preferring fish to meat in one instant and preferring meat to fish in another, without anything else having changed. Actions, assumptions, and individual preferences The basic premise of rational choice theory is that the decisions made by individual actors will collectively produce aggregate social behaviour. Thus, each individual makes a decision based on their own preferences and the constraints (or choice set) they face. Rational choice theory can be viewed in different contexts. At an individual level, the theory suggests that the agent will decide on the action (or outcome) they most prefer. If the actions (or outcomes) are evaluated in terms of costs and benefits, the choice with the maximum net benefit will be chosen by the rational individual. Rational behaviour is not solely driven by monetary gain, but can also be driven by emotional motives. The theory can be applied to general settings outside of those identified by costs and benefits. In general, rational decision making entails choosing among all available alternatives the alternative that the individual most prefers. The "alternatives" can be a set of actions ("what to do?") or a set of objects ("what to choose/buy"). In the case of actions, what the individual really cares about are the outcomes that results from each possible action. Actions, in this case, are only an instrument for obtaining a particular outcome. Formal statement The available alternatives are often expressed as a set of objects, for example a set of j exhaustive and exclusive actions: For example, if a person can choose to vote for either Roger or Sara or to abstain, their set of possible alternatives is: The theory makes two technical assumptions about individuals' preferences over alternatives: Completeness – for any two alternatives ai and aj in the set, either ai is preferred to aj, or aj is preferred to ai, or the individual is indifferent between ai and aj. In other words, all pairs of alternatives can be compared with each other. Transitivity – if alternative a1 is preferred to a2, and alternative a2 is preferred to a3, then a1 is preferred to a3. Together these two assumptions imply that given a set of exhaustive and exclusive actions to choose from, an individual can rank the elements of this set in terms of his preferences in an internally consistent way (the ranking constitutes a total ordering, minus some assumptions), and the set has at least one