 However, HBEs are anthropologists, and hence also want to describe the local causes of the overt behaviors they observe people engaging in in their fieldwork; this can be done by identifying the local manifestations of the response conditions of the strategies those people are using. Identifying these response conditions is a matter of identifying the correct functional description of those strategies (Kitcher, 1987). So how might such strategies he described? It is worth pointing out that this is quite difficult to do: what HBEs observe in the field is sets of overt behaviors in a context of a variety of ecological conditions any of which could be the response conditions. It may be far from obvious exactly why those behaviors are occurring, and which local conditions are the stimuli to which the behavior is a response. Indeed, it may not even be obvious which overt behaviors are manifestations of the same strategy. In the Ache case, what Kaplan and Hill observed is not a complete prey choice strategy, but a variety of occasions on which individuals or groups of Ache people took or did not take prey they encountered whilst out foraging, among many other sorts of foraging and other types of behaviors. The question is which, if any, of the overt behaviors on these occasions manifested a single prey choice strategy, and how these overt behaviors are related to each other and to the environmental conditions in which they occur. If human behavioral strategies are adaptations, however, then the relationships between behavioral responses and local ecological conditions that resemble those of the human evolutionary past can be expected to be locally optimal, ceteris paribus; this means that the response conditions of the strategy will (allegedly) be those (along with additional plausible selection conditions) that made the behavior fitness maximizing in the environment in which it evolved, and in any environment that is relevantly similar (Irons, 1998). This permits the HBEs to pick out the correct description of the strategy using an optimality model; identifying the causes of the Ache’s behavior in particular is a matter of identifying how the response conditions of that strategy manifest locally in their environment. 