(CIT): The Platt Laboratory combines classical ethological approaches with contemporary neurophysiological methods to study the neural bases of cognitive behavior. Charles Darwin first sketched an evolutionary approach to cognitive neuroscience: "He who understands baboon would do more toward metaphysics than Locke" (Notebook N). Understanding the neural mechanisms supporting cognition thus requires knowledge not only of the anatomy and physiology of the nervous system but also of behavioral ecology. The objective of the Platt Laboratory is to define the computational problems confronted by both human and nonhuman primates and then operationalize these problems for neurobiological study. Ultimately, attention, emotion, and decision-making reflect the operation of neural mechanisms that evolved to deal with the behavioral problems animals, including humans, have confronted in their natural environments during their evolutionary history. Current research in the Platt lab applies principles of decision theory, derived from both evolutionary ecology and behavioral economics, to study how the brain decides between different actions. Neurophysiological studies in the lab have revealed neural correlates of stimulus and movement value in parietal cortex and cingulate cortex, neural circuits implicated in attention, emotion, and decision-making. Current work is aimed at extending these approaches to the neural correlates of risk-sensitive decision-making and social evaluation. NIH Neuroscience Seminar Series.