Aggressive encounters lead to negative affective state in fish

Area of Science:

• Ethology
• Animal Behavior
• Neuroscience

Background:

• Aggressive encounters can lead to significant behavioral and physiological changes in animals.
• Affective states, influenced by experiences, play a role in decision-making following social interactions.
• Understanding these states is crucial for comprehending animal responses to conflict.

Purpose of the Study:

• To investigate affective states in territorial fish after aggressive encounters.
• To explore the relationship between affective state, decision-making, and bold/shy behavioral traits.
• To determine if losing an aggressive encounter influences judgment bias.

Main Methods:

• Eighteen Murray cod (Maccullochella peelii) were assessed for bold/shy traits using three tests.
• A go/no-go judgment bias (JB) test was employed, involving reward and punishment contingencies.
• Fish were housed with an aggressive conspecific for 24 hours before probe tests to assess affective state changes.

Main Results:

• Only one-third of fish successfully completed the JB training.
• Trained fish exposed to an aggressive conspecific showed pessimistic responses in probe tests.
• Bolder fish exhibited less adaptability in applying learned behaviors in novel situations compared to untrained fish.

Conclusions:

• Losing an aggressive encounter can lead to pessimistic decision-making in fish.
• Boldness may influence an individual's ability to adjust behavior based on prior social experiences.
• The study supports the hypothesis linking negative social experiences to altered affective states and decision biases.