Discussion summary by Elles:
In the paper Fawcett et al. describe the behavioral gambit, which in an assumption conceptually closely related to the phenotypic gambit used by behavioral ecologists. The phenotypic gambit states that genetic architecture does not constrain the different phenotypes that can evolve. The behavioral gambit is the assumption that psychological mechanisms do not constrain the behavior that can evolve.
The approach that is usually taken by behavioral ecologists is an optimality theory to predict the behavior of an organism. For example, the time a forager takes to collect food before returning to the nest can be predicted by calculating the optimal solution. However, not all animals always choose for the optimal solution.
Fawcett et al. state that it is important for researchers to keep in mind that they use this behavior gambit for two reasons: This assumption sometimes fails, and new insights into adaptive behavior may be obtained if the assumption is not made or checked.
The reason why this assumption does not always hold is because there is no selection pressure on behavioral outcome, but the psychological mechanism that determines this behavior. This psychological mechanism makes behavior flexible as well, as there is no evolved action to take in every situation, but more general rules that can be learned to deal with a variety of situations.
There is consensus in our group that this is an important paper. Although the behavioral gambit will probably withstand in most situations, it is crucial that this is checked and at least be kept in mind. Although in a lot of cases the reason why it has not been checked yet is because psychological mechanisms are very hard to observe, and behavior is not. To find out what kind of learning rule is used it will take a lot of experiments to see when and when not the rule works optimally.
A second remark made on this paper is that they are using the terms learning rule and psychological mechanism interchangeably. However, a learning rule is just another proxy of how the psychological mechanism might work and this too is an assumption that might not hold up every time. If you go even further you might say that psychological mechanisms are no different from brain physiology, and behaviors should then be explained from this level. An example that was brought up is affiliative behavior in promiscuous montane voles and monogamous prairie voles that is regulated by a single gene for a vasopressin receptor (Young, Nilsen, Waymire, MacGregor, & Insel, 1999). Of course, in most cases behavior is not regulated by single genes, and even if it were, this still does not clarify the exact total physiological mechanism that is at work.
So, in conclusion, it is important to be aware that assumptions are being made. Sometimes the behavioral gambit does not uphold, and it is useful to think in terms of the general learning/ behavior rules and organism might follow. Event though this is just another proxy for psychological mechanisms, which is a consequence of the brain physiology, which is most of the time not a useful frame to predict behavior. Just like thinking about interactions at atomic levels in the brain has lost almost all usefulness. in predicting the behavior of an animal. The frame you work from is dependent on the subject, just as long you don’t take the assumptions for granted.