JOINT ACTION AWARENESS IN MACAQUES DURING A MULTIPLAYER VIDEO-GAME CONTEXT

In behavioral neuroscience, research in nonhuman primates often relies on video-game–like paradigms, including studies of social interaction and joint action. In social studies, establishing whether animals monitor their partner and are aware of their reciprocal interactions in these abstract laboratory settings is essential for interpreting the processes underlying cooperative performance. Here, we examined spontaneous head-orienting behavior in two macaques performing a cooperative visuomotor task under highly controlled conditions. The animals sat side by side with their heads unrestrained and used isometric joysticks to control their respective cursors displayed on a shared screen. Depending on trial instructions, they performed either individual actions (SOLO action, SA) or joint actions (JA) to obtain a reward. We quantified spontaneous head rotations toward the partner as an ethologically relevant behavioral indicator of social monitoring. Partner-directed head turns occurred more frequently during JA than during SA trials. Crucially, their rate increased with the number of errors made by the partner during JA trials. Together, these findings indicate that macaques monitor their partner during abstract, computer-mediated cooperative interactions and that this monitoring is driven by the partner’s performance. Such spontaneous, context-specific orienting toward the partner supports the interpretation that macaques are aware of their dyadic engagement, even in video-game-like settings. Our results therefore highlight the suitability of controlled visuomotor paradigms for investigating the cognitive-motor processes underlying joint action in nonhuman primates.