Many animals are highly visual. They view their world through photoreceptors sensitive to different wavelengths of light. Animal survival and optimal behavioral performance may select for varying photoreceptor sensitivities depending on animal habitat or visual tasks. Our goal is to understand what drives visual diversity from both an evolutionary and molecular perspective. The group of more than 2000 cichlid fish species are an ideal system for examining such diversity. Cichlid are a colorful group of fresh water fishes. They have undergone adaptive radiation throughout Africa and the new world and occur in rivers and lakes that vary in water clarity. They are also behaviorally complex, having diverse behaviors for foraging, mate choice and even parental care. As a result, cichlids have highly diverse visual systems with cone sensitivities shifting by 30-90 nm between species. Although this group has seven cone opsin genes, individual species differ in which subset of the cone opsins they express. Some species show developmental shifts in opsin expression, switching from shorter to longer wavelength opsins through ontogeny. Other species modify that developmental program to express just one of the sets, causing the large sensitivity differences. Cichlids are therefore natural mutants for opsin expression. We have used cichlid diversity to explore the relationship between visual sensitivities and ecology. We have also exploited the genomic power of the cichlid system to identify genes and mutations that cause opsin expression shifts. Ultimately, our goal is to learn how different cichlid species see the world and whether differences matter. Behavioral experiments suggest they do indeed use color vision to survive and thrive. Cichlids therefore are a unique model for exploring how visual systems evolve in a changing world.

Abstract relations are considered the pinnacle of human cognition, allowing analogical and logical reasoning, and possibly setting humans apart from other animal species. Such relations cannot be represented in a perceptual code but can easily be represented in a propositional language of thought, where relations between objects are represented by abstract discrete symbols. Focusing on the abstract relations same and different, I will show that (1) there is a discontinuity along ontogeny with respect to the representations of abstract relations, but (2) young infants already possess representations of same and different. Finally, (3) I will investigate the format of representation of abstract relations in young infants, arguing that those representations are not discrete, but rather built by juxtaposing abstract representations of entities.

Humans are biologically adapted for cultural life in ways that other primates are not. Humans have unique motivations and cognitive skills for sharing emotions, experience, and collaborative actions (shared intentionality). These motivations and skills first emerge in human ontogeny at around one year of age, as infants begin to participate with other persons in various kinds of collaborative and joint attentional activities, including linguistic communication. Our nearest primate relatives understand important aspects of intentional action - especially in competitive situations - but they do not seem to have the motivations and cognitive skills necessary to engage in activities involving collaboration, shared intentionality, and, in general, things cultural.