Is It What You Do,or When You Do It? The Roles of Contingency and Similarity in Pro‐Social Effects of Imitation

Being imitated has a wide range of pro‐social effects, but it is not clear how these effects are mediated. Naturalistic studies of the effects of being imitated have not established whether pro‐social outcomes are due to the similarity and/or the contingency between the movements performed by the actor and those of the imitator. Similarity is often assumed to be the active ingredient, but we hypothesized that contingency might also be important, as it produces positive affect in infants and can be detected by phylogenetically ancient mechanisms of associative learning. We manipulated similarity and contingency between performed and observed actions in a computerized task. Similarity had no positive effects; however, contingency resulted in greater enjoyment of the task, reported closeness to others, and helping behavior. These results suggest that the pro‐social effects of being imitated may rely on associative mechanisms.     

Motor learning by observation: Evidence from a serial reaction time task

This study sought evidence of observational motor learning, a type of learning in which observation of the skilled performance of another person not only facilitates motor skill acquisition but does so by contributing to the formation of effector-specific motor representations. Previous research has indicated that observation of skilled performance engages cognitive processes similar to those occurring during action execution or physical practice, but has not demonstrated that these include processes involved in effector-specific representation. In two experiments, observer subjects watched the experimenter performing a serial reaction time (SRT) task with a six-item unique sequence before sequence knowledge was assessed by response time and/or free generation measures. The results suggest that: (1) subjects can acquire sequence information by watching another person performing the task (Experiments 1-2); (2) observation results in as much sequence learning as task practice when learning is measured by reaction times (RTs) and more than task practice when sequence learning is measured by free generation performance (Experiment 2, Part 1); and (3) sequence knowledge acquired by model observation can be encoded motorically--that is, in an effector-specific fashion (Experiment 2, Part 2).     

Book reviews

Smith, L. D. (1986). Behaviorism and logical positivism: A reassessment of the alliance. Stanford, CA: Stanford University Press. Pp. ix + 398. ISBN 0-8047-13014. $42.50.

Schusterman, R. J., Thomas, J. A., & Wood, F. G. (Eds.). (1986). Dolphin cognition and behavior: A comparative approach. Hillsdale, NJ: Lawrence Erlbaum Associates, Inc. Pp. xv + 393. ISBN 0-89859-5940. Paperback, £17.00.

Rauschecker, J. P. & Marler, P. (Eds.). (1987). Zmprinting and cortical plasticity: Comparative aspects of sensitive periods. New York: John Wiley & Sons. Pp. 377. ISBN 0-471-84368-7. £57.50.

Walker, S. (1987). Animal learning: An introduction. London: Routledge & Kegan Paul. Pp. 426. ISBN 0-7102-0482-5; hardback, £20.00. ISBN 0-7102-1152-X; paperback, £10.95.

Gray, J. A. (1987). The psychology of fear and stress (second edition). Cambridge: Cambridge University Press. Pp. X+422. ISBN 0521-24958-9 (hardback). £42.50. ISBN 0521-27098-7 (paperback). £1 5.00.     

Book reviews

Montefiore, A. & Noble, D. (Eds.). (1989). Goals, no-goals and own goals: A debate on goal-directed and intentional behaviour. London: Unwin Hyman. Pp. ix + 304. ISBN 0-04-445341-8. £30.00 (hardback).

McNaughton, N. (1989). Biology and emotion. Cambridge: Cambridge University Press. Pp. 228. ISBN 0-521-26527-4. £27.50 (hardback); ISBN 0-521-31938-2. £9.95 (paperback).

Amsel, A. (1989). Behaviorism, neobehaviorism, and cognitivism in learning theory: Historical and contemporary perspectives. Hillsdale, NJ: Lawrence Erlbaum Associates, Inc. Pp. 105. ISBN 0-8058-0332-7. £15.00 (hardback).

Bolles, R. C. & Beecher, M. D. (1988). Evolution and learning. Hillsdale, NJ: Lawrence Erlbaum Associates, Inc. Pp. 263 + xi. ISBN 89589-542-8. £23.95 (hardback).

Davey, Graham (1989). Ecological learning theory. London: Toutledge. Pp. 392 + xv. ISBN 0-415-01190-6. £14.95 (paperback).

Davison, M. & McCarthy, D. (1988). The matching law: A research review. Hillsdale, NJ: Lawrence Erlbaum Associates, Inc. Pp. 285. ISBN 0-90959-923-7. £29.95 (hardback).     

