 Richerson and Boyd (2005, 120–22) suggest that other learning heuristics may be adaptive. One of these is standardly referred to by cultural evolutionists as conformist bias. To say that someone has conformist bias is to say that the person in question has a tendency to imitate those behaviours, beliefs or other dispositions that are present among a high frequency of individuals in the population. More precisely, this bias is usually defined as a heightened, or exaggerated, tendency to imitate the most common behaviour. That is because if (for example) the great majority of people eat with chopsticks, and just a few eat with a knife and fork, then choosing whom to imitate at random will also be likely to lead to imitation of the majority chopstick behaviour. Under these circumstances purely random choice of whom to imitate is likely to lead one to choose a chopstick user as a model. So if 70 percent of individuals in some population use chopsticks, then an imitator only has conformist bias in the strict sense favoured by cultural evolutionists if the imitator has a chance greater than 70 percent of acquiring the behaviour of chopstick use.