Tough guys don't dance: Intention movements and the evolution of signalling in animal contests

Two animals contesting possession of a resource sometimes fight, but more often engage in aggressive displays until one or the other retreats. Game theory predicts that signals of strength or aggressive intent wifi not be heeded unless necessity or high cost make them reliable, but some animal threat displays appear to contradict this prediction. An evolutionary simulation model is presented in which two animats of variable fighting ability compete for a resource and have access to their opponent's intention movements, i.e., their real-time behavioural choices. Reliable communication of fighting ability does not evolve. The results of the simulation are used to assess conflicting theories of signalling in competitive interactions.