Figure 2.

Relationship between the number of friends (out degree centrality) and performance in the rope-pulling task. The number of friends and social network were based on a questionnaire before the experiment where children were asked to give the names of children they prefer to play with in their classroom including children who did not participate in the task. (a) Boxplots contrasting the number of friends averaged between the two partners according to their performance during the first trial. Failure in the first trial is shown on the left (in red in online version) and joint success on the right (in green in online version). Each dot represents a dyad of children. (b) Examples of two classroom networks in which individuals who succeeded in the first trial appear in light grey (green in online version) and who failed in dark grey (red in online version). Children who did not participate and who participants named as friends appear in grey. Arrows represent friendship between children such that bi-directional arrows represent pairs of individuals who each listed the other as a friend whereas single-headed arrows represent cases where one individual considered the other a friend while the second individual did not list the first as a friend. All networks are presented in electronic supplementary material, figure S6. Having more friends is linked to a higher success in the cooperative task. (Online version in colour.)