Mental chronometry
Encyclopedia
Mental chronometry is the use of response time in perceptual-motor tasks to infer the content, duration, and temporal sequencing of cognitive operations.
Mental chronometry is one of the core paradigms of experimental
and cognitive psychology
, and has found application in various disciplines including cognitive psychophysiology
/cognitive neuroscience
and behavioral neuroscience
to elucidate mechanisms underlying cognitive processing.
Mental chronometry is studied using the measurements of reaction time (RT). Reaction time is the elapsed time between the presentation of a sensory stimulus and the subsequent behavioral response. In psychometric psychology it is considered to be an index of speed of processing. That is, it indicates how fast the thinker can execute the mental operations needed by the task at hand. In turn, speed of processing is considered an index of processing efficiency. The behavioral response is typically a button press but can also be an eye movement, a vocal response, or some other observable behavior.
Usually the focus in research is on reaction time. There are four basic means of measuring RT given different operational conditions during which a subject is to provide a desired response:
Simple reaction time is the time required for an observer to respond to the presence of a stimulus. For example, a subject might be asked to press a button as soon as a light or sound appears. Mean RT for college-age individuals is about 160 millisecond
s to detect an auditory stimulus, and approximately 190 milliseconds to detect visual stimulus. The mean reaction times for sprinters at the Beijing Olympics were 166 ms for males and 189 ms for females, but in one out of 1,000 starts they can achieve 109 ms and 121 ms, respectively Interestingly, that study concluded that longer female reaction times are an artifact of the measurement method used; a suitable lowering of the force threshold on the starting blocks for women would eliminate the sex difference.
Recognition or Go/No-Go reaction time tasks require that the subject press a button when one stimulus type appears and withhold a response when another stimulus type appears. For example, the subject may have to press the button when a green light appears and not respond when a blue light appears.
Choice reaction time (CRT) tasks require distinct responses for each possible class of stimulus. For example, the subject might be asked to press one button if a red light appears and a different button if a yellow light appears. The Jensen Box
is an example of an instrument designed to measure choice reaction time.
Discrimination reaction time involves comparing pairs of simultaneously presented visual displays and then pressing one of two buttons according to which display appears brighter, longer, heavier, or greater in magnitude on some dimension of interest.
Due to momentary attention
al lapses, there is a considerable amount of variability
in an individual's response time, which does not tend to follow a normal (Gaussian) distribution. To control for this, researchers typically require a subject to perform multiple trials, from which a measure of the 'typical' response time can be calculated. Taking the mean of the raw response time is rarely an effective method of characterizing the typical response time, and alternative approaches (such as modeling the entire response time distribution) are often more appropriate.
s have developed and refined mental chronometry for over the past 100 years. The Persian
scientist Abū Rayhān al-Bīrūnī was the first person to describe the concept of reaction time:
is typically credited as the founder of differential psychology, which seeks to determine and explain the mental differences between individuals. He was the first to use rigorous reaction time tests with the express intention of determining averages and ranges of individual differences in mental and behavioral traits in humans. Galton hypothesized that differences in intelligence
would be reflected in variation of sensory discrimination and speed of response to stimuli, and he built various machines to test different measures of this, including reaction time to visual and auditory stimuli. His tests involved a selection of over 10,000 men, women and children from the London public.
(1869). Donders found that simple reaction time is shorter than recognition reaction time, and that choice reaction time is longer than both.
Donders also devised a subtraction method to analyze the time it took for mental operations to take place. By subtracting simple reaction time from choice reaction time, for example, it is possible to calculate how much time is needed to make the connection.
This method provides a way to investigate the cognitive processes underlying simple perceptual-motor tasks, and formed the basis of subsequent developments.
Although Donders' work paved the way for future research in mental chronometry tests, it was not without its drawbacks. Donders' insertion method was based on the assumption that inserting a particular complicating requirement into an RT paradigm would not affect the other components of the test. This assumption - that the incremental effect on RT was strictly additive - was not able to hold up to later experimental tests, which showed that the insertions were able to interact with other portions of the RT paradigm. Despite this, Donders' theories are still of scientific interest and his ideas are still being used in certain areas of psychology, which now have the statistical tools to use them more accurately.
