
it takes into account the changes of the target's location due to the
eye moving to new saccades. The information retained between saccades do not take into account positional information very well. Nevertheless, relational and identity information are well retained. Prime and colleagues (2006) hypothesize, transsaccadic memory utilizes egocentric mechanisms, like selective attention,
to reduce the visual search of the target and allow for spatial
information between saccades to be retained and updated by incorporation
of information across saccades.
Transsaccadic memory is characterized by the integration of
information gathered prior to the execution of a saccade (pre-saccadic)
and information gathered after the saccade (post-saccadic stimuli.
This involves attention, locating the targets necessary to perform a
saccade and continuous updates of the environmental information.
Attention occurs prior to the movement of the eyes,
therefore it has a strong influence on the location of the saccade,
what information is being encoded, remembered across saccades and stored
into transsaccadic memory.
In order to perform a successful and accurate saccade an individual is
required to make an attentional shift to the saccadic target. This
attentional shift causes the encoding of information to occur near the
saccade target location.
Attention to the target of the saccade results in better object
identification and an increase in accuracy of identification. As well
as, improvement in coding of locational information.
Attention is restricted to one saccade target per area. It is
impossible to keep attention on a target in one area, while performing
another saccade simultaneously in another. This will cause prolonged
saccadic latency periods (the time it takes to make a saccade from one
area to another), and increased reaction times. However, attention can be distributed around the saccade target, rather than the precise location that will fall on the fovea, allowing for the detection of one or two objects situated around the saccadic target.
Kowler (1995) proposed two models to explain the relationship between
attention, saccades and transsaccadic memory. The spatial model, states
that attention is distributed among the perceptual site (visual field)
and the saccadic target during the latency period, which allows for the
identification of the saccadic target and object surrounding that area.
The temporal model states that attention determines where the saccade
will occur and releases a “go” signal to initiate a saccade within that
area.
Saccadic suppression
is responsible for maintaining a continuous, stable, visual world by
reducing visual sensitivity to events occurring before, during and after
a saccade. The more complex the background on which the stimulus is presented, the larger the suppression. The increase in saccadic suppression can lead to a decrease in detection of change in the visual field. Saccadic suppression can be linked to the phenomenon of change blindness,
in which individuals lack the ability to detect small or large changes
within an environment without the aid of directed attention.
There are two types of saccadic suppression, with the first concerning
the detection of light spot flashes during saccades. The lower the
spatial frequency, meaning fewer objects in the visual field of the
light flashes, the stronger the saccadic suppression. With fewer items
in the visual field it is easier for saccadic suppression to occur. The
higher the spatial frequency, which involves more complex objects within
the visual field, the less likely there will be saccadic suppression.
The second type concerns the detection of image displacement or a
change in an image during eye movement. A displacement between saccades
would not be detected because the movement of the eye eliminates the
signal for the detection of the displacement.
The location of the target forms an image feature that is used by the
visual system to establish space constancy, which maintains the location
of an object in space.
Target blanking is used to study visual stability, space constancy and
the content of information transferred across saccades. Blanking a
target after a saccade eliminates an attempt to make a second saccade,
resulting in the visual system failing to find the target information.
Stability and constancy across the saccades is broken, as a result,
image displacements become easier to detect when blanking occurs during
or right after the saccade.
Neural structures
Superior colliculus
A neural structure located behind the lateral geniculate nucleus that is understood to control eye movements. In particular, the deeper layers of the superior colliculus,
known as lamina VI and VII, have been found to be involved in
initiating and executing saccadic eye movements, which includes the
desired speed and direction of the saccade.
The cells in these layers are organized in a way that forms a map of
the visual field. They are organized according to what direction each
cell moves the eye.
It has been found that activation of specific cells is directed by
where objects in the environment are located in the visual field. Once a
new object is detected, the cells that fire the strongest to stimuli
within this specific area of the visual field will fire, causing the
eyes to move and focus on this object. Although the superior colliculus
may not be directly related to memory for objects across saccades, it is
directly related to the control of saccades and selection of fixation
targets.
V4
This is an area within the visual cortex
that has been found to play an important role in the target selection
of saccades. In other words, this area is important for determining
which objects our eyes shift to when they move. Studies have shown that there is a large amount of activation within the visual area V4 before the saccade even takes place. This occurs in the form of shrinking receptive fields.
The receptive fields of these brain cells tend to shift towards the
object that the eye is about to move towards, generally more so if the
object is close to the original fixation point.
This dynamic change in receptive fields is thought to enhance the
perception and recognition of objects in a visual scene. Because the
receptive fields become smaller around the targeted objects, attention
within the visual scene is very focused on these objects. Increased
attention to target objects within a visual scene help direct eye
movements from one object to another. Understanding of the visual scene
becomes more efficient because these attention shifts guide the eyes
towards relevant objects as opposed to objects that may not be as
important.
Lateral intraparietal cortex
The lateral intraparietal cortex
(LIP) is an area that is believed to be primarily responsible for
keeping an image fluid and undistorted during a saccade (visual/spatial
constancy).
