Elizabeth Ray

What Is the Significance of Imitation in Animals

Publisher Summary This chapter explains the significance of imitation in animals. The greatest challenge for any theory of the cognitive mechanisms of imitation is to explain imitation of “perceptually opaque” actions, those actions that yield dissimilar sensory inputs when observed and executed. The reason of this difficulty is discussed in the chapter. The chapter also distinguishes two types of theory of imitation, transformational and associative, in terms of the way in which they attempt to meet this challenge. Transformational theories suggest that most of the information necessary to achieve a behavioral match is generated internally by complex cognitive processes, whereas associative theories claim that this information is derived principally from experience. These theories delineate plausible alternative accounts of the psychological mechanisms of imitation, but they do not provide a satisfactory framework for empirical inquiry because each theory either does not make testable predictions or is inconsistent with what is already known about the conditions of imitation. The associative sequence learning (ASL) theory is discussed and the significance of imitation in animals with respect to culture rather than cognition is also discussed.

Imitation in Infancy: The Wealth of the Stimulus.

Imitation requires the imitator to solve the correspondence problem--to translate visual information from modelled action into matching motor output. It has been widely accepted for some 30 years that the correspondence problem is solved by a specialized, innate cognitive mechanism. This is the conclusion of a poverty of the stimulus argument, realized in the active intermodal matching model of imitation, which assumes that human neonates can imitate a range of body movements. An alternative, wealth of the stimulus argument, embodied in the associative sequence learning model of imitation, proposes that the correspondence problem is solved by sensorimotor learning, and that the experience necessary for this kind of learning is provided by the sociocultural environment during human development. In a detailed and wide-ranging review of research on imitation and imitation-relevant behaviour in infancy and beyond, we find substantially more evidence in favour of the wealth argument than of the poverty argument.

Goal attribution to schematic animals: do 6-month-olds perceive biological motion as animate?

Infants are sensitive to biological motion, but do they recognize it as animate? As a first step towards answering this question, two experiments investigated whether 6-month-olds selectively attribute goals to shapes moving like animals. We habituated infants to a square moving towards one of two targets. When target locations were switched, infants reacted more to movement towards a new goal than a new location - but only if the square moved non-rigidly and rhythmically, in a schematic version of bio-mechanical movement older observers describe as animal-like (Michotte, 1963). Goal attribution was specific to schematic animal motion: It did not occur if the square moved rigidly with the same rhythm as the animate stimulus, or if the square had the same amount of non-rigid deformation, but in an inanimate configuration. The data would seem to show that perception of schematic animal motion is linked to a system for psychological reasoning from infancy. This in turn suggests that 6-month-olds may already interpret biological motion as animate.

Spatial S-R compatibility effects in an intentional imitation task.

The active intermodal mapping hypothesis suggests that intentional imitation is mediated by a highly efficient, special-purpose mechanism of actor-centered movement encoding. In the present study, using methods from stimulus-response (S-R) compatibility research, we found no evidence to support this hypothesis. In two experiments, the performance of adult participants instructed to imitate actorcentered spatial properties of head, arm, and leg movements was affected by task-irrelevant, egocentric spatial cues. In Experiment 1, participants imitated using the same side of their bodies as did the model, and performance was less accurate when egocentric stimulus location was response incompatible than when it was response compatible. This effect was reversed in Experiment 2 when participants imitated using the opposite side of their bodies. These findings, in line with general process theories of imitation, imply that intentional imitation is mediated by the same processes that mediate responding to inanimate stimuli on the basis of arbitrary S-R mappings.

Emerging perception of causality in action-and-reaction sequences from 4 to 6 months of age: is it domain-specific?

Two experiments (N=136) studied how 4- to 6-month-olds perceive a simple schematic event, seen as goal-directed action and reaction from 3 years of age. In our causal reaction event, a red square moved toward a blue square, stopping prior to contact. Blue began to move away before red stopped, so that both briefly moved simultaneously at a distance. Primarily, our study sought to determine from what age infants see the causal structure of this reaction event. In addition, we looked at whether this causal percept depends on an animate style of motion and whether it correlates with tasks assessing goal perception and goal-directed action. Infants saw either causal reactions or noncausal delayed control events in which blue started some time after red stopped. These events involved squares that moved either rigidly or nonrigidly in an apparently animate manner. After habituation to one of the four events, infants were tested on reversal of the habituation event. Spatiotemporal features reversed for all events, but causal roles changed only in reversed reactions. The 6-month-olds dishabituated significantly more to reversal of causal reaction events than to noncausal delay events, whereas younger infants reacted similarly to reversal of both. Thus, perceptual causality for reaction events emerges by 6 months of age, a younger age than previously reported but, crucially, the same age at which perceptual causality for launch events has emerged in prior research. On our second question, animate/inanimate motion had no effect at any age, nor did significant correlations emerge with our additional tasks assessing goal perception or goal-directed object retrieval. Available evidence, here and elsewhere, is as compatible with a view that infants initially see A affecting B, without differentiation into physical or psychological causality, as with the standard assumption of distinct physical/psychological causal perception.

Imitation of lateralised body movements: Doing it the hard way

Two experiments examined imitation of lateralised body movement sequences presented at six viewing angles (0°, 60°, 120°, 180°, 240°, and 300° rotation relative to the participants body). Experiment 1 found that, when participants were instructed simply to “do what the model does”, at all viewing angles they produced more actions using the same side of the body as the model (anatomical matches), than actions using the opposite side (anatomical non-matches). In Experiment 2 participants were instructed to produce either anatomical matches or anatomical non-matches of observed actions. When the model was viewed from behind (0°), the anatomically matching group were more accurate than the anatomically non-matching group, but the non-matching group was superior when the model faced the participant (180° and 240°). No reliable differences were observed between groups at 60°, 120°, and 300°. In combination, the results of Experiments 1 and 2 suggest that, when they are confronting a model, people choose to imitate the hard way; they attempt to match observed actions anatomically, in spite of the fact that anatomical matching is more subject to error than anatomical non-matching.