(1952) devised a CRT experiment which presented a series of nine tests in which there are n equally possible choices. The experiment measured the subject's reaction time based on number of possible choices during any given trial. Hick showed that the individual's reaction time increased by a constant amount as a function of available choices, or the "uncertainty" involved in which reaction stimulus would appear next. Uncertainty is measured in "bits", which are defined as the quantity of information that reduces uncertainty by half in information theory
. In Hick's experiment, the reaction time is found to be a function of the binary logarithm
of the number of available choices (n). This phenomenon is called "Hick's Law" and is said to be a measure of the "rate of gain of information." The law is usually expressed by the formula
, where 
and 
are constants representing the intercept and slope of the function, and 
is the number of alternatives. The Jensen Box is a more recent application of Hick's Law. Hick's Law has some interesting modern applications in marketing, where restaurant menus and web interfaces (among other things) take advantage of its principles in striving to achieve speed and ease of use for the consumer.
(1966) devised an experiment wherein subjects were told to remember a set of unique digits in short-term memory
. Subjects were then given a probe stimulus
in the form of a digit from 0-9. The subject then answered as quickly as possible whether the probe was in the previous set of digits or not. The size of the initial set of digits was the independent variable and the reaction time of the subject was the dependent variable. The idea is that as the size of the set of digits increases the number of processes that need to be completed before a decision can be made increases as well. So if the subject has 4 items in short-term memory
(STM), then after encoding the information obtained from the probe stimulus the subject will need to compare the probe to each of the 4 items in memory
and then make a decision. If there were only 2 items in the initial set of digits then the number of processes would be reduced by 2. The data from this study found that for each additional item added to the set of digits that the subject had in STM about 38 milliseconds were added to the response time of the subject. This finding supported the idea that a subject did a serial exhaustive search through memory rather than a serial self-terminating search. Sternberg (1969) developed a much-improved method for dividing reaction time into successive or serial stages, called the additive factor method.
and Metzler (1971) presented a pair of three-dimensional shapes that were identical or mirror-image versions of one another. Reaction time to determine whether they were identical or not was a linear function of the angular difference between their orientation, whether in the picture plane or in depth. They concluded that the observers performed a constant-rate mental rotation to align the two objects so they could be compared. Cooper and Shepard (1973) presented a letter or digit that was either normal or mirror-reversed, and presented either upright or at angles of rotation in units of 60 degrees. The subject had to identify which type of stimulus it was: normal or mirror-reversed. Response time increased roughly linearly as the orientation of the letter deviated from upright (0 degrees) to inverted (180 degrees), and then decreases again until it reaches 360 degrees. The authors concluded that the subjects mentally rotate the image the shortest distance to upright, and then judge whether it is normal or mirror-reversed.
and Quillian (1969) had a hierarchical structure indicating that recall speed in memory should be based on the number of levels in memory traversed in order to find the necessary information. But the experimental results did not agree with this model. For example, a subject will reliably answer that a robin is a bird more quickly than he will answer that an ostrich is a bird despite these questions accessing the same two levels in memory. This led to the development of spreading activation models of memory (e.g., Collins & Loftus, 1975), wherein links in memory are not organized hierarchically but by importance instead.
(1978) used a series of letter-matching studies to measure the mental processing time of several tasks associated with recognition of a pair of letters. The simplest task was the physical match task, in which subjects were shown a pair of letters and had to identify whether the two letters were physically identical or not. The next task was the name match task where subjects had to identify whether two letters had the same name. The task involving the most cognitive processes was the rule match task in which subjects had to determine whether the two letters presented both were vowels or not vowels.
The physical match task was the most simple because mentally subjects had to encode the letters, compare them to each other, and make a decision. When doing the name match task subjects were forced to add a cognitive step before making a decision. They had to search memory for the names of the letters, and then compare those before deciding. In the rule based task they had to also categorize the letters as either vowels or consonants before making their choice. The time taken to perform the rule match task was longer than the name match task which was longer than the physical match task. Using the subtraction method experimenters were able to determine the approximate amount of time that it took for subjects to perform each of the cognitive processes associated with each of these tasks.
. Specifically, various measures of speed of processing were used to examine changes in the speed of information processing as a function of age. Kail (1991) showed that speed of processing increases exponentially from early childhood to early adulthood. Studies of reaction times in young children of various ages are consistent with common observations of children engaged in activities not typically associated with chronometry. This includes speed of counting, reaching for things, repeating words, and other developing vocal and motor skills that develop quickly in growing children. Once reaching early maturity, there is then a long period of stability until speed of processing begins declining from middle age to senility (Salthouse, 2000). In fact, cognitive slowing is considered a good index of broader changes in the functioning of the brain and intelligence
. Demetriou and colleagues, using various methods of measuring speed of processing, showed that it is closely associated with changes in working memory and thought (Demetriou, Mouyi, & Spanoudis, 2009). These relations are extensively discussed in the neo-Piagetian theories of cognitive development
.
