biology

Psychological refractory period

Psychological refractory period is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Psychological refractory period rather than just read about it. In short: 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 is of both practical and theoretical importance.

Key takeaways

Psychological refractory period belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Psychological refractory period to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Psychological refractory period from memory before moving on to harder problems.

Reference excerpt

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 is of both practical and theoretical importance. The PRP can be used to investigate many questions about divided attention, examining tasks 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.

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 variable 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 a wide variety of different topics in psychology.

Personality 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 decrease 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 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 language 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.

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 driving. Hal Pashler and his colleagues tested subjects 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, they took longer to brake, which could potentially translate into a longer distance needed to slow driving or potential collisions.

Alcohol and caffeine Alcohol 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.

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, through task automatization. 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.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Psychological refractory period

Start with the simplest possible case. Write down what Psychological refractory period claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Psychological refractory period before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Psychological refractory period ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Psychological refractory period

In research: Psychological refractory period appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Psychological refractory period in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Psychological refractory period is common in secondary-school and first-year university syllabi. It links to neighbouring topics Neuropsychology, so understanding it makes those chapters shorter.
In everyday life: Look for Psychological refractory period outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Psychological refractory period in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Psychological refractory period means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Psychological refractory period out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Psychological refractory period in simple terms?

Why does Psychological refractory period matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Psychological refractory period?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Psychological refractory period.