Psychological refractory period
Encyclopedia
The term psychological refractory period (PRP) refers to the period of time during which the response to a second stimulus is significantly slowed because a first stimulus is still being processed. This delay in response time when one is required to divide attention can exhibit a negative effect that is evident in many fields of study. The PRP can be used to investigate many areas of research that study processes which require divided attention, such as reading aloud, language, or driving and talking on the phone. PRP effects related to personality
, age
, and level of alcohol
or caffeine
intake have also been investigated.
in this paradigm, and the reaction time to the second stimulus acts as the dependent variable.
An example of a PRP paradigm might be that there is a task 1 which requires participants to push the keyboard-letter ‘n’ with the right index finger when a square frame was green. There is also a task 2 which requires participants to push the keyboard-letter ‘v’ with the left index finger when the digit displayed was a ‘3’ and to push the letter ‘c’ with the left middle finger if the digit displayed was a ‘4’. If the temporal distance between the two tasks is varied, for example 150 ms in one and 1000ms in another, the time to respond to the second task will be longer when the interval occurring between the two tasks is 150 ms than when it is 1000 ms. Referring to figure 1, the SLACK intervening between the execution of the first and second task will be absorbed when the interval intervening between the two tasks is long rather than when it is short.
areas other than reading aloud are affected by PRP. Grammar
whether it be open words such as nouns, or closed words such as determiners, pronoun, prepositions, conjunctions etc. require central attention.
. Participants took part in a driving simulation, and as they drove they would occasionally hear a tone
. Once they heard the tone, they had to call out the number of the tone. The car in front of them would occasionally brake
, causing the participant to brake. The results indicated that when they had to respond to a tone, the took longer to brake, which could potentially translate into a longer distance needed to slow driving or potential collisions.
impairs both speed
and accuracy performance in PRP tasks, and while caffeine
can reduce speed impairments, accuracy remains poor. Participants in this study performed a PRP task that measured dual-task interference. Performance was tested under 2 active doses and 1 placebo
dose of caffeine in combination with 1 active dose and 1 placebo dose of alcohol. Results indicated that alcohol impaired PRP performance for both speed and accuracy, and the combination of caffeine and alcohol impaired PRP performance for accuracy but not speed. Therefore although caffeine may counterbalance alcohol in terms of reaction time, it fails to counterbalance in terms of accuracy.
These differences could be due to the fact that older adults have a reduced ability to bypass the central bottleneck
, through task atomization. Older and younger participants first learned to perform an auditory vocal task. They then participated in a PRP paradigm, with a manual response to a visual stimulus, followed by a highly practiced auditory vocal task. Results indicated that there was a processing bottleneck in all but 1 of the older adults. Therefore, older adults either have the ability to use automatic-memory retrieval and bypass the bottleneck and it is just less likely to be used, or they have actual lost the ability entirely.
regions in both the back and front of the brain are activated. These areas are notable for processing visual information as well as cognitive and motor information respectfully. This PRP effect is most likely to be evident when an in individual is stressed or is experiencing exhaustion. The PRP is likely caused by a combination of two approaches; the bottleneck
approach and the capacity
approach. These concepts vary in specific mechanisms, however, they both propose an overall limit to the amount of mental activity in which we can engage in.
Personality
Personality is the particular combination of emotional, attitudinal, and behavioral response patterns of an individual.-Psychology:* Personality development, the concept that personality is affected by various sources* Personality disorder...
, age
Age
Age may refer to:* Age , an aspect of mathematical model theory* Age , an international peer-reviewed journal operated by Springer.* The Age, a daily newspaper published in Melbourne, Australia* Agé, a god* Åge, a given name...
, and level of alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
or caffeine
Caffeine
Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...
intake have also been investigated.
Methods
PRP is a product of the psychological refractory period paradigm, a paradigm in which two different stimuli are presented in rapid succession, each requiring a fast response. Stimulus onset asynchrony, the time that lapses between the presentations of the two stimuli, acts as the independent variableIndependent variable
The terms "dependent variable" and "independent variable" are used in similar but subtly different ways in mathematics and statistics as part of the standard terminology in those subjects...
in this paradigm, and the reaction time to the second stimulus acts as the dependent variable.
An example of a PRP paradigm might be that there is a task 1 which requires participants to push the keyboard-letter ‘n’ with the right index finger when a square frame was green. There is also a task 2 which requires participants to push the keyboard-letter ‘v’ with the left index finger when the digit displayed was a ‘3’ and to push the letter ‘c’ with the left middle finger if the digit displayed was a ‘4’. If the temporal distance between the two tasks is varied, for example 150 ms in one and 1000ms in another, the time to respond to the second task will be longer when the interval occurring between the two tasks is 150 ms than when it is 1000 ms. Referring to figure 1, the SLACK intervening between the execution of the first and second task will be absorbed when the interval intervening between the two tasks is long rather than when it is short.
