The HED Task Catalog is under development. IDs are not stable until formal release. Comments are welcome at github.com/hed-standard/hed-task/issues.

Psychological Refractory Period Task

HED task ID: hedtsk_psychological_refractory_period

Family: Motor performance and speeded response tasks

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

An experiment is an instance of this task when its procedure matches, it manipulates at least one of the listed variables, and it records at least one of the listed measures.

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

Named versions that change what the participant experiences or does. The identifier of a variation is hedvar_<task>__<variation>.

Variation

Description

Justification

Standard Auditory-Visual PRP

hedvar_psychological_refractory_period__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

hedvar_psychological_refractory_period__visual_visual_prp

Both stimuli are visual; requires spatial separation to avoid confusion.

Both stimuli visual; tests modality effects on bottleneck

Variable SOA Design

hedvar_psychological_refractory_period__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

hedvar_psychological_refractory_period__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

hedvar_psychological_refractory_period__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

hedvar_psychological_refractory_period__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 is designed to engage the following processes:

Key references

  • Pashler, H. (1994). Dual-task interference in simple tasks: Data and theory. Psychological Bulletin, 116(2), 220–244. (DOI, PubMed)

  • Pashler, H., & Johnston, J. C. (1998). Attentional limitations in dual-task performance. In H. Pashler (Ed.), Attention (pp. 155–189). Psychology Press.

Further references

  • 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. (DOI, PubMed)

  • Sigman, M., & Dehaene, S. (2008). Brain mechanisms of serial and parallel processing during dual-task performance. Journal of Neuroscience, 28(30), 7585–7598. (DOI, PubMed)

  • 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.

  • 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.