goxpyriment

Stroop Task

A classic cognitive interference paradigm (Stroop, 1935). Participants name the ink colour of colour words, ignoring the word’s meaning. Responses are slower and more error-prone when the word and ink colour conflict (incongruent) than when they match (congruent).

Trial structure

Fixation cross  →  Colour word  →  Response  →  ITI
    500 ms          until key       key press     500 ms

Response keys

Key	Ink colour
`R`	Red
`G`	Green
`B`	Blue
`Y`	Yellow

Design

4 ink colours × 4 word meanings = 16 combinations
Congruent: word and ink match (e.g. RED written in red)
Incongruent: word and ink conflict (e.g. RED written in blue)

Prerequisites

Go 1.25+
SDL3 development libraries (sudo apt install libsdl3-dev on Ubuntu/Debian)

Running

# Fullscreen
go run main.go

# Windowed (development / testing)
go run main.go -d

Flags

Flag	Default	Description
`-d`	off	Development mode: windowed 1024×768

Output

Data are saved to goxpy_data/ as a .xpd file (CSV with a metadata header). One row per trial:

Column	Description
`trial`	Trial number
`word`	The displayed word
`ink_color`	The ink colour
`response`	Key pressed
`rt`	Reaction time in milliseconds
`correct`	Whether the response was correct
`congruent`	`true` if word meaning matches ink colour

References

Stroop, J. R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 18(6), 643–662. https://doi.org/10.1037/h0054651

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