this paper is on procedures whereby new (e.g., juvenile) members of a population could learn to communicate with the other members by observing their communicative behavior. Two apparently distinct issues are relevant to the evaluation of such learning procedures. First, the procedure must enable the new members to accurately acquire the communication system of the population, even though their observations may be limited, noisy, or otherwise misleading. Second, the learning procedure used by its new members will affect the population's communication system over time. The use of a particular procedure might result in the population's communication increasing in coordination, ultimately yielding a nearly optimally coordinated system. If a learning procedure were to satisfy both criteria, it could explain how learned communication systems are maintained over time, as well as how they are established in the first place.

Human language is unique among the communication systems of the natural world. The vocabulary of human language is unique in being both culturally-transmitted and symbolic. In this paper I present an investigation into the factors involved in the evolution of such vocabulary systems. I investigate both the cultural evolution of vocabulary systems and the biological evolution of learning rules for vocabulary acquisition.

At first glance, birds and non-human primates (hereafter primates) seem very different. Birds have beaks, feathers, produce offspring that gestate in shells, and can fly. Primates are covered in hair, have forward facing eyes and grasping hands, and while some are arboreal, none of them can fly. Although there

Theories of language evolution typically attribute its unique structure to pressures acting on the genetic transmission of a language faculty and on the cultural transmission of language itself. In strongly biological accounts, natural selection acting on the genetic transmission of the language faculty is seen as the key determinant of linguistic structure, with culture relegated to a relatively minor role. Strongly cultural accounts place greater emphasis on the role of learning in shaping language, with little or no biological adaptation. Formal modelling of the transmission of language, using mathematical or computational techniques, allows rigorous study of the impact of these two modes of transmission on the structure of language. In this thesis, computational models are used to investigate the evolution of symbolic vocabulary and compositional structure. To what extent can these aspects of language be explained in terms of purely biological or cultural evolution? Should we expect to see a fruitful interaction between these two adaptive processes in a dual transmission model?

journal homepage: www.elsevier.com/locate/yanbe

Abstract Some animals have the cognitive capacity to diVerentiate between diVerent species of predators and generate diVerent alarm calls in response. However, the presence of any addition information that might be encoded into alarm calls has been largely unexplored. In the present study, three similar-sized human females walked through a Gunnison’s prairie dog (Cynomys gunnisoni) colony wearing each of three diVerent-colored shirts: blue, green, and yellow. We recorded the alarm calls and used discriminant function analysis to assess whether the calls for the diVerent-colored shirts were signiWcantly diVerent. The results showed that the alarm calls for the blue and the yellow shirts were signiWcantly diVerent, but the green shirt calls were not signiWcantly diVerent from the calls for the yellow shirt. The colors that were detected, with corresponding encoding into alarm calls, reXect the visual perceptual abilities of the prairie dogs. This study suggests that prairie dogs are able to incorporate labels about the individual characteristics of predators into their alarm calls, and that the complexity of information contained in animal alarm calls may be greater than has been previously believed.

journal homepage: www.elsevier.com/locate/anbehav

journal homepage: www.elsevier.com/locate/yanbe Social experience modifies behavioural responsiveness to a preferred