Imitative learning occurs when an individual acquires a novel action as a result of watching another individual produce it. It can be distinguished from other, lower-level social learning mechanisms such as local enhancement, stimulus enhancement, and contagion (see Imitation: Definition, Evidence, and Mechanisms). Most critically within this context, it can also be distinguished from emulation in which an individual learns about the affordances and/or causal properties of the objects involved in a demonstration rather than the particular actions used by the model. In stark contrast to emulation, the term “over-imitation” is sometimes used to refer to action copying that is so faithful that it includes the casually irrelevant and unnecessary actions of a model (technically, however, this term is better reserved for cases in which a learner copies a model’s unnecessary actions even when they have been explicitly instructed not to do so).
Human culture is qualitatively different from that of any other species. The depth and breadth of our cultural traditions dwarf those of even our closest living primate relatives, chimpanzees. Researchers have thus far documented a total of a few dozen cultural differences between different chimpanzee groups (Whiten et al. 2001). Humans clearly go far beyond this: the cultural variation between human groups is practically limitless, from differences in the ways in which we speak, eat and dress, to differences in the cultural rituals we engage in. Learning how group members in general tend to do things is thus extremely important for human cultural transmission. Copying group members’ actions is consequently much more important for us than it is for chimpanzees.
Empirical research has shown that a major difference between social learning in humans and chimpanzees is that, whereas chimpanzees tend to copy outcomes (that is, emulate), humans tend to copy actions, and do so from early in development. Many studies, from many different labs, have shown that young children typically copy the actions others demonstrate faithfully. They do this even when the model’s actions are clearly unnecessary or causally irrelevant, when it results in less efficient performance on their part, and, on occasion, even when they are explicitly told not to. In contrast to the behavior of young children, chimpanzees spontaneously copy others’ actions only rarely.
Beyond copying actions versus outcomes, there are several other, even more deeply social aspects of imitation that appear to be unique to humans. As we will see below, these all involve the motivation to be like other members of the group, and the pressures, coming both from within individuals and from the group itself, to do things the way “we” all do them. When compared to social learning in chimpanzees (as well as to social learning in other animal species), it is clear that imitative learning in humans is a profoundly social process.
As outlined above, the key differences between imitative learning in humans and animals appear to reside in the social motivations and social pressures which influence human copying behavior. One situation in which the social pressure to imitate is particularly clear is teaching. When engaged in a teaching situation, knowledgeable members of the group often mark information that is important for the learner to reproduce with social cues such as ostensive eye contact. Recent research has shown that even infants are sensitive to these teaching cues and motivated to respond to them. Gergely and Csibra (2006), for example, report an experiment in which 14-month-olds infants were presented with a demonstration in which a model performed an unusual action: turning on a light box using her head rather than her hand. In one condition, the model indicated that this information was important for the infants by marking it with ostensive eye contact. In the other condition, the model did not provide any teaching cues. Results showed that infants were significantly more likely to copy the unusual action when it was accompanied by ostensive eye contact.
Further research has shown that children do not merely experience social motivation and pressure to imitate on a dyadic level (as in many teaching situations) but also do so on a group level. This group-level aspect of imitation is evident in normativity. When a knowledgeable group member demonstrates an action for a child, the child often learns it normatively, as the way group members in general ought to behave. In one of the earliest illustrations of this, Rakoczy et al. (2008) presented 3-year-old children with demonstrations of how to play a novel game. Once children had learned the game, a puppet asked to join in but then performed the relevant actions incorrectly. Children protested against this violation of the norms of the game, attempting to enforce the learned norms on the puppet. The children in this study thus demonstrated that they had internalized the relevant norms and expected other group members to adhere to them as well.
Another area in which the group-level aspects of imitation are particularly clear is conformity. In adults at least, conformity is a powerful mechanism through which cultural norms, behaviors, and attitudes are learned and maintained. Recent research has shown that young children also conform to the behavior of those around them. In fact, the motivation and pressure to conform is so great that children conform to the claims of their group members even when those claims are clearly false. For example, when presented with an Asch-style test of conformity, 4-year-olds conform to the majority’s opinion on almost 40% of trials (Haun and Tomasello in press). Evidence that social motivations and pressures underlie much of children’s “extreme” copying come from findings like the following: children conform more in public than in private (Haun and Tomasello in press) and increase how closely they copy others when they have a goal to affiliate (Over and Carpenter 2009).
In contrast to human children, there is little evidence that chimpanzees experience either social motivation or social pressure to imitate. For example, chimpanzees do not appear to be sensitive to either social-teaching cues, such as ostensive eye contact, or to social norms. Recently, however, there has been some suggestion that chimpanzees show conformity to the behavior of their group members. That is, when individual chimpanzees are trained how to use a particular technique in order to obtain food and then placed back into their social group, the learned technique tends to spread to other group members (Whiten et al. 2005). However, this is most likely a product of lower-level social learning mechanisms such as emulation, rather than (internally or externally felt) social pressure to conform to the behavior of group members.
Open questions, of course, remain. In terms of developmental research, one of the most pressing questions for future research is the extent to which the intergroup context influences imitation. For example, do young children learn actions more readily and more deeply from ingroup members than from outgroup members? In terms of comparative research, one open question relates to enculturation. Previous research has suggested that extensive human contact increases chimpanzees’ tendency to copy actions. Does this process of enculturation increase the social motivations and pressures chimpanzees feel to imitate? Other open questions relate to imitative learning in other animal species. Previous research has shown that a great many animal species including, but not limited to, rats, songbirds, dolphins, and whales are capable of social learning (see Social learning in animals). To what extent (if at all) does the social context influence copying in these other animal species?