Poster Session: Comparisons of comparisons of numerosity

Area of Science:

• Cognitive Psychology
• Visual Perception

Background:

• Numerosity adaptation is a phenomenon where exposure to a set of items influences the perception of subsequent sets.
• The bidirectionality of this adaptation (whether it shifts perception up or down) is debated.
• The comparison-of-comparisons technique is a method designed to minimize non-perceptual biases in perceptual tasks.

Purpose of the Study:

• To investigate the bidirectionality of numerosity adaptation.
• To determine if adaptation effects are symmetrical or directional.
• To validate the use of the comparison-of-comparisons technique for studying perceptual biases.

Main Methods:

• Participants performed a task involving adapting stimuli (100 or 25 dots) followed by test stimuli.
• The comparison-of-comparisons technique was employed, requiring participants to identify numerosity farthest from a reference.
• Trials were blocked by adaptation numerosity to isolate adaptation effects.

Main Results:

• Significant downward bias in numerosity perception was observed with 100-dot adapting stimuli.
• This downward bias confirmed the effectiveness of the paradigm in inducing adaptation.
• No significant upward or downward bias was detected with 25-dot adapting stimuli.

Conclusions:

• Numerosity adaptation appears to be unidirectional, specifically inducing a downward bias with high adapting numerosities.
• The comparison-of-comparisons technique is suitable for demonstrating adaptation-induced perceptual biases.
• Further research is needed to fully understand the mechanisms and conditions influencing numerosity adaptation directionality.