goxpyriment

Psychological Refractory Period (PRP)

Implements the classic Psychological Refractory Period paradigm. Two tasks overlap in time with a variable Stimulus Onset Asynchrony (SOA). The PRP effect — the finding that RT to Task 2 increases as SOA decreases — demonstrates a central processing bottleneck: the brain cannot simultaneously execute two decision-making processes.

Task design

Task Stimulus Response
Task 1 (auditory) Low tone (400 Hz) or High tone (900 Hz) S = Low, D = High
Task 2 (visual) Letter ‘A’ or letter ‘B’ K = A, L = B

SOA values (time between Task 1 and Task 2 stimuli): 50, 100, 200, 400, 800 ms, randomly interleaved.

Running

go run main.go          # fullscreen
go run main.go -d       # windowed (development)
go run main.go -d -s 1  # windowed, subject ID 1

Flags

Flag Default Description
-d off Development mode: windowed 1024×768
-s 0 Participant ID

Controls / Response keys

Key Meaning
S Task 1 — Low tone
D Task 1 — High tone
K Task 2 — Letter A
L Task 2 — Letter B
Escape Quit

Respond to each task as quickly as possible. Task 1 must be responded to before Task 2.

Output

Data are saved to goxpy_data/ as a .xpd file. One row per trial, recording SOA, Task 1 stimulus and RT, Task 2 stimulus and RT, and whether each response was correct.

References

Pashler, H. (1994). Dual-task interference in simple tasks: Data and theory. Psychological Bulletin, 116(2), 220–244. https://doi.org/10.1037/0033-2909.116.2.220