During senescence, RT deteriorates (as does fluid intelligence), and this deterioration is systematically associated with changes in many other cognitive processes, such as executive functions, working memory, and inferential processes. In the theory of Andreas Demetriou
, one of the neo-Piagetian theories of cognitive development, change in speed of processing with age, as indicated by decreasing reaction time, is one of the pivotal factors of cognitive development.
s between reaction time and measures of intelligence
: There is thus a tendency for individuals with higher IQ to be faster on reaction time tests.
Research into this link between mental speed and general intelligence
(perhaps first proposed by Charles Spearman
) was re-popularised by Arthur Jensen
, and the "Choice reaction Apparatus
" associated with his name became a common standard tool in reaction time-IQ research.
The strength of the RT-IQ association is a subject of research. Several studies have reported association between simple reaction time and intelligence of around (r=−.31), with a tendency for larger associations between choice reaction time and intelligence (r=−.49). Much of the theoretical interest in reaction time was driven by Hick's Law
, relating the slope of reaction time increases to the complexity of decision required (measured in units of uncertainty popularised by Claude Shannon as the basis of information theory). This promised to link intelligence directly to the resolution of information even in very basic information tasks. There is some support for a link between the slope of the reaction time curve and intelligence, as long as reaction time is tightly controlled.
Standard deviations of reaction times have been found to be more strongly correlated with measures of general intelligence (g) than mean reaction times. The reaction times of low-g individuals are more spread-out than those of high-g individuals.
The cause of the relationship is unclear. It may reflect more efficient information processing, better attentional control, or the integrity of neuronal processes.
With the advent of functional neuroimaging techniques, notably PET
and fMRI, psychologists started to modify their mental chronometry paradigms for functional imaging (Posner, 2005). Although psycho(physio
)logists have been using electroencephalographic
measurements for decades before the conception of PET and fMRI, the images obtained with PET have attracted great interest from other branches of neuroscience, increasingly popularizing mental chronometry among a more elaborate breed of scientists in recent years. The way that mental chronometry is utilized is by performing tasks based on reaction time which measures through neuroimaging the parts of the brain which are involved in the cognitive processes.
In the 1950s, the use of a micro electrode recording of single neurons in anaesthetized monkeys allowed research to look at physiological process in the brain and supported this idea that people encode information serially.
In the 1960s, these methods were used extensively in humans: researchers recorded the electrical potentials in human brain using scalp electrodes while a reaction tasks was being conducted using digital computers. What they found was that there was a connection between the observed electrical potentials with motor and sensory stages for information processing. For example, researchers found in the recorded scalp potentials that the frontal cortex was being activated in association with motor activity. These finding can be connected to Donders’ idea of the subtractive method of the sensory and motor stages involved in reaction tasks.
In the 1970s and early 1980s, development of signal processing
tool for EEG
translated into a revival of research using this technique to assess the timing and the speed of mental processes. For example, high-profile research showed how reaction time on a given trial correlated
with the latency
of the P300
wave or how the timecourse of the EEG reflected the sequence of cognitive processes involved in perceptual processing.
Then, with the invention of functional magnetic resonance imaging
(fMRI), techniques were used to measure activity through electrical event-related potentials in a study when subjects were asked to identify if a digit that was presented was above or below five. According to Sternberg’s additive theory, each of the stages involved in performing this task includes: encoding, comparing against the stored representation for five, selecting a response, and then checking for error in the response. This fMRI image presents the specific locations where these stages are occurring in the brain while performing this simple mental chronometry task.
In the 1980s, neuroimaging experiments allowed researchers to detect the activity in localized brain areas by injecting radionuclides and using positron emission tomography
(PET) to detect them. Also, fMRI was used which have detected the precise brain areas that are active during mental chronometry tasks. Many studies have shown that there is a small number of brain areas which are widely spread out which are involved in performing these cognitive tasks.
Mental chronometry is one of the core paradigms of experimental
Experimental psychology
Experimental psychology is a methodological approach, rather than a subject, and encompasses varied fields within psychology. Experimental psychologists have traditionally conducted research, published articles, and taught classes on neuroscience, developmental psychology, sensation, perception,...
and cognitive psychology
Cognitive psychology
Cognitive psychology is a subdiscipline of psychology exploring internal mental processes.It is the study of how people perceive, remember, think, speak, and solve problems.Cognitive psychology differs from previous psychological approaches in two key ways....
, and has found application in various disciplines including cognitive psychophysiology
Physiological psychology
Physiological psychology is a subdivision of behavioral neuroscience that studies the neural mechanisms of perception and behavior through direct manipulation of the brains of nonhuman animal subjects in controlled experiments...
