Why not lie? Costs enforce honesty in an experimental signalling game

Abstract

Communication depends on reliability. Yet, the existence of stable honest signalling presents an evolutionary puzzle. Why should animals signal honestly in the face of a conflict of interest? While students of animal signalling have offered several theoretical answers to this puzzle, the most widely studied model, commonly called the 'handicap principle', postulates that the costs of signals stabilize honesty. This model is the motivating force behind an enormous research enterprise that explores signal costs-whether they are physiological, immunological, neural, developmental or caloric. While there can be no question that many signals are costly, we lack definitive experimental evidence demonstrating that costs stabilize honesty. This study presents a laboratory signalling game using blue jays (Cyanocitta cristata) that provides, to our knowledge, the first experimental evidence showing honesty persists when costs are high and disappears when costs are low.

Do aggressive signals evolve towards higher reliability or lower costs of assessment?

“…However, it is not the cost of production that makes these calls reliable (Experiment 1) but the punishment by receivers. Dawkins and Guilford (Dawkins & Guilford, 1991) predicted that the costs receivers pay in assessing the signal may reduce the honesty of the signal because it may be more advantageous for receivers to accept some level of dishonesty and to pay less for the occasional assessment of cheap signals, rather than to pay for the honest assessment of costly signals (but see Polnaszek & Stephens, 2014). This study did not test the incidence of dishonest signalling; however, it indicated that the maintenance of signal honesty does not have to be a wasteful process, as predicted by Zahavi's theory, and can instead be a cheap process involving a simple frequency-dependent mechanismthe retaliation rule (Molles & Vehrencamp, 2001).…”

“…The first group includes costs that are inherent in the form of the signal and hence stabilize their reliability irrespective of the receiver's behaviour (Guilford & Dawkins, 1995;Vehrencamp, 2000), whereas the second group includes costs that arise from the receiver's response to a signal (Enquist, 1985;Adams & Mesterton-Gibbons, 1995). The most effective forms of signals for senders and the most reliable forms for receivers are usually those that are either challenging to perform or those that are made honest by a mix of developmental and production costs, that is those that are associated with an inherent cost (Polnaszek & Stephens, 2014;Searcy & Nowicki, 2005;Møller et al, 1998). However, the choice of one form of the signal instead of another appears to depend on the value of the resource involved.…”

Honest Signaling and Oxidative Stress: The Special Case of Avian Acoustic Communication

“…From an evolutionary perspective, except for arbitrary traits evolved by Fisherian runaway processes (Fisher, 1930), the game between emitters and receivers must be played by reliable counterparts that honestly signal their state (Polnaszek and Stephens, 2014), even in the case of nestlings emitting calls to communicate their state of demand (Johnstone, 1999). Signals may be honest either because they are costly to produce and only individuals in an optimal condition can sustain these costs (handicap principle; Zahavi, 1975) or because they reflect the condition of the signaler (Andersson, 1994;Hill, 2011;Garratt and Brooks, 2012), and thus its capacity to maintain optimal cellular functioning in spite of environmental challenges, as defined in Hill (2011).…”

Monkeys predict trajectories of virtual prey using basic variables from Newtonian physics

“…Questions about prospection aside, the ability to make choices based on expectations of future events is a basic skill in the repertoire of intelligent decision-makers (21–23). Those abilities guide appropriate selection of choices in foraging contexts, including under both risk and delay (24–26).…”