Credible signalling and social bonds: Ultimately drawing on the same idea.

The hypotheses in both target articles rely implicitly on much the same logic. For a "social-bonding" device to make sense, there must be an underlying reason why an otherwise-arbitrary behaviour sustains alliances - namely, credible signals of one's value to partners. To illustrate our points, we draw on the parallels with supposed bonding behaviours in nonhuman animals.