HANDICAPS ARE UNNECESSARY FOR HUMAN COMMUNICATION

Evolutionary stability is the defining problem of animal signaling theory (Maynard Smith & Harper, 2003). If it pays a signaler to signal dishonestly, at least on average, then we should expect dishonest signals to evolve. If this occurs, the receiverOs best reaction is, again on average, simply to ignore signals from these signallers, and so we should expect this indifference to evolve too. The end result is that the system has collapsed, and no further communication takes place. Under what circumstances does this outcome not come to pass? Animal signaling theory has identified a number of different ways in which this outcome is avoided (ibid.). One general, high-level taxonomy of these alternative is to distinguish between common interest, indices, deterrents, and handicaps (Scott-Phillips, 2014). Common interest is when there is no incentive for dishonesty in the first place. Indices are signals that cannot be faked, because of some causal relationship between the signal and the signified. Deterrents are costs paid by dishonest signalers if their dishonesty is discovered; loss of reputation is one example. Handicaps are a particular type of index, in which honest signalers pay costs in order to guarantee the honesty of the signal. With handicaps it is signal production itself that is costly, whereas with deterrents the costs arise from the consequences of the production of the signal. The literature on human communication often states that handicaps are necessary for evolutionary stability, but the actual mathematical models show that this is simply not true (Lachmann et al., 2001; Szamado, 2011). Handicaps are sufficient to stablise communication, but not necessary (ibid.). However, this message has yet to permiate the literature on human communication, which frequently claims otherwise (Scott-Phillips, 2014). I will present experimental results which show how human communication can be kept stable without handicaps. Participants played in anonymous groups of 16, randomly divided into 8 player 1s and 8 player 2s. They played 16 rounds of games, 8 against each player of the opposite type i.e. each player 1 played each player 2 twice. Each HANDICAPS ARE UNNECESSARY FOR HUMAN COMMUNICATION