Much of our everyday lives, as anyone willing to consider the issue will be aware, consists of choosing between alternative courses of action. Determining which response is appropriate in a particular context is a complex issue, influenced by current motivation and past history as well as individual assessments of the desirability of each alternative. Sometimes our actions are selected voluntarily, based on an internal assessment of what is the optimal option to choose, other times they are constrained by instruction or prompted by external stimuli. Nevertheless, in a static environment, where the relationships between what we choose to do and the concomitant consequences were fixed, such decisions would still be relatively straightforward. Unfortunately, however, we exist in a dynamic and uncertain world, cooperating and competing with others, in which the outcome of our choices can be influenced by what we and others have previously decided to do.
