Do Different Prior Contest Experiences Interference with Each Other?

[[abstract]]Considerable evidence indicates that experience in prior contests influences how individuals interact with each other in subsequent contests: a previous loss causes an individual to behave more submissively, while a previous win causes an individual to behave more aggressively. These experience effects are thought to be caused by individuals altering their estimated fighting ability and costs of fighting after wins and losses. The value of information from past experiences should be affected by the reliability of the information, which could decrease with the passage of time (time-driven decay) or with the occurrence of new events (event-driven decay). Although the time-driven decay of experience effects on contest behavior has been studied, the event-driven decay has never been addressed. Using Kryptolebias marmoratus as the study animal, I tested whether a new experience causes the effect of a previous losing experience to decay. I gave each individual two experiences and staged 2 different types of contests: LL-NL (LL individuals fighting against NL individuals) and LN-NN. If the second losing experience causes the effect of the first losing experience to decay, I would expect the LL individuals in the LL-NL contests to be more aggressive and win more contests against their opponents than the LN individuals in the LN-NN contests. A total of 195 LL-NL and 194 LN-NN contests were staged and LL individuals (in LL_NL contests) won significant more contests than the LN individuals (in LN_NN contests). This result suggests that the two losing experiences of the LL individuals interfere with each other such that the effect of the LL treatment appears to be smaller than the summed effect of a penultimate and a recent losing experience. Nonetheless, this interference effect was only observed in contests between contestants that had lost their last fight (more than a month ago) before being used for this experiment. The results also showed that there are loser effects in the LL_NL and LN_NN contests. The duration of LL_NL contests was shorter than that of LN_NN contests. Escalation rate was lower in LL_NL contests than in LN_NN contests. Besides, probability of early retreat in LL_NL contests was higher than in LN_NN contests. Individuals with more recent losing experiences tended to behave more submissively and retreat sooner.