Psychological Refractory Period Task¶
HED Task ID: hedtsk_psychological_refractory_period
Also known as: PRP, Psychological Refractory Period
Two tasks presented with a short SOA; RT for the second task lengthens as SOA shortens, indexing a central response-selection bottleneck.
Description¶
Two stimuli are presented in rapid succession (S1 then S2, separated by a variable stimulus onset asynchrony or SOA), each requiring its own speeded response (R1 and R2). The robust finding is that R2 is slowed as the SOA decreases — the psychological refractory period effect — because central response-selection processes for S2 must wait until response selection for S1 is complete. Pashler (1994) provided the definitive review establishing the central bottleneck model: perceptual processing and motor execution can overlap between tasks, but response selection (choosing which response to make) represents a serial bottleneck. The PRP paradigm remains the primary tool for mapping the architecture of cognitive processing stages and understanding the limits of multitasking.
Inclusion test¶
Procedure |
Two stimuli requiring separate speeded responses are presented in rapid succession with a variable stimulus-onset asynchrony (SOA). Both responses are required. |
Manipulation |
SOA between S1 and S2 (50–1000 ms); task difficulty of each task; response modality overlap. |
Measurement |
RT2 as a function of SOA (PRP effect: RT2 slowing at short SOAs); RT1 (usually unaffected); locus of interference per bottleneck models. |
Variations¶
Variation |
Description |
Justification |
|---|---|---|
Standard Auditory-Visual PRP |
S1 = tone (classify pitch), S2 = letter/digit (classify identity); the canonical design. |
Canonical PRP: auditory then visual stimulus with variable SOA |
Visual-Visual PRP |
Both stimuli are visual; requires spatial separation to avoid confusion. |
Both stimuli visual; tests modality effects on bottleneck |
Variable SOA Design |
SOAs ranging from 50 to 1000 ms to trace the full PRP function. |
Multiple SOAs parametrically varied; standard PRP SOA manipulation |
PRP with Practice |
Extensive training to test whether the bottleneck can be eliminated or reduced. |
Extended practice changes PRP magnitude; tests dual-task automatization |
PRP with Ideomotor-Compatible Tasks |
Tasks with strong S-R compatibility (e.g., say the word you see) to test whether compatible tasks bypass the bottleneck. |
Ideomotor-compatible S-R mappings eliminate bottleneck; tests structural bottleneck theory |
Triple-Task PRP |
Three overlapping tasks to further constrain models of central processing capacity. |
Three concurrent tasks; extends bottleneck theory to three tasks |
Cognitive processes¶
This task engages the following cognitive processes:
Key references¶
{‘authors’: ‘Pashler, H.’, ‘year’: 1994, ‘title’: ‘Dual-task interference in simple tasks: Data and theory.’, ‘venue’: ‘Psychological Bulletin’, ‘venue_type’: ‘journal’, ‘journal’: ‘Psychological Bulletin’, ‘volume’: ‘116’, ‘issue’: ‘2’, ‘pages’: ‘220-244’, ‘doi’: ‘10.1037/0033-2909.116.2.220’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Pashler, H. (1994). Dual-task interference in simple tasks: Data and theory. Psychological Bulletin, 116(2), 220–244.’, ‘url’: ‘https://doi.org/10.1037/0033-2909.116.2.220’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}
{‘authors’: ‘Rohrer, D., Pashler, H., & Etchegaray, J.’, ‘year’: 1998, ‘title’: ‘When two memories can and cannot be retrieved concurrently’, ‘venue’: ‘Memory & Cognition’, ‘venue_type’: ‘journal’, ‘journal’: ‘Memory & Cognition’, ‘volume’: ‘26’, ‘issue’: ‘4’, ‘pages’: ‘731-739’, ‘doi’: ‘10.3758/bf03211393’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Pashler, H., & Johnston, J. C. (1998). Attentional limitations in dual-task performance. In H. Pashler (Ed.), Attention (pp. 155–189). Psychology Press.’, ‘url’: ‘https://doi.org/10.3758/bf03211393’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}
Recent references¶
{‘authors’: ‘Tombu, M., & Jolicœur, P.’, ‘year’: 2003, ‘title’: ‘A central capacity sharing model of dual-task performance.’, ‘venue’: ‘Journal of Experimental Psychology: Human Perception and Performance’, ‘venue_type’: ‘journal’, ‘journal’: ‘Journal of Experimental Psychology: Human Perception and Performance’, ‘volume’: ‘29’, ‘issue’: ‘1’, ‘pages’: ‘3-18’, ‘doi’: ‘10.1037/0096-1523.29.1.3’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Tombu, M., & Jolicoeur, P. (2003). A central capacity sharing model of dual-task performance. Journal of Experimental Psychology: Human Perception and Performance, 29(1), 3–18.’, ‘url’: ‘https://doi.org/10.1037/0096-1523.29.1.3’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}
{‘authors’: ‘Sigman, M., & Dehaene, S.’, ‘year’: 2008, ‘title’: ‘Brain Mechanisms of Serial and Parallel Processing during Dual-Task Performance’, ‘venue’: ‘The Journal of Neuroscience’, ‘venue_type’: ‘journal’, ‘journal’: ‘The Journal of Neuroscience’, ‘volume’: ‘28’, ‘issue’: ‘30’, ‘pages’: ‘7585-7598’, ‘doi’: ‘10.1523/jneurosci.0948-08.2008’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Sigman, M., & Dehaene, S. (2008). Brain mechanisms of serial and parallel processing during dual-task performance. Journal of Neuroscience, 28(30), 7585–7598.’, ‘url’: ‘https://doi.org/10.1523/jneurosci.0948-08.2008’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}
{‘authors’: ‘Strobach, T., Schubert, T., Pashler, H., & Rickard, T.’, ‘year’: 2014, ‘title’: ‘The specificity of stimulus-response and response-response compatibility effects in dual tasks’, ‘venue’: ‘Journal of Experimental Psychology: Human Perception and Performance’, ‘venue_type’: ‘journal’, ‘journal’: ‘Journal of Experimental Psychology: Human Perception and Performance’, ‘volume’: ‘40’, ‘issue’: ‘5’, ‘pages’: ‘1966–1984’, ‘doi’: None, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Strobach, T., Schubert, T., Pashler, H., & Rickard, T. (2014). The specificity of stimulus-response and response-response compatibility effects in dual tasks. Journal of Experimental Psychology: Human Perception and Performance, 40(5), 1966–1984.’, ‘url’: None, ‘source’: ‘unresolved’, ‘confidence’: ‘none’, ‘verified_on’: ‘2026-04-20’}
{‘authors’: ‘Thönes, S., Arnau, S., Wascher, E., & Schneider, D.’, ‘year’: 2021, ‘title’: ‘Boosting working memory with accelerated clocks’, ‘venue’: ‘NeuroImage’, ‘venue_type’: ‘journal’, ‘journal’: ‘NeuroImage’, ‘volume’: ‘226’, ‘issue’: ‘5’, ‘pages’: ‘117601’, ‘doi’: ‘10.1016/j.neuroimage.2020.117601’, ‘openalex_id’: None, ‘pmid’: None, ‘citation_string’: ‘Zickerick, B., Thönes, S., Kobald, S. O., Wascher, E., Schneider, D., & Küper, K. (2021). Differential effects of the psychological refractory period on early perceptual processing. Psychophysiology, 58(5), e13791.’, ‘url’: ‘https://doi.org/10.1016/j.neuroimage.2020.117601’, ‘source’: ‘crossref’, ‘confidence’: ‘high’, ‘verified_on’: ‘2026-04-20’}