Size matters: non-numerical magnitude affects the spatial coding of response

Area of Science:

• Cognitive Psychology
• Neuroscience
• Magnitude Representation

Background:

• The Spatial Numerical Association of Response Codes (SNARC) effect links small numbers to left responses and large numbers to right responses.
• Recent theories propose a generalized magnitude representation encompassing various quantities beyond just numerical values.

Purpose of the Study:

• To investigate if response congruency effects, similar to the SNARC effect, extend to non-numerical quantities.
• To explore the cognitive and neural underpinnings of magnitude representation across different sensory modalities and types of stimuli.

Main Methods:

• Participants performed two-alternative forced choice discriminations using their left or right hand.
• Stimuli varied in numerical size, physical size, luminance, conceptual size, and auditory intensity.
• Response times were analyzed for congruency effects between stimulus magnitude and response hand.

Main Results:

• Significant response congruency effects were observed for numerical size, physical size, low luminance, and conceptual size, with larger magnitudes favoring right-hand responses.
• No congruency effect was found for auditory intensity stimuli.
• These findings indicate a shared representation for various visual magnitudes.

Conclusions:

• The response congruency effect is not limited to numerical magnitude but generalizes to other visual quantities.
• This supports models of a general magnitude representation system in the brain.
• The association between magnitude and spatial responses may be innate rather than learned through cultural factors like reading direction.