Rudimentary empathy in macaques' social decision-making

Area of Science:

• Primate behavior
• Social cognition
• Comparative psychology

Background:

• Prosocial behaviors are crucial for social cohesion and fitness in primate groups.
• Understanding the motivations behind nonhuman primate social interactions is an ongoing research area.
• Previous studies have explored primate sociality, but the underlying decision-making processes require further investigation.

Purpose of the Study:

• To investigate whether macaque monkeys consider the welfare of their peers when making decisions.
• To examine the consistency of prosocial motivations across different types of social outcomes (rewards and punishments).
• To identify behavioral markers associated with prosocial decision-making in macaques.

Main Methods:

• A partner-dependent choice task was designed where two macaques alternated decisions affecting themselves or their partner.
• Outcomes included delivering a mild airpuff (aversive) or granting juice rewards (pleasant).
• Behavioral markers such as mutual gaze and eye blinking were recorded and analyzed in relation to decisions.

Main Results:

• Macaques predominantly chose to avoid delivering an airpuff and to provide juice rewards to their partner.
• Consistent decision-making patterns were observed across both reward and punishment scenarios, indicating coherent motivations.
• Prosocial decisions were linked to increased mutual gaze and empathic eye blinking, while negative decisions showed reduced responses.

Conclusions:

• Macaque monkeys exhibit prosocial decision-making, factoring in their partners' welfare.
• These decisions are driven by an intrinsic motivation for social affiliation, reinforced by vicarious experiences.
• Specific social behaviors serve as reliable indicators of prosocial and antisocial decision-making tendencies.