/cognitive neuroscience
Cognitive neuroscience
Cognitive neuroscience is an academic field concerned with the scientific study of biological substrates underlying cognition, with a specific focus on the neural substrates of mental processes. It addresses the questions of how psychological/cognitive functions are produced by the brain...
and behavioral neuroscience
Behavioral neuroscience
Behavioral neuroscience, also known as biological psychology, biopsychology, or psychobiology is the application of the principles of biology , to the study of physiological, genetic, and developmental mechanisms of behavior in human and non-human animals...
to elucidate mechanisms underlying cognitive processing.
Mental chronometry is studied using the measurements of reaction time (RT). Reaction time is the elapsed time between the presentation of a sensory stimulus and the subsequent behavioral response. In psychometric psychology it is considered to be an index of speed of processing. That is, it indicates how fast the thinker can execute the mental operations needed by the task at hand. In turn, speed of processing is considered an index of processing efficiency. The behavioral response is typically a button press but can also be an eye movement, a vocal response, or some other observable behavior.
Types
Response time is the sum of reaction time plus movement time.Usually the focus in research is on reaction time. There are four basic means of measuring RT given different operational conditions during which a subject is to provide a desired response:
Simple reaction time is the time required for an observer to respond to the presence of a stimulus. For example, a subject might be asked to press a button as soon as a light or sound appears. Mean RT for college-age individuals is about 160 millisecond
Millisecond
A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....
s to detect an auditory stimulus, and approximately 190 milliseconds to detect visual stimulus. The mean reaction times for sprinters at the Beijing Olympics were 166 ms for males and 189 ms for females, but in one out of 1,000 starts they can achieve 109 ms and 121 ms, respectively Interestingly, that study concluded that longer female reaction times are an artifact of the measurement method used; a suitable lowering of the force threshold on the starting blocks for women would eliminate the sex difference.
Recognition or Go/No-Go reaction time tasks require that the subject press a button when one stimulus type appears and withhold a response when another stimulus type appears. For example, the subject may have to press the button when a green light appears and not respond when a blue light appears.
Choice reaction time (CRT) tasks require distinct responses for each possible class of stimulus. For example, the subject might be asked to press one button if a red light appears and a different button if a yellow light appears. The Jensen Box
Jensen Box
The Jensen Box was developed by University of California, Berkeley psychologist Arthur Jensen as a standard apparatus for measuring choice reaction time, especially in relationship to differences in intelligence....
is an example of an instrument designed to measure choice reaction time.
Discrimination reaction time involves comparing pairs of simultaneously presented visual displays and then pressing one of two buttons according to which display appears brighter, longer, heavier, or greater in magnitude on some dimension of interest.
Due to momentary attention
Attention
Attention is the cognitive process of paying attention to one aspect of the environment while ignoring others. Attention is one of the most intensely studied topics within psychology and cognitive neuroscience....
al lapses, there is a considerable amount of variability
Statistical dispersion
In statistics, statistical dispersion is variability or spread in a variable or a probability distribution...
in an individual's response time, which does not tend to follow a normal (Gaussian) distribution. To control for this, researchers typically require a subject to perform multiple trials, from which a measure of the 'typical' response time can be calculated. Taking the mean of the raw response time is rarely an effective method of characterizing the typical response time, and alternative approaches (such as modeling the entire response time distribution) are often more appropriate.
Abū Rayhān al-Bīrūnī
PsychologistPsychologist
Psychologist is a professional or academic title used by individuals who are either:* Clinical professionals who work with patients in a variety of therapeutic contexts .* Scientists conducting psychological research or teaching psychology in a college...
s have developed and refined mental chronometry for over the past 100 years. The Persian
Persian people
The Persian people are part of the Iranian peoples who speak the modern Persian language and closely akin Iranian dialects and languages. The origin of the ethnic Iranian/Persian peoples are traced to the Ancient Iranian peoples, who were part of the ancient Indo-Iranians and themselves part of...
scientist Abū Rayhān al-Bīrūnī was the first person to describe the concept of reaction time:
Galton and differential psychology
Sir Francis GaltonFrancis Galton
Sir Francis Galton /ˈfrɑːnsɪs ˈgɔːltn̩/ FRS , cousin of Douglas Strutt Galton, half-cousin of Charles Darwin, was an English Victorian polymath: anthropologist, eugenicist, tropical explorer, geographer, inventor, meteorologist, proto-geneticist, psychometrician, and statistician...
is typically credited as the founder of differential psychology, which seeks to determine and explain the mental differences between individuals. He was the first to use rigorous reaction time tests with the express intention of determining averages and ranges of individual differences in mental and behavioral traits in humans. Galton hypothesized that differences in intelligence
Intelligence
Intelligence has been defined in different ways, including the abilities for abstract thought, understanding, communication, reasoning, learning, planning, emotional intelligence and problem solving....
would be reflected in variation of sensory discrimination and speed of response to stimuli, and he built various machines to test different measures of this, including reaction time to visual and auditory stimuli. His tests involved a selection of over 10,000 men, women and children from the London public.
