Starlings can categorize symmetry differences in dot displays

Area of Science:

• Animal behavior
• Evolutionary biology
• Sensory ecology

Background:

• Fluctuating asymmetry (FA) estimates developmental stability and can indicate individual fitness.
• Organisms may use morphological asymmetry as a visual cue in social interactions.
• Animal perception of symmetry is crucial for understanding FA's role in nature.

Purpose of the Study:

• Investigate European starlings' ability to discriminate symmetry from asymmetry.
• Assess factors influencing symmetry perception in birds.
• Determine if starlings can generalize symmetry detection.

Main Methods:

• Operant learning experiments with wild-caught European starlings (Sturnus vulgaris).
• Discrimination tasks using random dot patterns with varying symmetry.
• Transfer tests with novel stimuli to assess generalization.

Main Results:

• Starlings showed no initial preference for symmetry or asymmetry.
• Birds learned to prefer symmetry, though learning was slower and more error-prone than in pigeons.
• Trained starlings successfully generalized symmetry discrimination to unseen patterns.

Conclusions:

• European starlings can learn to categorize visual symmetry.
• This suggests a generalized perception of symmetry in starlings.
• Findings support the possibility of birds using fluctuating asymmetry as a visual cue.