Feature-based search asymmetries in pigeons and humans

Area of Science:

• Cognitive Psychology
• Comparative Cognition
• Visual Perception

Background:

• The search-asymmetry effect is a well-documented phenomenon in human visual search.
• This effect describes faster search times when the target possesses a unique feature compared to when distractors possess that feature.

Purpose of the Study:

• To investigate whether pigeons exhibit the search-asymmetry effect observed in humans.
• To compare visual search strategies between pigeons and humans using simple line forms.

Main Methods:

• Both pigeons and human participants performed visual search tasks with identical distractors.
• Stimuli varied in the presence or absence of a feature (line or gap) on the target or distractors.
• Response times were recorded for both species, with humans using light pens or verbal reports.

Main Results:

• Human subjects consistently demonstrated the search-asymmetry effect across conditions.
• Pigeons failed to exhibit search asymmetry, regardless of whether the feature was on the target or distractors.
• Search speed in pigeons did not improve when the target possessed the unique feature.

Conclusions:

• Pigeons and humans appear to differ in their early visual processing mechanisms.
• The findings suggest that features processed by pigeons may differ from those salient to humans in search tasks.
• Long-term practice may influence or eliminate search asymmetry in pigeons.