Evolutionary Conditions for the Emergence of Communication

Communication plays a central role in the biology of most species (MaynardSmith and Szathmàry (1997)), particularly in social species where it allows for the transfer of vital information among group members, thereby ensuring ecological success (Wilson (1975)). Understanding communication and its evolution are therefore essential to our understanding of the mechanisms driving social behavior. Despite extensive efforts toward this end, the conditions conducive to the evolution of communication and the paths by which reliable systems of communication become established remain largely unknown (Maynard-Smith and Harper (2003)). This is a particularly challenging problem because efficient communication requires tight co-evolution between the signal emitted and the response elicited. A powerful means to study the evolution of communication would be to conduct experimental evolution (see e.g., Griffin et al. (2004); Fiegna et al. (2006)) in a species with elaborate social organization. Unfortunately, highly social species are not amenable to such experiments because they typically have long generation times and are difficult to breed in the laboratory. In this chapter we report on an experimental system using groups of foraging robots, which was designed to circumvent this problem. Robots could forage in an environment containing a food and a poison source that both emitted red light and could only be discriminated at close range (see Fig. 1, right). Under such circumstances, transmitting information on food and poison location can potentially increase foraging efficiency. However, such communication also incurs direct costs to the signaler, since signaling results in higher robot density around the food. Due to spatial constraints around the food (a maximum number of robots can feed simultaneously), high robot density increases competition and interference, resulting in robots sometimes pushing each other away from the food. Thus, while beneficial to other group members, signaling of a food location effectively constitutes an altruistic act (Hamilton (1964, 1996)) because it decreases the food intake of signaling robots. This setting therefore mimics the natural situation where communicating almost invariably incurs costs in terms of signal production or increased competition for resources (Zahavi and Zahavi (1997)).