On experimental tests for studying altruism in capuchin monkeys

Area of Science:

• Primate behavior
• Animal cognition
• Evolutionary psychology

Background:

• Altruism, defined as benefiting others without direct actor benefit, is a complex prosocial behavior observed in various species.
• While altruism is documented in many animals, evidence in tufted capuchin monkeys remains inconclusive, necessitating further investigation.
• Existing experimental paradigms for studying altruism in primates, such as great apes, offer potential models for capuchin research.

Purpose of the Study:

• To investigate the altruistic capabilities of tufted capuchin monkeys using two experimental paradigms adapted from great ape studies.
• To determine if capuchins display altruistic behaviors under varying costs associated with the action.
• To assess the influence of recipient requests on altruistic actions in capuchins.

Main Methods:

• Two experiments were conducted with pairs of capuchin monkeys, employing distinct tasks with differing costs for altruistic actions.
• Experiment 1 involved a costly operant sharing task where one monkey could allow another access to food.
• Experiment 2 used a less costly helping task where one monkey could assist another in accessing food.

Main Results:

• Capuchin monkeys showed an unwillingness to share food in the high-cost operant sharing task.
• Monkeys demonstrated potential altruistic helping behavior in the low-cost task, particularly when prompted by the recipient.
• Results suggest a nuanced expression of altruism in capuchins, dependent on situational costs and social cues.

Conclusions:

• Tufted capuchin monkeys may exhibit selective altruism, favoring helping over costly sharing.
• The findings suggest that capuchins' altruistic tendencies are influenced by the cost of the action and recipient solicitation.
• While preliminary due to sample size and procedural limitations, the study provides a foundation for refining methods to study primate altruism.