Donders' experiment
The first scientist to measure reaction time in the laboratory was Franciscus DondersFranciscus Donders
-External links:* B. Theunissen. , F.C. Donders: turning refracting into science, @ History of science and scholarship in the Netherlands.* in the Virtual Laboratory of the Max Planck Institute for the History of Science* P. Eling, , Geneeskundige en fysioloog....
(1869). Donders found that simple reaction time is shorter than recognition reaction time, and that choice reaction time is longer than both.
This method provides a way to investigate the cognitive processes underlying simple perceptual-motor tasks, and formed the basis of subsequent developments.
Although Donders' work paved the way for future research in mental chronometry tests, it was not without its drawbacks. Donders' insertion method was based on the assumption that inserting a particular complicating requirement into an RT paradigm would not affect the other components of the test. This assumption - that the incremental effect on RT was strictly additive - was not able to hold up to later experimental tests, which showed that the insertions were able to interact with other portions of the RT paradigm. Despite this, Donders' theories are still of scientific interest and his ideas are still being used in certain areas of psychology, which now have the statistical tools to use them more accurately.
Hick's Law
W. E. HickW. E. Hick
William Edmund Hick was a British psychologist, who was a pioneer in the new sciences of experimental psychology and ergonomics in the mid-20th century....
(1952) devised a CRT experiment which presented a series of nine tests in which there are n equally possible choices. The experiment measured the subject's reaction time based on number of possible choices during any given trial. Hick showed that the individual's reaction time increased by a constant amount as a function of available choices, or the "uncertainty" involved in which reaction stimulus would appear next. Uncertainty is measured in "bits", which are defined as the quantity of information that reduces uncertainty by half in information theory
Information theory
Information theory is a branch of applied mathematics and electrical engineering involving the quantification of information. Information theory was developed by Claude E. Shannon to find fundamental limits on signal processing operations such as compressing data and on reliably storing and...
. In Hick's experiment, the reaction time is found to be a function of the binary logarithm
Binary logarithm
In mathematics, the binary logarithm is the logarithm to the base 2. It is the inverse function of n ↦ 2n. The binary logarithm of n is the power to which the number 2 must be raised to obtain the value n. This makes the binary logarithm useful for anything involving powers of 2,...
of the number of available choices (n). This phenomenon is called "Hick's Law" and is said to be a measure of the "rate of gain of information." The law is usually expressed by the formula
, where and are constants representing the intercept and slope of the function, and is the number of alternatives. The Jensen Box is a more recent application of Hick's Law. Hick's Law has some interesting modern applications in marketing, where restaurant menus and web interfaces (among other things) take advantage of its principles in striving to achieve speed and ease of use for the consumer.Sternberg’s memory-scanning task
SternbergSaul Sternberg
Saul Sternberg is a Professor Emeritus of Psychology and former Paul C. Williams Term Professor at the University of Pennsylvania. He is a pioneer in the field of cognitive psychology in the development of experimental techniques to study human information processing...
(1966) devised an experiment wherein subjects were told to remember a set of unique digits in short-term memory
Short-term memory
Short-term memory is the capacity for holding a small amount of information in mind in an active, readily available state for a short period of time. The duration of short-term memory is believed to be in the order of seconds. A commonly cited capacity is 7 ± 2 elements...
. Subjects were then given a probe stimulus
Stimulation
Stimulation is the action of various agents on nerves, muscles, or a sensory end organ, by which activity is evoked; especially, the nervous impulse produced by various agents on nerves, or a sensory end organ, by which the part connected with the nerve is thrown into a state of activity.The word...
in the form of a digit from 0-9. The subject then answered as quickly as possible whether the probe was in the previous set of digits or not. The size of the initial set of digits was the independent variable and the reaction time of the subject was the dependent variable. The idea is that as the size of the set of digits increases the number of processes that need to be completed before a decision can be made increases as well. So if the subject has 4 items in short-term memory
Short-term memory
Short-term memory is the capacity for holding a small amount of information in mind in an active, readily available state for a short period of time. The duration of short-term memory is believed to be in the order of seconds. A commonly cited capacity is 7 ± 2 elements...
