Various measures of size have been associated with increased likelihood of winning such agonistic encounters between decapod crustaceans. Recent social experience, in the form of 'winner' or 'loser' effects, has also been shown to alter the outcome of encounters between size-matched individuals. This study further explores the importance of social experience in crustacean agonistic encounters. Crayfish, Procambarus clarkii, of different size classes were given a series of winning or losing experiences to determine whether this would affect their likelihood of success in subsequent fights. Recent wins or losses in a series of fights did alter the likelihood of an individual winning a subsequent encounter, despite an apparent disparity in size between opponents that would otherwise serve as an accurate predictor of the outcome.