Results
Researchers have used the PRP paradigm design to study various topics in psychology, and various results indicate how these areas of psychology are negatively affected by the psychological refractory period delay.Personality and Intelligence
PRP is not dependent on personality . Upon experimentation, participants were tested with a PRP paradigm in which the first task was an auditory task and the second task was a visual two choice task. Results indicated that there is an overall decreased in reaction time, exhibiting a psychological refractory period effect, however, there was no effect due to varying levels of extroversion and introversion.Language
PRP studies have challenged the notion of that central attention does not play a role in reading aloud . Upon experimentation, participants were primed with exception words (pin, mint, hint, lint) and pseudohomophones (brain and brane). In the PRP paradigm they were first asked to read the words aloud quickly, and then asked to respond to a tone by responding to the letter string (counterbalance order of words). Results indicated that the phonological process of reading aloud is not automatic it utilizes central attention, because reading aloud also exhibits a PRP effect. It was also determined that other languageLanguage
Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...
areas other than reading aloud are affected by PRP. Grammar
Grammar
In linguistics, grammar is the set of structural rules that govern the composition of clauses, phrases, and words in any given natural language. The term refers also to the study of such rules, and this field includes morphology, syntax, and phonology, often complemented by phonetics, semantics,...
whether it be open words such as nouns, or closed words such as determiners, pronoun, prepositions, conjunctions etc. require central attention.
Driving
The PRP affects not only simple dual tasks such as the way we read or speak, it also can affect more complicated tasks such as drivingDriving
Driving is the controlled operation and movement of a land vehicle, such as a car, truck or bus.Although direct operation of a bicycle and a mounted animal are commonly referred to as riding, such operators are legally considered drivers and are required to obey the rules of the road...
. Participants took part in a driving simulation, and as they drove they would occasionally hear a tone
Tone
- Tone :* Tone , a literary technique which encompasses the attitudes toward the subject and toward the audience implied in a literary work* Tone , the pitch and pitch changes in words of certain languages...
. Once they heard the tone, they had to call out the number of the tone. The car in front of them would occasionally brake
Brake
A brake is a mechanical device which inhibits motion. Its opposite component is a clutch. The rest of this article is dedicated to various types of vehicular brakes....
, causing the participant to brake. The results indicated that when they had to respond to a tone, the took longer to brake, which could potentially translate into a longer distance needed to slow driving or potential collisions.
Alcohol and Caffeine
AlcoholAlcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
impairs both speed
Speed
In kinematics, the speed of an object is the magnitude of its velocity ; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as...
and accuracy performance in PRP tasks, and while caffeine
Caffeine
Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...
can reduce speed impairments, accuracy remains poor. Participants in this study performed a PRP task that measured dual-task interference. Performance was tested under 2 active doses and 1 placebo
Placebo
A placebo is a simulated or otherwise medically ineffectual treatment for a disease or other medical condition intended to deceive the recipient...
dose of caffeine in combination with 1 active dose and 1 placebo dose of alcohol. Results indicated that alcohol impaired PRP performance for both speed and accuracy, and the combination of caffeine and alcohol impaired PRP performance for accuracy but not speed. Therefore although caffeine may counterbalance alcohol in terms of reaction time, it fails to counterbalance in terms of accuracy.
Aging
PRP becomes more apparent as we age. However, studies have aimed to determine if dual-task practice can help remove elderly disadvantages. It was previously determined from experimentation with young adults that practice reduces reaction time in both simple and PRP conditions; however, after consecutive days the PRP effect was still found to be evident, and therefore was still a function of stimulus onset asynchrony. However, this finding was further tested with older adults. Young and old participants were assigned to practice 7 blocks of PRP paradigm design. The first task required a vocal response to an auditory stimulus, followed by a manual response to a visual stimulus second task. Results showed that practice did not reduce PRP differences between the old and young. They administered the experiment again with either a less complicated first task or less complicated second task. Results showed that previous practice helped reduce PRP only for older adults. Therefore, older adults have a difficult time switching from task 1 to task 2 that is most profound when either the first or second task is difficult.These differences could be due to the fact that older adults have a reduced ability to bypass the central bottleneck
Bottleneck
A bottleneck is a phenomenon where the performance or capacity of an entire system is limited by a single or limited number of components or resources. The term bottleneck is taken from the 'assets are water' metaphor. As water is poured out of a bottle, the rate of outflow is limited by the width...
, through task atomization. Older and younger participants first learned to perform an auditory vocal task. They then participated in a PRP paradigm, with a manual response to a visual stimulus, followed by a highly practiced auditory vocal task. Results indicated that there was a processing bottleneck in all but 1 of the older adults. Therefore, older adults either have the ability to use automatic-memory retrieval and bypass the bottleneck and it is just less likely to be used, or they have actual lost the ability entirely.
Theories
During the psychological refractory period, a network of brainBrain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
regions in both the back and front of the brain are activated. These areas are notable for processing visual information as well as cognitive and motor information respectfully. This PRP effect is most likely to be evident when an in individual is stressed or is experiencing exhaustion. The PRP is likely caused by a combination of two approaches; the bottleneck
Bottleneck
A bottleneck is a phenomenon where the performance or capacity of an entire system is limited by a single or limited number of components or resources. The term bottleneck is taken from the 'assets are water' metaphor. As water is poured out of a bottle, the rate of outflow is limited by the width...
approach and the capacity
Capacity
Capacity is the ability to hold a fluid, very similar to volume.Capacity may also refer to:* Capacity utilization, in economics, the extent to which an enterprise or a nation actually uses its potential output...
approach. These concepts vary in specific mechanisms, however, they both propose an overall limit to the amount of mental activity in which we can engage in.