Approaches to understanding natural behavior.

Many important questions cannot be addressed without considering vision in its natural context. How can we do this in a controlled and systematic way, given the intrinsic diversity and complexities of natural behavior? We argue that an important step is to start with better measurements of natural visually guided behavior to describe the visual input and behavior shown in these contexts more precisely. We suggest that, to go from pure description to understanding, diverse behaviors can be treated as a sequence of decisions, where humans need to make good action choices in the context of an uncertain world state, varying behavior goals, and noisy actions. Because natural behavior evolves in time over sequences of actions, these decisions involve both short- and long-term memory and planning. This strategy allows us to design experiments to capture these critical aspects while preserving experimental control. Other strategies involve progressive simplification of the experimental conditions, and leveraging individual differences, and we provide some examples of successful approaches. Thus, this article charts a path forward for developing paradigms for the systematic investigation of natural behavior.