Past work has shown that the LIP stores information of objects before
the saccade (presaccadic), which is then followed by a shift in the
receptive fields of the brain cells of this area to compensate for the
displacement of the retina during a saccade. This shift in the receptive
fields occurs nearly 80 ms before the saccade. The LIP uses
quantitative spatial information in order to achieve this shift, which
allows for the perception of visual and spatial constancy. The
receptive fields of the LIP are quite large and therefore are not well
suited to hold details about the perceived objects in the scene during a
saccade. This is why objects may seem somewhat blurry during eye movements.
Posterior parietal cortex
The posterior parietal cortex (PPC) is a cortical area that is located in front of the parieto-occipital sulcus and is known to play a role in spatial awareness for eye and arm movements. A study using transcranial magnetic stimulation (TMS) found that the PPC also plays an important role in the amount of information held across saccades.
It is believed that transsaccadic memory has the ability to hold
roughly three to four items across each saccade with a fully functional
PPC. When the PPC is temporarily disrupted, especially the PPC of the
right hemisphere, memory across saccades is significantly weakened.
Disruption of the PPC leads to a reduction in the ability to store items
from a span of three or four, to one item. Further research needs to be
conducted in order to fully understand how the PPC is synthesized with
object recognition within transsaccadic memory.
Experiments
Random dot pattern
Irwin's
early experiments tested participants ability to identify random dot
patterns as the same, or as different across saccades. The control
condition for this experiment presented dot patterns in the same spatial
location without saccades, meaning participants had a single fixation
point. A no-overlap control condition presented dot patterns in
different spatial locations, while participants maintained fixation on
one point. This tested the ability of visual short-term memory in
identifying two individual patterns.
The experimental condition showed dot patterns in the same spatial
location but were viewed at separate fixations, forcing the use of
transsaccadic memory. For the experimental condition, participants underwent a calibration
phase, where they were shown five points in separate location to fixate
on individually, for less than two seconds. The next phase presented a
single fixation point for less than two seconds, which was followed by a
random dot pattern presented in a different location, acting as a
saccade target. The dot pattern disappeared when the saccade was
initiated. Another dot pattern then appeared in the same location.
Participants had to identify whether the two patterns were the same or
different.
Results of the experiment showed performance of the experimental
condition to be slightly less accurate than the no-overlap condition.
Irwin attributed this decrease in accuracy to the extra neural processes
involved in performing an eye movement, combined with processing the
dot pattern. He concluded from this that transsaccadic memory does
exist, but that it is very similar if not identical to short term visual
memory and less similar to sensory memory.
Saccade target experiment
The
next step for Irwin was to determine if transsaccadic memory is tied to
spatial position. He performed experiments using dot patterns and
later, performed the same type of experiment alongside McConkie in his
effort to prove the saccade target hypothesis. In those experiments, the
researchers used a picture instead of dot patterns. Participants in the
experimental condition were given an initial eye position, followed by a
saccade target position on the picture. Unlike Irwin's first
experiment, where the pattern did not change spatial location during the
saccade, the picture underwent one of three shift conditions: All shift
down, target object shift down, or background shift up.
Detection of change ended up being much higher when only the target
object moved compared to when the entire image shifted. This
demonstrated the importance of the target object in detection of image
displacements.
Drawing attention to an eccentric target
Kowler
and colleagues were among many to test the relationship between
attention and saccades. In one of their first experiments they
hypothesized that the initiation of saccades required a signal that
would determine which point in space would be the target for the
saccade. They questioned whether the signal was attributed to attention
or if saccades held their own independent filter. If attention was what
decided the location of the target then the saccade latency period would
be longer for saccades made away from the target. Additional time would
be required to shift attention away from the false target to the
correct target. The apparatus was constructed of eight letters arranged
around the perimeter of a circle with a cross fixated at the center.
Three frames were presented at each trial, the first called the pre-mask
held eight letters for 500 ms, the second, labeled critical frame
contained seven characters and a numerical (0-9) saccade target and was
held for 200 ms. The last frame, post-mask, contained all of the
letters. Each trial the identity of the letters, numerical saccade
target and the location of the numerical saccade target were chosen at
random and blind to the participants. Participants focused on the cross
fixation and pressed a button at the start of the trial. After 100 ms a
sequence of the three frames were presented, participants were then
instructed to make a saccade to either the numerical saccade target or
to an opposite character. Once the saccade target was identified
participants pressed a button. Results supported the hypothesis, showing
that directed attention towards the saccade target made the target
easier to identify, decreased latency period and improved on accuracy.
Transsaccadic memory of multiple objects
Prime,
Crawford and Vesia (2008) performed an experiment using a TMS in order
to understand what structure or structures play a role in transsaccadic
memory. It was found that transsaccadic memory was disrupted when TMS
stimulation was delivered to the right posterior parietal cortex (rPPC)
around the time of a saccade. Prime et al. hypothesized that TMS
interfered with the normal spatial remapping operations of the rPPC, in
particular the parietal eye fields, that occur during a saccade.
