Human children, chimpanzees, and orangutans act rationally in an adaptive collaborative choice task

Area of Science:

• Comparative psychology
• Developmental psychology
• Primatology

Background:

• Humans exhibit a unique motivation for collaboration, considered crucial for sociocognitive development.
• Debate exists on whether human collaborative motivation is an autapomorphic trait, due to limited cross-species comparisons.
• Previous studies often overlook individual flexibility and variations in collaborative tendencies within and across species.

Purpose of the Study:

• To conduct tailored comparisons of collaborative versus individual action preferences across species.
• To investigate the role of reward payoffs in motivating collaborative and individual efforts.
• To assess the flexibility of collaborative tendencies in human children and nonhuman great apes.

Main Methods:

• An adaptive testing paradigm was employed, adjusting reward payoffs based on participant choices.
• Participants included human children (4-6 years) and zoo-housed chimpanzees and orangutans.
• Preferences for collaborative vs. individual actions were compared under varying reward conditions.

Main Results:

• All three species predominantly acted as rational maximizers, prioritizing higher reward payoffs.
• Human children showed increased sensitivity to reward disparities with age.
• Chimpanzees demonstrated higher sensitivity to reward disparities than orangutans.

Conclusions:

• Human children exhibit greater flexibility in collaborative tendencies than previously assumed.
• Children, like nonhuman great apes, may frequently act as rational maximizers in collaborative contexts.
• Findings challenge the notion of uniquely human collaborative motivation, highlighting shared rational decision-making processes.