Chimpanzees' socially maintained food preferences indicate both conservatism and conformity

Area of Science:

• Primate behavior
• Cognitive ethology
• Social learning in animals

Background:

• Previous research shows chimpanzees (Pan troglodytes) resist adopting new strategies.
• Existing studies often involve entirely novel behaviors, making strategy adoption difficult.

Purpose of the Study:

• To investigate chimpanzee conservatism when the new strategy uses identical behaviors but offers a different reward.
• To determine if chimpanzees conform to social models even when it leads to less preferred outcomes.

Main Methods:

• Chimpanzees observed a trained model selecting one of two tokens, each linked to a different food reward (grape or carrot).
• One group was trained to select a token for a less preferred reward (carrot), while the control group received a preferred reward (grape).
• Behavioral choices and food preferences were monitored over time.

Main Results:

• Chimpanzees conformed to the model's token choice, adopting the demonstrated strategy regardless of the associated reward.
• This conformity was observed even when the chosen strategy led to the less preferred carrot reward.
• Individual food preferences remained unchanged, indicating conservatism rather than a shift in preference.

Conclusions:

• Chimpanzees exhibit significant behavioral conservatism, adhering to established strategies even when suboptimal.
• Social learning and conformity play a crucial role in chimpanzee decision-making, overriding individual preferences.
• This conservatism, while seemingly inefficient, may serve adaptive functions such as maintaining social cohesion within groups.