Active choice judgement bias reflects affective indicators in bonobos

Area of Science:

• Animal behavior and welfare science
• Cognitive ethology
• Primate psychology

Background:

• Judgement bias tasks assess how mood influences information processing.
• The Active Choice task differentiates low motivation from negative mood.
• This task had not been previously applied to zoo-housed primates or great apes.

Purpose of the Study:

• To investigate affect-derived judgement biases in zoo-housed bonobos using a novel Active Choice paradigm.
• To assess the applicability of the Active Choice task in this population.
• To explore the relationship between task performance and affective indicators.

Main Methods:

• Fourteen bonobos were trained on a visual discrimination Active Choice task.
• Seven bonobos successfully passed training criteria.
• Task outcomes were analyzed alongside affective indicators and group size.

Main Results:

• Bonobos exhibited more pessimistic choices with increased testing.
• Pessimistic choices increased on days with more abnormal behaviors.
• Optimistic choices were associated with increased play and larger social group sizes.

Conclusions:

• Active Choice task responses in bonobos appear linked to affective state changes.
• The Active Choice paradigm is a promising tool for studying bonobo mood and welfare.
• This methodology can inform theoretical and applied questions in primate cognition and welfare.