Where does the processing of size meet the processing of space?

Area of Science:

• Cognitive Psychology
• Human-Computer Interaction
• Neuroscience

Background:

• Previous research established a stimulus-response (S-R) compatibility effect between physical stimulus size and response location.
• This effect manifests as faster left (right) responses to small (large) stimuli, compared to reversed assignments.

Purpose of the Study:

• To investigate the locus of interactions between the processing of stimulus size and spatial locations.
• To determine whether size-location interactions occur at a perceptual or response selection level.

Main Methods:

• Experiment 1: Participants vocalized responses to stimuli varying in color, size, and location, excluding response-related spatiality.
• Experiment 2: Participants used spatial key-presses (left/right hand) to respond to stimulus color, and the interaction with the Simon effect was tested.

Main Results:

• Experiment 1 revealed no size-location congruency effect when responses lacked spatiality (color-naming task).
• Experiment 2 demonstrated a congruency effect with spatial responses (key-presses).
• An interaction between the size-location compatibility effect and the Simon effect was observed in a subsample with slower reaction times.

Conclusions:

• The findings suggest that the size-location compatibility effect emerges at the response selection stage.
• An extended leaky, competing accumulator model accurately describes how size-location and Simon effects arise during response selection.