(STM), then after encoding the information obtained from the probe stimulus the subject will need to compare the probe to each of the 4 items in memory
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
and then make a decision. If there were only 2 items in the initial set of digits then the number of processes would be reduced by 2. The data from this study found that for each additional item added to the set of digits that the subject had in STM about 38 milliseconds were added to the response time of the subject. This finding supported the idea that a subject did a serial exhaustive search through memory rather than a serial self-terminating search. Sternberg (1969) developed a much-improved method for dividing reaction time into successive or serial stages, called the additive factor method.
Shepard and Metzler’s mental rotation task
ShepardRoger Shepard
Roger Newland Shepard is a cognitive scientist and author of Toward a Universal Law of Generalization for Psychological Science. He is seen as a father of research on spatial relations....
and Metzler (1971) presented a pair of three-dimensional shapes that were identical or mirror-image versions of one another. Reaction time to determine whether they were identical or not was a linear function of the angular difference between their orientation, whether in the picture plane or in depth. They concluded that the observers performed a constant-rate mental rotation to align the two objects so they could be compared. Cooper and Shepard (1973) presented a letter or digit that was either normal or mirror-reversed, and presented either upright or at angles of rotation in units of 60 degrees. The subject had to identify which type of stimulus it was: normal or mirror-reversed. Response time increased roughly linearly as the orientation of the letter deviated from upright (0 degrees) to inverted (180 degrees), and then decreases again until it reaches 360 degrees. The authors concluded that the subjects mentally rotate the image the shortest distance to upright, and then judge whether it is normal or mirror-reversed.
Sentence-picture verification
Mental chronometry has been a useful tool in identifying some of the processes associated with understanding a sentence. This type of research typically revolves around the differences in processing 4 types of sentences: true affirmative (TA), false affirmative (FA), false negative (FN), and true negative (TN). A picture can be presented with an associated sentence that falls into one of these 4 categories. The subject then decides if the sentence matches the picture or does not. The type of sentence determines how many processes need to be performed before a decision can be made. According to the data from Clark and Chase (1972) and Just and Carpenter (1971), the TA sentences are the simplest and take the least time, than FA, FN, and TN sentences.Mental chronometry and models of memory
Hierarchical network models of memory were largely discarded due to some findings related to mental chronometry. The TLC model proposed by CollinsAllan M. Collins
Allan M. Collins is an American cognitive scientist and Professor Emeritus of Learning Sciences at Northwestern University's School of Education and Social Policy...
and Quillian (1969) had a hierarchical structure indicating that recall speed in memory should be based on the number of levels in memory traversed in order to find the necessary information. But the experimental results did not agree with this model. For example, a subject will reliably answer that a robin is a bird more quickly than he will answer that an ostrich is a bird despite these questions accessing the same two levels in memory. This led to the development of spreading activation models of memory (e.g., Collins & Loftus, 1975), wherein links in memory are not organized hierarchically but by importance instead.
Posner’s letter matching studies
PosnerMichael Posner (psychologist)
Michael I. Posner is the editor of numerous cognitive and neuroscience compilations and is an eminent researcher in the field of attention...
(1978) used a series of letter-matching studies to measure the mental processing time of several tasks associated with recognition of a pair of letters. The simplest task was the physical match task, in which subjects were shown a pair of letters and had to identify whether the two letters were physically identical or not. The next task was the name match task where subjects had to identify whether two letters had the same name. The task involving the most cognitive processes was the rule match task in which subjects had to determine whether the two letters presented both were vowels or not vowels.
The physical match task was the most simple because mentally subjects had to encode the letters, compare them to each other, and make a decision. When doing the name match task subjects were forced to add a cognitive step before making a decision. They had to search memory for the names of the letters, and then compare those before deciding. In the rule based task they had to also categorize the letters as either vowels or consonants before making their choice. The time taken to perform the rule match task was longer than the name match task which was longer than the physical match task. Using the subtraction method experimenters were able to determine the approximate amount of time that it took for subjects to perform each of the cognitive processes associated with each of these tasks.
Mental chronometry and cognitive development
In recent years there has been extensive research using mental chronometry methods for the study of cognitive developmentCognitive development
Cognitive development is a field of study in neuroscience and psychology focusing on a child's development in terms of information processing, conceptual resources, perceptual skill, language learning, and other aspects of brain development and cognitive psychology compared to an adult's point of...
