We experimentally test two competing theories that explain why people can coordinate their behaviour on focal points in games with multiple equilibria. The standard economics explanation is based on individual reasoning based on expectations of random behavior by others. The alternative explanation invokes team reasoning, where individuals find the best outcome for the team and act according to their role in this outcome. The results are inconsistent with best-responding to randomisation but consistent with team reasoning as the modal behaviour, though there is also unexplained heterogeneity. Increasing the difficulty of the coordination tasks produces some behaviour suggestive of response to randomisation.
COBISS.SI-ID: 1539019972
With a behavioral laboratory experiment, we investigate the complexity of behavioral strategies that people use to decide whether to help anonymous others. In a repeated helping game, donors learned if their recipients helped others in the past (1st order information) and could obtain further (2nd-order) information about these actions. A detailed analysis of individual strategies reveals that many subjects based their decisions solely on 1st-order information. However, a substantial fraction of subjects consistently considered also the 2nd-order information. Our results provide strong empirical support for the mechanisms that theoretically underpin reputation-based cooperation, and highlight pronounced variation in human cooperative strategies.
COBISS.SI-ID: 1538835908
Mate choice is often accompanied with conspicuous behaviour or morphology that can be exploited by predators. Here we explore the evolutionary consequences of a trade-off that arises naturally between mate acquisition and risk of predation and study evolution of the rate at which male prey search for mates in a population subject to a mate-finding Allee effect and exposed to either generalist or specialist predators. Since we show that the mate search rate determines the strength of the mate-finding Allee effect, we can alternatively view this as evolution of the mate-finding Allee effect in prey. Disruptive selection does not occur in populations exposed to generalist predators but is possible when predators are specialists.
COBISS.SI-ID: 1540037828
Evolutionary suicide is a riveting phenomenon in which adaptive evolution drives a viable population of strategies to extinction. Gyllenberg and Parvinen (Bull Math Biol 63(5):981–993, 2001) showed that, in a wide class of deterministic population models, a discontinuous transition to extinction is a necessary condition for evolutionary suicide. An implicit assumption of their proof is that the invasion fitness of a rare strategy is well-defined also in the extinction state of the population. Epidemic models with frequency-dependent incidence, which are often used to model the spread of sexually transmitted infections or the dynamics of infectious diseases within herds, violate this assumption. In these models, evolutionary suicide can occur through a non-catastrophic bifurcation whereby pathogen adaptation leads to a continuous decline of host (and consequently pathogen) population size to zero. Evolutionary suicide of pathogens with frequency-dependent transmission can occur in two ways, with pathogen strains evolving either higher or lower virulence.
COBISS.SI-ID: 1538031044