Different forms of social learning: Brief description and definitions

Many authors have differentiated several possible types of social learning, in terms of the mechanisms potentially involved. One of the most complex manifestation of social learning is “ imitation learning ”, or “ observational learning ” (Hall, 1963). Thorndike (1898) defined imitation as “learning to do an act by seeing it done". Basing on his studies of insightful behaviour of animals, Kö hler (1925) suggested that imitation demands elements of consciousness and understanding of that a modelling subject possess similar features with the learner.

The ongoing nature/nurture debate has generated the discussion about whether animals can be credited with the ability to copy their companion’s behaviour and whether this ability can be compared to the superior capacity for imitation in humans. Cognitive ethologists have focused on imitative learning because it seems likely to be implicated in the origin of human culture. In animals imitative learning can generate behavioural traditions or proto-culture. Imitation can be considered the opposite to instinctive behaviour. However, seeming displays of imitation can be triggered by instinctive responses. As we have seen in Part VII, many species can perform complex sequences of behavioural acts being triggered by a simple definite releaser. In some situations, animals can perceive such a releaser when observing conspecifics. For instance, when a pigeon sees another pigeon pecking, it also begins to peck.

In order to distinguish between imitation and other forms of behaviour, Thorpe (1956) marked out “ true imitation ” as copying a novel behaviour for which there is no instinctive tendency or for which other parsimonious explanations (Morgan, 1894) can be ruled out. The development of experimental studies of social learning has led to the acceptance of somewhat broader definitions. Thus, according to Heyes (1993), imitation occurs when observers learn about responses, actions, or patterns of behaviour as a direct result of conspecific observation. To be more precise, the observer will learn to execute a behaviour that is topographically similar to that performed by the conspecific. Call and Tomasello (1995) insist that for “true” imitation to occur the observer needs both to recognise the goal of the demonstrator and to realise that reaching this goal is only possible by copying the acts of the demonstrator.

There is the distinction between imitation and mimicking. Mimicking is said to have occurred when the response that is copied does not lead to an immediate, tangible reward. Imitation will be used to refer to responses that have been copied, and that lead to a reward. In mimicking, the observer copies the action precisely but does not understand the goal of the model. It is important to note that both mimicking and imitation demand that the learner has to translate acts and movements of the demonstrator in relations with its own body and movements.

A striking example came from Moore’s (1992) experiment with the African grey parrot that displayed capacities to mimic humans. The experimenter spent a few minutes every day with the parrot in its room. During this period, the experimenter would utter a word or phrase, perform a stereotyped movement in front of the parrot, and then leave. A videotaped record of the parrot’s behaviour revealed that during the periods that it was alone, it mimicked both the utterance and the action of the experimenter. For example, on leaving the room the experimenter waved good bye and said “ciao”. After a year the bird was heard to say “ciao”, and at the same time it waved a foot in the air. As this action was never performed in the presence of the human, its repeated occurrence was definitely not influenced by possible reward. This mimicking behaviour is rather sophisticated, in particular, because the parrot’s view of its own leg would be very different from the sight of the experimenter waving, before waving could be copied, some transformation of the visual memory of the experimenter’s response would be needed, and how this transformation might take place is not known (Pearce, 2000).

Mimicking can help social animals to acquire skills involving tools, and it also serves social functions. Seyfarth and Cheney (2002) have described how monkeys use mimicking in their Machiavellian inter-relations within groups. For instance baboons attract attention of other group members by mimicking fighting calls of highly ranked individuals. Mimicking also plays an important role in communication. Certain birds, as we have seen in Part VII, learn their songs by mimicking adult birds. The ability to mimic acoustic signals underlies vocal learning in birds and marine mammals. Recently the advanced ability to mimic acoustic signals has been discovered in elephants. One African zoo elephant reproduced sounds of trucks, and another mimicked acoustic call of the Asian elephant (Pool, 2005). Researcher have appreciated advanced abilities of apes for mimicking when teaching them elements of human gesture sign language (Wallmann, 1992; see details in Part IX).

The power of simpler than “true imitation” forms of social learning has been underestimated for a long time. “Social learning” in its recent meaning includes a wide range of categories of different levels of complexity. Several phenomena that were once seen as clearly imitative have since been explained in terms of simpler mechanisms resembling imitation.

Contagious behaviour is exemplified by a rule such as “if others are fleeing, flee also”. The idea is that the stimuli produced by the performance of a particular behaviour serve as triggers for others to behave in the same way. Possible examples of contagious behaviour include flight responses, movements in flocks or shoals, and chorusing by birds, frogs, and dogs. Laughing and yawning are excellent examples of contagious behaviour in humans (Provine, 1996). Zentall (1996) argues that contagious behaviour must have a genetic basis, i.e. it must involve the triggering on of the instinctive response.