. Specifically, various measures of speed of processing were used to examine changes in the speed of information processing as a function of age. Kail (1991) showed that speed of processing increases exponentially from early childhood to early adulthood. Studies of reaction times in young children of various ages are consistent with common observations of children engaged in activities not typically associated with chronometry. This includes speed of counting, reaching for things, repeating words, and other developing vocal and motor skills that develop quickly in growing children. Once reaching early maturity, there is then a long period of stability until speed of processing begins declining from middle age to senility (Salthouse, 2000). In fact, cognitive slowing is considered a good index of broader changes in the functioning of the brain and intelligence
Intelligence
Intelligence has been defined in different ways, including the abilities for abstract thought, understanding, communication, reasoning, learning, planning, emotional intelligence and problem solving....
. Demetriou and colleagues, using various methods of measuring speed of processing, showed that it is closely associated with changes in working memory and thought (Demetriou, Mouyi, & Spanoudis, 2009). These relations are extensively discussed in the neo-Piagetian theories of cognitive development
Neo-Piagetian theories of cognitive development
Jean Piaget's theory of cognitive development has been criticized on many grounds. One criticism is concerned with the very nature of development itself. It is suggested that Piaget's theory does not explain why development from stage to stage occurs. The theory is also criticized for ignoring...
.
During senescence, RT deteriorates (as does fluid intelligence), and this deterioration is systematically associated with changes in many other cognitive processes, such as executive functions, working memory, and inferential processes. In the theory of Andreas Demetriou
Andreas Demetriou
Andreas Demetriou is a well known Greek Cypriot developmental psychologist and a former Minister of Education and Culture of Cyprus.- Life :...
, one of the neo-Piagetian theories of cognitive development, change in speed of processing with age, as indicated by decreasing reaction time, is one of the pivotal factors of cognitive development.
Mental chronometry and cognitive ability
Researchers have reported medium-sized correlationCorrelation
In statistics, dependence refers to any statistical relationship between two random variables or two sets of data. Correlation refers to any of a broad class of statistical relationships involving dependence....
s between reaction time and measures of intelligence
Intelligence
Intelligence has been defined in different ways, including the abilities for abstract thought, understanding, communication, reasoning, learning, planning, emotional intelligence and problem solving....
: There is thus a tendency for individuals with higher IQ to be faster on reaction time tests.
Research into this link between mental speed and general intelligence
General intelligence factor
The g factor, where g stands for general intelligence, is a statistic used in psychometrics to model the mental ability underlying results of various tests of cognitive ability...
(perhaps first proposed by Charles Spearman
Charles Spearman
Charles Edward Spearman, FRS was an English psychologist known for work in statistics, as a pioneer of factor analysis, and for Spearman's rank correlation coefficient...
) was re-popularised by Arthur Jensen
Arthur Jensen
Arthur Robert Jensen is a Professor Emeritus of educational psychology at the University of California, Berkeley. Jensen is known for his work in psychometrics and differential psychology, which is concerned with how and why individuals differ behaviorally from one another.He is a major proponent...
, and the "Choice reaction Apparatus
Jensen Box
The Jensen Box was developed by University of California, Berkeley psychologist Arthur Jensen as a standard apparatus for measuring choice reaction time, especially in relationship to differences in intelligence....
" associated with his name became a common standard tool in reaction time-IQ research.
The strength of the RT-IQ association is a subject of research. Several studies have reported association between simple reaction time and intelligence of around (r=−.31), with a tendency for larger associations between choice reaction time and intelligence (r=−.49). Much of the theoretical interest in reaction time was driven by Hick's Law
Hick's law
Hick's Law, named after British psychologist William Edmund Hick, or the Hick–Hyman Law , describes the time it takes for a person to make a decision as a result of the possible choices he or she has. The Hick-Hyman Law assesses cognitive information capacity in choice reaction experiments...
, relating the slope of reaction time increases to the complexity of decision required (measured in units of uncertainty popularised by Claude Shannon as the basis of information theory). This promised to link intelligence directly to the resolution of information even in very basic information tasks. There is some support for a link between the slope of the reaction time curve and intelligence, as long as reaction time is tightly controlled.
Standard deviations of reaction times have been found to be more strongly correlated with measures of general intelligence (g) than mean reaction times. The reaction times of low-g individuals are more spread-out than those of high-g individuals.
The cause of the relationship is unclear. It may reflect more efficient information processing, better attentional control, or the integrity of neuronal processes.
Application of mental chronometry in biological psychology/cognitive neuroscience
Positron emission tomography
Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
and fMRI, psychologists started to modify their mental chronometry paradigms for functional imaging (Posner, 2005). Although psycho(physio
Physiological psychology
Physiological psychology is a subdivision of behavioral neuroscience that studies the neural mechanisms of perception and behavior through direct manipulation of the brains of nonhuman animal subjects in controlled experiments...
