SOCIAL LEARNING

Social learning refers to the acquisition of social information and behav- ior. It is ostensibly no different from other forms of learning, although historically it has been differentiated from classical and operant conditioning (Bandura & Walters,

1963;

Miller & Dollard, 1941).

A

narrower definition refers to “situations in which one individual comes to behave similarly to others” (Boesch & Tomasello,

1998,

p.

598).

Modem theories of children’s social learning strongly emphasize cogni- tive processes. Albert Bandura

(1986, 1989))

the person most closely associ- ated with the study of social learning, reformulated his theory to reflect cognitive, as opposed to associative-learning, mechanisms underlying chil- dren’s acquisition of social behavior; and the most popular alternative ac- count of children’s social learning (and social cognition in general) is the social information-processing perspective (Crick & Dodge, 1994; Dodge,

1986;

Rubin & Krasnor,

1986),

which proposes that children engage in a series of cognitive processes (encoding, interpretation, searching for and evaluating response alternatives) when engaging in social interaction.

Neither of these approaches has focused on evolutionary issues, al- though much of the research generated from these theories has important implications for evolutionary developmental perspectives. In this section, we examine various ways in

which

juveniles acquire social information and behavior from observing the behavior of others. We take a comparative perspective, focusing on mechanisms of social learning used not just

by

humans but

by

other social primates, as well as aspects of social learning that seem to be unique to Homo sapiens and that may serve as the foundation for more complicated forms of social cognition.

Forms of Social Learning Local Enhancement

One of the simplest forms of social learning is local enhancement (Thorpe, 1956). Animals (including humans) may observe other individuals

engaging in some behavior with a particular object or at a particular location.

Animals may then interact with the same objects or move to the particular location and, as a result, learn some specific behaviors via mechanisms of operant or classical conditioning. Learning has thus occurred mediated

by

observation, but nothing specific has been learned from observing the behav- ior of others. By attending to the actions of conspecifics, animals simply put themselves in a particular place or with particular objects and learn something from the experience.

Mimicry

If

imitation is defined as the replication of an observed behavior, then mimicry qualifies as imitation. However, mimicry refers to the duplication of a behavior without any understanding of the goal of that behavior.

Mimicry is observed in the behavior of some birds who are able to “parrot”

the vocal responses of humans. It is also demonstrated

by

human children.

For example, every time a barely verbal 2-year-old boy enters the grocery store, he steps on the 7-foot scale, looks up at its face, and waits for the needle to settle. His behavior is nearly identical to that of his father, but this child cannot understand the goal of this behavior (to obtain a measure of one’s weight), for he has neither the concept of “one’s weight” nor any idea of what the numbers on the face mean. He is accurately reproducing an observed behavior but does not comprehend the goal of the model.

We do not want to minimize the cognitive abilities that underlie mimicry. An individual must observe a model, store the representation of the behavior in memory, retrieve that representation when the proper environmental cues are present, and then reproduce the behavior. Individu- als who mimic another can acquire complicated behaviors that may produce some positive consequences and thus become part of their behavioral reper- toire, all without the need of understanding the goal of the model.

Emulation

In emulation, one individual observes another interacting with an object to achieve a specific goal. That individual then interacts with the object attempting to attain the same end

but

does not duplicate the same behavior as the model to achieve that goal (Boesch & Tomasello,

1998;

Tomasello,

1996,2000).

For example, one chimpanzee may observe another getting ants from under a log

by

rolling the log. The chimp may then approach the same or a different log with the goal of obtaining ants. However, the second chimp (observer)

will

not duplicate the specific behaviors that it observed but will emit a variety of behaviors on the log, until the log is moved and ants are discovered.

If

successful, the ape will have learned, via trial and error, a valuable behavior, but not by imitation as conventionally

SOCIAL CocNri-roN

I95

understood. It has been suggested that local enhancement and emulation learning are the mechanisms underlying the “cultural transmission” of nut cracking observed in a group of West African chimpanzees (Boesch &

Tomasello,

1998).

The same argument could be made for the cultural trans- mission of termite fishing in other chimpanzee populations (Goodall,

1986).

Imitation

According to some theorists, true imitation requires that an observer be able to take the perspective of the model (Boesch & Tomasello,

1998;

Tomasello, 1996,2000; Tomasello, Kruger,

6r

Ratner,

1993).

It is not enough simply to observe and repeat the target behavior as in mimicry; for true imitation to occur, the imitator must understand the goal that the model had in mind (as in emulation) and reproduce important aspects of that behavior. According to comparative developmental psychologist Michael Tomasello and his colleagues (Tomasello,

1999;

Tomasello et al.,

1993),

this ability is unique to humans. Although social learning is observed in many other primate species, only humans possess cultural learning-the trans- mission of acquired information and behavior within and across generations with a high degree of fidelity. “In cultural learning, learners do not just direct their attention to the location of another individual’s activity; rather, they actually attempt to see a situation the way the other sees it-from inside the other’s perspective, as it were” (Tomasello et al., 1993, p.

496).

(Tomasello’s claim that cultural learning is limited to humans may have to be rethought, given evidence of cultural transmission in wild chimpanzees, some of which we discuss briefly below; see also Whiten et al.,

1999.)

Tomasello et al. proposed three stagelike levels of cultural learning in humans-imitative, instructed, and collaborative-with each stage involv- ing a more advanced form of perspective-taking than the former. (Note that one stage does not replace earlier ones but affords individuals new means of social learning to accompany the earlier mechanisms.)

Imitative Learning. In imitatiwe learning the learner internalizes some- thing of the model’s behavioral strategies and intentions for executing the observed behavior. The learner must understand the model’s goal, which requires the ability to take his or her perspective. According to Tomasello and his colleagues, imitative learning is first seen during the latter part of the first year, when infants begin to imitate language sounds and actions with objects (Abravanel & Gingold,

1985).