The interaction between response effects during the acquisition of response priming

In three experiments we investigated the role of associative learning in the acquisition of response priming by effect stimuli, by examining their interaction during response-effect learning. Having replicated the ability of visual effect stimuli to prime their associated responses, we paired a response with a compound consisting of visual and auditory effects before assessing the ability of the auditory effect stimulus to prime the response. This priming was reduced if the visual stimulus had been pre-trained as an effect of the response. By contrast, priming by the visual effect stimulus was potentiated when the auditory effect had been pre-trained. We interpret these interactions in terms of contemporary associative learning theory derived from studies of conditioning.     

Infants' behavioral reenactment of "failed attempts": exploring the roles of emulation learning,stimulus enhancement,and understanding of intentions

Two studies were conducted to examine whether infants' reenactment of intended but unconsummated acts in A. N. Meltzoff's (1995) failed-attempt paradigm is due to reading the adult's underlying intention or to the effects of nonimitative social learning processes. Two novel conditions that emphasized the object affordances and the spatial contiguity of the object sets were devised. When infants' first actions only were counted, infants who observed the full-demonstration model produced more target acts. When all target acts produced within the 20-s response period were counted, infants in the emulation-learning and spatial contiguity conditions produced as many target acts as infants in the full-demonstration and failed-attempt conditions. This pattern of findings suggests that nonimitative social learning processes may influence infants' response in the behavioral reenactment paradigm.     

The discrimination of natural movement by budgerigars (Melopsittacus undulates) and pigeons (Columba livia)

Three experiments examined the ability of birds to discriminate between the actions of walking forwards and backwards as demonstrated by video clips of a human walking a dog. Experiment 1 revealed that budgerigars (Melopsittacus undulates) could discriminate between these actions when the demonstrators moved consistently from left to right. Test trials then revealed that the discrimination transferred, without additional training, to clips of the demonstrators moving from right to left. Experiment 2 replicated the findings from Experiment 1 except that the demonstrators walked as if on a treadmill in the center of the display screen. The results from the first 2 experiments were replicated with pigeons in Experiment 3. The results cannot be explained if it is assumed that animals rely on static cues, such as those derived from individual postures, in order to discriminate between the actions of another animal. Instead, this type of discrimination appears to be controlled by dynamic cues derived from changes in the posture of the demonstrators.     

When does social learning become cultural learning?

Developmental research on selective social learning, or ‘social learning strategies’, is currently a rich source of information about when children copy behaviour, and who they prefer to copy. It also has the potential to tell us when and how human social learning becomes cultural learning; i.e. mediated by psychological mechanisms that are specialized, genetically or culturally, to promote cultural inheritance. However, this review article argues that, to realize its potential, research on the development of selective social learning needs more clearly to distinguish functional from mechanistic explanation; to achieve integration with research on attention and learning in adult humans and ‘dumb’ animals; and to recognize that psychological mechanisms can be specialized, not only by genetic evolution, but also by associative learning and cultural evolution.     

Hypothalamo-Pituitary-Adrenocortical Regulation Following Lesions of the Central Nucleus of the Amygdala

Previous reports indicate that the central nucleus of the amygdala (CeA) stimulates adrenocorticotropin and corticosterone secretion, suggesting a role for this region in central hypothalamo-pituitary-adrenocortical (HPA) stress regulation. To evaluate this hypothesis, this study assessed the impact of CeA lesion on the response of hypophysiotrophic paraventricular nucleus (PVN) neurons to acute restraint and chronic unpredictable stress exposure. In contrast to previous reports, CeA lesions did not affect corticosterone or ACTH secretion induced by acute stress. Acute restraint increased PVN corticotropin releasing hormone (CRH) mRNA expression, increased the number of parvocellular PVN neurons expressing the co-secretagogue arginine vasopressin (AVP), and induced cFOS mRNA expression in the parvocellular PVN. However, there was no additional effect of CeA lesion on any measure of PVN activation. Chronic unpredictable stress exposure induced long-term activation of the HPA axis, noted by thymic involution, adrenal hypertrophy and increased PVN CRH mRNA expression. Stress-induced changes in thymus and adrenal weights were not affected by CeA lesion. Further, CeA lesion rats did not differ from controls in post-stress CRH mRNA expression. However, basal CRH mRNA expression was increased in the PVN of CeA rats, suggesting that the CeA plays a role in long-term inhibition of the PVN. The results of these studies are not consistent with the hypothesis that the CeA is necessary for stress-induced pituitary-adrenocortical activation. Rather, this region may play a stressor-specific modulatory role in regulation of HPA function.