Using Key Distance to Clarify a Theory on the SNARC.

Area of Science:

• Cognitive Psychology
• Neuroscience
• Human-Computer Interaction

Background:

• The spatial numerical association of response codes (SNARC) effect describes the tendency to respond faster to smaller numbers with left-hand keys and larger numbers with right-hand keys.
• The direct mapping account (DMA) is the leading explanation, positing a mental number line mapped to external space.

Purpose of the Study:

• To investigate whether variations in response key distance affect the spatial mapping of numbers in the SNARC effect.
• To test the flexibility of the mental number line's spatial mapping according to the DMA.

Main Methods:

• Participants completed parity and magnitude judgment tasks.
• Response key distance was systematically manipulated during these tasks.
• Statistical power and meta-analyses were conducted to ensure robust findings.

Main Results:

• Significant variations in response key distance did not alter the SNARC effect.
• Null results were confirmed by power and meta-analyses, ruling out insufficient statistical power or poor experimental design.

Conclusions:

• The spatial mapping of the mental number line to external space appears to be anchored to response location, rather than being modulated by it.
• Future SNARC effect research may not require strict control over horizontal response key separation.