What does it mean to cooperate? In this paper we explore the effects of cooperation on heart rate. We argue that in cooperative contexts participants synchronize their heart rhythms according to two factors: the affordances of the task at hand and the gradual consolidation of collaborative practices. We instructed 6 groups of participants to construct LEGO models of six abstract notions, both individually and in groups. We employed recurrence analysis techniques to quantify the mutual adaptability of heart rates among the participants in the different tasks. During individual tasks individual heart rates synchronized both within and between groups (but not with controls), plausibly due to the affordances of the task at hand. Additionally, during collective, but not individual tasks, within group synchronization grew over time. We finally discuss how these measures of synchronization relate to the participants’ engagement in the tasks at hand.