How do (perceptual) distracters distract?

Area of Science:

• Cognitive Psychology
• Computational Neuroscience
• Human Behaviour

Background:

• Perceptual decisions are often made in the presence of distracting stimuli.
• The precise mechanisms by which distracters impact decision-making remain incompletely understood.
• Existing models propose either independent or interactive effects of distracters on choices.

Purpose of the Study:

• To investigate how irrelevant distracters modulate human choices during perceptual tasks.
• To contrast computational models explaining independent versus interaction effects of distracters.
• To determine the locus and attentional dependence of any observed distracter effects.

Main Methods:

• Human behavioral experiments measuring orientation judgments of target gratings.
• Psychophysical reverse correlation to analyze decision strategies.
• Computational modeling, comparing independent and interaction models of distracter influence.

Main Results:

• Decisions were significantly more sensitive when target and distracter stimuli were consistent.
• Evidence strongly supported an interaction model over an independent model.
• A consistency bias was observed, operating on decision values, independent of spatial attention.

Conclusions:

• Distracters interact with target information, biasing choices based on stimulus consistency.
• This bias operates at the decision level, not solely on initial sensory processing.
• A normalization framework explains how context (expectation and variability) influences perception.