Social facilitation, in its wide meaning is defined as an enhancement of performance of definite behaviour when another person is present. Originally, the theory of social facilitation was intended by Zajonc (1965) to explain the effects of an audience on human performances. Zajonc (1965) argued that the presence or action of the demonstrator might affect the motivation state of the observer that eventually leads to better performance. Applying the logic of social facilitation to ethology, Clayton (1978) defines social facilitation as an increase in the frequency of a behavioural pattern in the presence of others displaying the same behavioural pattern at the same time. She suggests that social facilitation in animals could be due to the reduction of isolation-induced fear. Recently many authors consider social facilitation a basic form of social learning that can explain by more mundane means some phenomena that have been earlier treated in terms of “animal culture” such as milk bottle opening by tits and potato washing by Japanese macaque monkeys. We will consider these and other examples further in this Part.

“ Response facilitation ” is a close but narrower notion than social facilitation. If observation enhances the relative frequency of an act that is already in the repertoire of an animal, it is referred to as response facilitation. This can be illustrated with results of experiments with naï ve animals. For instance, in ground squirrels the presence and behaviour of conspecifics affect juvenile alarm-call responses. Visually isolated juveniles were less likely to respond to play-back alarm calls (Mateo, 1996). Naï ve ants reared in isolation both of socially experienced ants and symbiotic aphids providing them by sweet excretes, display species-specific patterns of aphid tending earlier and more effectively if they gain a possibility to observe experienced aphid tending nestmates (Reznikova and Novgorodova, 1998).

Stimulus enhancement (e.g. Spence, 1937; Galef 1988) is said to have occurred when the presence of an individual draws an observer's attention to a particular object (the “manipulandum”), thus enhancing the observer's opportunity to learn about the object. The result of this narrowing of behavioural focus is that the individual's subsequent behaviour becomes concentrated upon these key variables. Generalised stimulus enhancement focuses the observer’s attention on an object as a whole while localised stimulus enhancement focuses the attention on a functional part of the object only. However, the observer does not copy actions of the demonstrator, and the actual actions of the observer are acquired on the basis of trial and error.

Social facilitation and stimulus enhancement from more experienced individuals can serve as proximal mechanisms fostering safe incorporation of novel foods, spread of knowledge about predators and other dangers, and even increasing effectiveness of mate choice.

Observational conditioning takes place when the demonstrator’s actions provide the observer with the opportunities to learn that the appearance or movement of an object signals the occurrence of an appetitive or aversive event. The observer thus learns the relation between some part of the environment and the reinforcer, that is, a Pavlovian association may be established (Zentall and Levine, 1972; Heyes, 1993). Socially-transmitted food preferences (Galef, 1988) represent a special case of observational conditioning. The mechanisms responsible for socially-acquired food preferences appear to have strong simple associative learning components (e.g., learned safety or the habituation of neophobia to the novel taste), for which the presence of a conspecific may serve as a catalyst. Furthermore, these specialised mechanisms may be unique to foraging and feeding systems.

One of the best examples of observational conditioning is in the acquisition of fear of snakes by laboratory-reared monkeys exposed to a wild-born conspecific in the presence of a snake (Mineka and Cook, 1988). This example was discussed in Part VII. Presumably, a fearful conspecific serves as the unconditioned stimulus, and the snake serves as the conditioned stimulus. It appears that exposure to a fearful conspecific or to a snake alone is insufficient to produce fear of snakes in the observer.

When observation of a demonstrator allows an animal to learn how the environment works, a form of learning is involved which has been labelled “ emulation ” (Tomasello et al., 1987). Whereas stimulus enhancement changes the salience of certain stimuli in the environment, emulation changes the salience of certain goals (Byrne, 2002). In " emulation" the learner gains information from observing a demonstration, but in achieving the same goal, may use a different method. The investigation which prompted the recognition of this process involved chimpanzees learning from a trained conspecific how to rake food items into a cage (Tomasello et al., 1987). The data showed that chimps exposed to the skilled demonstrator learned how to use the rake, unlike controls, who were unsuccessful in the task, despite manipulating the tool just as often. Animals, however, did not copy the precise strategy employed by the trained conspecifics. Instead, the observers were learning from the demonstration the “affordances” of the tool. The meaning of " emulation learning" (Call and Tomasello, 1994) has expanded to incorporate observational learning about the properties of objects and potential relationships among them. Emulation can also account for findings of observation learning that have been earlier treated as imitation.