Figure 3. Differences of network properties between male and female players (M − F) on the last day 856.

(a) average degree , (b) clustering coefficient C, (c) average neighbour degree . Females have higher average degrees in PM and trade networks, as well as a higher clustering coefficient in trades, but considerably lower for PMs. (d) reciprocity R between male-male and female-female links on the last day 856. Females are substantially more reciprocal in friendships and trades. Errorbars denote the standard deviations of the network measures obtained from the 8 male control groups (each of the size of the female group), illustrating the substantial differences. A statistical t-test supports these results by significant rejection of the equal means hypothesis. For definitions see Methods.