)logists have been using electroencephalographic
Electroencephalography
Electroencephalography is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain...
measurements for decades before the conception of PET and fMRI, the images obtained with PET have attracted great interest from other branches of neuroscience, increasingly popularizing mental chronometry among a more elaborate breed of scientists in recent years. The way that mental chronometry is utilized is by performing tasks based on reaction time which measures through neuroimaging the parts of the brain which are involved in the cognitive processes.
In the 1950s, the use of a micro electrode recording of single neurons in anaesthetized monkeys allowed research to look at physiological process in the brain and supported this idea that people encode information serially.
In the 1960s, these methods were used extensively in humans: researchers recorded the electrical potentials in human brain using scalp electrodes while a reaction tasks was being conducted using digital computers. What they found was that there was a connection between the observed electrical potentials with motor and sensory stages for information processing. For example, researchers found in the recorded scalp potentials that the frontal cortex was being activated in association with motor activity. These finding can be connected to Donders’ idea of the subtractive method of the sensory and motor stages involved in reaction tasks.
In the 1970s and early 1980s, development of signal processing
Signal processing
Signal processing is an area of systems engineering, electrical engineering and applied mathematics that deals with operations on or analysis of signals, in either discrete or continuous time...
tool for EEG
EEG
EEG commonly refers to electroencephalography, a measurement of the electrical activity of the brain.EEG may also refer to:* Emperor Entertainment Group, a Hong Kong-based entertainment company...
translated into a revival of research using this technique to assess the timing and the speed of mental processes. For example, high-profile research showed how reaction time on a given trial correlated
Correlation
In statistics, dependence refers to any statistical relationship between two random variables or two sets of data. Correlation refers to any of a broad class of statistical relationships involving dependence....
with the latency
Latency
Latency or latent may refer to:*Latency period , the time between exposure to a pathogen, chemical or radiation, and when symptoms first become apparent...
of the P300
P300
The P300 wave is an event related potential elicited by infrequent, task-relevant stimuli. It is considered to be an endogenous potential as its occurrence links not to the physical attributes of a stimulus but to a person's reaction to the stimulus. More specifically, the P300 is thought to...
wave or how the timecourse of the EEG reflected the sequence of cognitive processes involved in perceptual processing.
Then, with the invention of functional magnetic resonance imaging
Functional magnetic resonance imaging
Functional magnetic resonance imaging or functional MRI is a type of specialized MRI scan used to measure the hemodynamic response related to neural activity in the brain or spinal cord of humans or other animals. It is one of the most recently developed forms of neuroimaging...
(fMRI), techniques were used to measure activity through electrical event-related potentials in a study when subjects were asked to identify if a digit that was presented was above or below five. According to Sternberg’s additive theory, each of the stages involved in performing this task includes: encoding, comparing against the stored representation for five, selecting a response, and then checking for error in the response. This fMRI image presents the specific locations where these stages are occurring in the brain while performing this simple mental chronometry task.
In the 1980s, neuroimaging experiments allowed researchers to detect the activity in localized brain areas by injecting radionuclides and using positron emission tomography
Positron emission tomography
Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
(PET) to detect them. Also, fMRI was used which have detected the precise brain areas that are active during mental chronometry tasks. Many studies have shown that there is a small number of brain areas which are widely spread out which are involved in performing these cognitive tasks.
See also
- Jensen BoxJensen BoxThe Jensen Box was developed by University of California, Berkeley psychologist Arthur Jensen as a standard apparatus for measuring choice reaction time, especially in relationship to differences in intelligence....
- CDR Computerized Assessment SystemCDR Computerized Assessment SystemThe CDR Computerized Assessment System is a computerized battery of cognitive tests designed in the late 1970s by Professor Keith Wesnes at the University of Reading in Berkshire, England, for repeated testing in clinical trails...
- Implicit Association TestImplicit Association TestThe Implicit Association Test is a measure within social psychology designed to detect the strength of a person's automatic association between mental representations of objects in memory. The IAT was introduced in the scientific literature in 1998 by Anthony Greenwald, Debbie McGee, and Jordan...
- Inspection timeInspection timeInspection time refers to the exposure duration required for a human subject to reliably identify a simple stimulus. Typically a stimulus made up of two parallel lines differing in length and joined at the tops by a cross bar is presented...
External links
- Reaction Time Test - Measuring Mental Chronometry on the Web
- Historical Introduction to Cognitive Psychology
- Timing the Brain: Mental Chronometry as a Tool in Neuroscience
- Sample Chronometric Test on the web