Preverbal children engage in imitative learning, as is illustrated by experiments in which toddlers imitate not the precise actions of a model but their intended actions. In a study

by

developmental psychologist Andrew Meltzoff (

1999,

18-month-old infants observed adult models successfully and unsuccessfully execute behaviors on objects. For one task, a model

picked up a dumbbell-shaped object and made definite movements on the wooden-cube ends of the dumbbell, removing one of the cubes (successful condition).

In

the unsuccessful condition, infants watched a model pull on the ends of the dumbbell, but her hand slipped off the cubes, and the dumbbell did not separate. When later given the dumbbell, infants who had seen the successful demonstrations and infants who had seen the unsuccessful demonstrations removed the cube end significantly more often than

did

infants in control conditions. They seemed to realize what the model in the unsuccessful condition intended to do and imitated her behavior to achieve an inferred (but not witnessed) goal. In a second experiment,

14-

and 18-month-old infants watched as either a person or a mechanical device acted on an object (e.g., a person or a vise removed the cube end of a dumbbell ). Infants were twice as likely to imitate the actions when they had witnessed a person versus a machine perform the action, illustrating that

by 14

months of age, infants understand that people (but not inanimate objects) have intentions (goals) that are sometimes worthy of imitating. In other research,

14-

to 18-month-old infants observed adults engage in com- plex behavior sequences, some that appeared “intentional” as reflected

by

the model’s vocal behavior and others that, based on what the models said, were “accidental.” When later given the opportunity to imitate the model, the infants reproduced twice as many intentional as accidental behaviors (Carpenter, Akhtar, & Tomasello, 1998), again suggesting that infants have some understanding of the intentions of adults and will imitate intentional (goal-directed) actions but not accidental ones.

Imitation has been extensively studied in the great apes (see Custance, Whiten, & Bard,

1995;

Galef,

1988;

Parker & McKinney, 1999; Whiten, 1996). Although some convincing evidence exists for immediate imitation of action in sign-language-trained and wild chimpanzees (e.g., signs and facial expressions), less-convincing evidence exists of immediate imitation of actions on objects (Tomasello, Davis-Dasilva, Camak, & Bard,

1987;

Whiten, Custance, Gbmez, Teixidor, & Bard,

1996).

For example, in one study, chimpanzees who were skilled at using a tool to acquire honey (honey fishing) were paired with nai’ve chimpanzees (Hirata & Morimura,

2000).

Three of six naive chimpanzees spontaneously observed their more experi- enced partner obtain honey either before making any attempt themselves or after a failed attempt to obtain honey. These chimpanzees rarely observed the more experienced partners following a successful attempt at honey fishing. These findings suggest that chimpanzees understand, at some level, that observing a more skilled conspecific is a necessary step in social learning.

However, only two of five chimpanzees succeeded in their first attempt following an observation of their successful partner, suggesting that observa- tion, although necessary, is not sufficient for imitation to take place. More- over, having the chance to observe the problem being solved did not acceler-

SOCIAL COGNITION 197

ate the learning process: Chimpanzees paired with an experienced partner took as long to solve the honey-fishing problem as chimpanzees who solved the problem alone (i.e., without the benefit of observing how it is done;

but see Bard, Fragaszy, & Visalberghi,

1995,

for a possible exception). Thus, although tool use in chimpanzees clearly seems to involve social learning (Matsuzawa,

1999),

there is little indication that it involves true imitation.

Yet, it is incontrovertible that chimpanzees are marvelous social learn- ers. Research with both free-living and laboratory animals has consistently shown that chimpanzees acquire complex behaviors, often involving the use of tools, in social contexts (e.g., Boesch,

1991;

Call & Tomasello,

1994;

Goodall,

1986;

McGrew,

1992;

Visalberghi, Fragaszy, & Savage-Rumbaugh, 1995). Recent claims have even been made for chimpanzee culture, with

39

distinct behaviors being identified as culturally transmitted, including fishing for ants and termites, cracking nuts, and grooming (Whiten et al.,

1999).

Results of several recent studies suggest that some aspects of imitative learning may indeed be observed in some chimpanzees to varying degrees.

As we noted in chapter

5,

convincing evidence of deferred imitation of a model’s actions, not attributable to emulation or local enhancement, has been observed only in enculturated apes (Bering et al.,

2000;

Miles et al.,

1996;

Tomasello, Savage-Rumbaugh, & Kruger,

1993).

Although we believe that these studies provide solid evidence of deferred imitation in these animals, it could be argued that the apes were merely mimicking the model’s behavior and

did

not actually understand the model’s intention.

Several studies involving chimpanzees with significant contact with humans have suggested that this was not the case. In one study, four chimpanzees, three with “language-training” experience, saw a human model perform a series of actions to open a box and remove food from it (Whiten, 1998b).

Actions were performed in specified sequences (e.g., open bolt 1, open bolt

2,

rotate pin, turn handle). The apes witnessed three demonstrations before they were first permitted access to the box themselves. After this first trial, the chimpanzees witnessed another demonstration, followed immediately

by

their second attempt to open the box, followed by another demonstration and a third and final attempt. Although two of the chimpanzees opened the box on their first attempt and three on the second attempt, there was no evidence that they matched the action sequence of the model on the first two trials. That is, although they opened the box, they

did

not organize their actions in the same sequence as

did

the model. However, the action sequences of the apes

did

match those of the model to a statistically significant degree for the third trial (in which all four apes opened the box), although they

did

not copy with great fidelity the particular behaviors within those sequences. (It is interesting to note that the single non- language-trained chimpanzee performed the poorest on this task.) Appar- ently, the repeated demonstrations, along with their previous efforts to