Probability and the changing shape of response distributions for orientation

Area of Science:

• Cognitive Psychology
• Neuroscience
• Visual Perception

Background:

• Spatial attention and feature-based attention are considered independent mechanisms.
• Feature attention is typically viewed as spatially invariant, benefiting single features per dimension.

Purpose of the Study:

• To investigate whether attention's benefits are location-independent, challenging existing models.
• To explore how attention influences response distributions for high-probability feature-location conjunctions.

Main Methods:

• Participants reported the orientation of visual gratings under varying feature and location probabilities.
• Analysis focused on response distributions, including kurtosis, to infer attentional effects.

Main Results:

• Participants showed improved orientation reporting for high-probability feature-location conjunctions.
• Response error distributions for these conjunctions were non-normal, exhibiting increased kurtosis.
• Increased kurtosis suggests changes in the variance of underlying neural tuning functions.

Conclusions:

• Attention may prioritize stimuli rather than solely increasing perceptual quality.
• Attentional prioritization leads to more highly accurate responses for probable targets and more very inaccurate responses for improbable ones.
• Findings suggest attention modulates neural population activity, altering discrimination function shapes.