Experimental studies of learning and the higher mental processes in infra-human primates.

Evolution of Primate Cognition

“…In principle, this knowledge can be gained without individual experimentation, by means of social learning, and the long periods of dependency of monkeys and especially apes have been seen as potential "apprenticeships" enabling acquisition of skills for dealing with physical problems (Bruner, 1972;Parker, 1996). Social enhancement of learning is well known in many species (Galef, 1988;Spence, 1937), whereas the direct acquisition of others' knowledge by imitation has been difficult to establish even among great apes, and is apparently absent in monkeys and strepsirhines. However, the recent evidence that suggests that great apes can imitate the "program level" of organization of complex behavior, understanding hierarchical organization and thus constructing novel plans partly by observation, raises a new problem: how did the ability to mentally represent the organization of complex behavior evolve?…”

Imitative Choice Behavior in Guppies

“…One is to investigate whether or not the subjects can easily solve the problem after they are given a series of opportunities to observe another animal's solution of the same problem (Watson, 1908;Kohler, 1917;Warden & Jackson, 1935). Spence (1937) presented, however, a critical review of this method and contended that the movements of parts of the apparatus by the demonstrator, and the appearance of food when the animal succeeds, may enhance the stimulus value of that part of the apparatus and hence make the imitator more likely to respond to it.…”

When actions are carved at the joints

“…They describe stimulus enhancement as if it were an associative phenomenon, in which a conditioned stimulus (CS; e.g., a location) acquires excitatory strength as a result of being observed in conjunction with an unconditioned stimulus (US; e.g., a conspecific eating). This is odd because, ever since Spence (1937) coined the term stimulus enhancement, it has been treated as a variety of single stimulus learning in which conspecific behaviour draws the observer's attention to a stimulus, but does not act as a reinforcer. Observational conditioning (Mineka et al 1984) is the term traditionally used for learning that is thought to depend on socially mediated exposure to a CS-US relationship.…”

“…The great majority of observations that suggest nonhuman imitation are vulnerable to reinterpretation as stimulus enhancement coupled with individual learning (Spence 1937;"local enhancement," Thorpe 1956). Stimulus enhancement is the tendency to pay attention to, or aim responses towards, a particular place or objects in the environment after observing a conspecific's actions at that place or in conjunction with those objects.…”