Psychological Refractory Period (PRP)
Dual-task paradigm showing delayed RT2 at short SOA due to central bottleneck.
Show Details
Dual-task paradigm showing delayed RT2 at short SOA due to central bottleneck.
In the PRP paradigm, two stimuli are presented in close succession. Participants respond to each stimulus in order.
When the Stimulus Onset Asynchrony (SOA) is short, the second response (RT2) is delayed due to a central processing bottleneck.
This implementation measures RT1 and RT2 across multiple SOAs and reports accuracy and timing effects.
Design Highlights
- Two sequential tasks: tone classification (low/high) followed by color classification (yellow/blue).
- SOA values varied (50/150/300/800 ms) to observe PRP effects on RT2.
- Practice block (32 trials) precedes the main block (200 trials).
- Metrics include accuracy, RT1, RT2, and detection of premature responses for comprehensive analysis.
References
- Pashler, H. (1994). Dual-task interference in simple tasks: Data and theory. Psychological Bulletin, 116(2), 220-244. 10.1037/0033-2909.116.2.220
- Welford, A. T. (1952). The "psychological refractory period" and the timing of high speed performance - A review and a theory. British Journal of Psychology, 43, 2-19.
- Sigman, M., & Dehaene, S. (2005). Parsing a cognitive task: A characterization of the mind's bottleneck. PLoS Biology, 3(2), e37. 10.1371/journal.pbio.0030037
Related Experiments
Hick's Law Experiment
FeaturedInvestigates how the number of choices affects decision-making time, a classic study in cognitive psychology.
Stroop Effect Experiment
FeaturedExamines cognitive control by testing interference between naming colors and reading words.
Negative Priming Experiment
FeaturedExplores how ignored stimuli affect subsequent responses, revealing attentional suppression mechanisms.
Learn More
APM Test - Actions Per Minute
FeaturedMeasure your clicking speed and visual reaction time. Click numbers from 50 to 1 as fast as possible!
Free IQ Test
FeaturedTest your intelligence quotient with this free IQ test covering pattern recognition, logical reasoning, and spatial skills.
Cognitive Processing and Performance Mindset Scale
FeaturedAssess cognitive processing and performance mindset across standard dimensions.
Frequently Asked Questions
Have another question? Let us know.
What is PRP?
When two tasks occur close together, processing of the second waits, delaying RT.
What does the PRP effect look like?
When two stimuli arrive close together, the response to the second is delayed — most severely at the shortest stimulus-onset asynchronies.
Why does the second task slow down?
The central-bottleneck account holds that stages such as response selection can process only one task at a time, so the second task waits its turn.
What does this mean for multitasking?
It is behavioral evidence for a structural limit: two speeded decisions cannot fully overlap, which is why divided attention costs both time and accuracy.
About This Experiment
This experiment is an educational adaptation for demonstration purposes. It is not a clinical diagnostic tool. Results reflect your performance in this specific session and should not be interpreted as an assessment of your cognitive abilities.
Data Privacy
Your experiment data is processed and stored locally in your browser. No data is uploaded to any server unless you explicitly export it.
