Performance designates an agent’s behavioural repertoire at a point in time, typically specified by a set of conditional IF/THEN rules.

real markets involve diverse traders of bounded rationality, with different agents employing different strategies.

There is no reasonable way to assign ‘wetness’ to individual molecules; wetness is an emergent property of the aggregate.

Credit assignment.As an agent accumulates experience, it will find that some of its rules are rarely, or never, useful. If a frog flees from all moving objects it will rarely eat or mate. In order to adapt, an agent requires a means of assigning a quantity, usually called strength, that rates the usefulness of different rules in helping the agent t

analysis depends upon methods for discovering and exploiting recurring patterns in generated systems.

The agent can also modify the environment via a set of effectors (think of muscles) that translate the agent’s interior signals into actions that affect the environment (see Figure 6

‘fat-tailed’ behaviour, where rare events (e.g. mass extinctions and market crashes) occur much more often than would be predicted by a normal (bell-curve) distribution

The difficulty presented by diversity is further compounded by the conditional nature of agent actions—the actions of a typical agent are conditionally dependent upon what other agents are doing.

‘more is different’ (also discussed in Waldrop’s classic,