Abstract : We define five cooperation mechanisms in Particle Swarm Optimisation, loosely inspired by some models occurring in nature, and based on two quantities: a help matrix, and a reputation vector. We call these five mechanisms, respectively, Reciprocity, Vicinity, Kin, Reputation, and Anybody. It appears that Kin is better than the rest by a slight margin, but needs more parameters that have to be tuned (mutation and selection). However, Reciprocity, with less parameters, shows almost equivalent performance. The appendix gives some details about fair comparison of success rates, and the concepts of valued topology and chains of information, which may be worth further investigation.