Beyond fixed sets: boundary conditions for obtaining SNARC-like effects with continuous semantic magnitudes

Area of Science:

• Cognitive Psychology
• Neuroscience
• Human-Computer Interaction

Background:

• The spatial-numerical association of response codes (SNARC) effect links numerical magnitude to spatial response location.
• This effect is often attributed to a spatially organized representation of numerical magnitude in long-term memory.
• The format of this representation has been theorized to be positional, aligning with learned number sequences.

Purpose of the Study:

• To investigate whether SNARC-like effects occur for non-numerical magnitudes (size, living/nonliving status) where no canonical ordering exists.
• To test the hypothesis that positional coding is necessary for SNARC-like effects.
• To determine if space is an inherent aspect of long-term magnitude representation.

Main Methods:

• Participants (N=88 for size, N=114 for status) classified animal/object names based on size or living/nonliving status.
• Names were selected from a large set (400 items) and presented once per session.
• Responses were made using left and right manual keypresses, with response times recorded.

Main Results:

• No significant SNARC-like effect was found; the relationship between response time and relative size did not differ across left and right response sides.
• The results indicate that SNARC-like effects did not emerge for the tested non-numerical magnitudes.
• This suggests that the spatial representation of magnitude is not inherent but may depend on learned positional coding.

Conclusions:

• Space is not an inherent feature of the brain's long-term representation of magnitude.
• SNARC-like effects appear to require some form of positional coding, which is absent for magnitudes without a learned canonical order.
• The findings challenge purely spatially based models of magnitude representation and highlight the role of learned order.