An analysis of generalized imitation

An experimenter presented English words to three intermediate-level children and reinforced accurate imitation of these words. The experimenter also presented novel Spanish words, but the imitation of these words was never experimentally reinforced. One subject quickly ceased performing non-reinforced imitative responses. The other two subjects were exposed to a series of conditions designed to facilitate discrimination. Upon observing the first subject for one session they immediately ceased imitating Spanish demonstrations. For all three subjects, when reinforcement was delivered for responses other than imitation, all imitative responses eventually ceased. When reinforcement was reintroduced for English imitations there was an immediate resumption of such responses to their previous 100% level. The occurrence of non-reinforced imitations in this and previous studies was discussed as being a function of one or combination of four variables: (1) similarity acquiring conditioned reinforcing properties, or (2) instructional, (3) coincidental, or (4) conditional stimulus generalization.     

The effects of a discriminative cue and an incompatible activity on generalized imitation

Four noncompliant retardates were observed in a generalized imitation study. Two variables were studied: provision of a competing reinforced activity, and use of a cue to aid discrimination between reinforced and nonreinforced imitations. Both variables were found to increase the rate of discrimination between the two sets of stimuli. Greatest discrimination occurred when both cue and alternative task were present. Discrimination decreased when the variables were removed. Results are interpreted as implying that imitation of nonreinforced cues in generalized imitation procedures varies with the degree to which reinforcement is available for other activity, as well as with the complexity of the discrimination problem. These results help indicate conditions under which the generalized imitation effect may be observed in more naturalistic settings.     

Development of syntax in a retarded girl using procedures of imitation, reinforcement, and modelling

Three experiments demonstrated the development and generalized use of a singular and plural declarative sentence in a child initially lacking sentence form responses. In each experiment, an adult(s) served as a language model(s), and consequences (sweets) were provided for imitation of the model. During training trials, an item(s) was displayed first to the model(s) then to the subject; these displays were accompanied by requests to label the item(s). Generalization was assessed by a number of probe trials that were periodically interspersed among training trials. During these trials, the subject was requested to label the displayed item(s) without any preceding labelling response from the model. Using these procedures, generalized use of a singular sentence ("That is one-") resulted in Experiment I, and generalized use of a plural sentence ("These are two-") resulted in Experiment II. In Experiment III, two models (a singular and a plural sentence model) were made available to the subject but imitation of only one model was reinforced during any one condition. Results indicated the subject labelled probe (generalization) items with the same sentence form that was modelled and reinforced during training trials.     

Some experiments on the organization of a class of imitative behaviors

A retarded child was taught to imitate diverse demonstrations made by an experimenter, until new demonstrations were imitated correctly upon first presentation without direct training. These imitations could be maintained without reinforcement, when they were distributed among other reinforced imitations. Factors responsible for the continued performance of these unreinforced imitations were examined. When subjected to massed extinction trials, unreinforced imitations eventually disappeared; they reappeared when again interspersed among reinforced imitations. In addition, the stimulus function of "similarity of response between subject and experimenter" was examined. The subject was taught a set of non-imitative responses, through discriminative stimuli controlled by the experimenter, and a comparable imitative set. Unreinforced non-imitations, like reinforced imitations, were maintained only when interspersed among reinforced imitations. When all reinforcement was discontinued, all responses extinguished similarly, indicating that reinforcement was necessary to maintain the response-class organization, but not confirming an essential role for "similarity" as such.     

Generalized imitative affection: Relationship to prior kinds of imitation training

Two experiments utilizing first- and second-grade Canadian children showed that generalized imitative physical affection was most facilitated by prior imitative physical contact training (as opposed to verbal contact training) when the object of the affection was either a toy teddy bear, Experiment I, or an adult human, Experiment II.Additional findings from Experiment I showed that generalized imitative physical aggression was equally facilitated by imitative physical contact training and that punishment, as well as extinction operations applied to training imitations, resulted in suppression of all generalized imitations with no differential effect of punishment on affection or aggression being noted.The lack of any persisting imitations in a control group in Experiment II, which received noncontingent reinforcement but instructional prompting for training imitations, suggested that instructional control of imitation responses was initially weak and that the contingency between reinforcement and training imitations was critical for continued occurrence of training imitations and any occurrence of generalized physical affection imitations.     

A variable influencing the performance of generalized imitative behaviors

This research attempted to demonstrate some of the conditions that would influence the performance of generalized imitative behaviors in young children. Two experiments were conducted. The results of Exp. I indicated that generalized imitative behaviors can be very durable; only one of three subjects was influenced by a variety of reinforcement-like procedures. Control over the behavior of all three subjects was obtained when a setting event involving the presence or absence of the experimenter was systematically varied. A second test of this variable was carried out in Exp. II. Results showed moderate to strong control over non-reinforced imitations in four preschool children.     

An experimental analysis of verbal imitation in preschool children

A model presented English words to three preschool children and reinforced accurate imitation of these words. The model also presented novel Russian words but the subjects' imitation of these words was never reinforced. As long as the subjects' imitation of English words was reinforced, their accuracy of imitating non-reinforced Russian words increased. When reinforcement was not contingent upon imitation of English words, accuracy of imitating both the English and the Russian words decreased. These results support and extend previous work on imitation.     

Behavioral similarity as a reinforcer for preschool children

Three experiments evaluated whether behavioral similarity provided by an adult could serve as a reinforcer for the modelling behavior of four preschoolers. In each experiment, sessions consisted of two kinds of trials: (1) experimenter-modelled trials, when the child's imitation of modelled motor responses was reinforced with praise and tokens, and (2) child-modelled trials when experimenter imitation of child-modelled responses was contingent upon the child's modelling one of three alternative responses: operation of a ball, horn, or clicker. Experiment I showed that the children consistently modelled whichever responses the experimenter imitated. Experiment II determined whether that performance was due to differences in the amount of experimenter behavior following imitated versus nonimitated child models or to experimenter imitation. Neither reducing nor increasing the amount of experimenter behavior following the children's nonimitated models altered their modelling of imitated responses. Experiment III evaluated whether experimenter imitation of child models was a reinforcer because the child's imitative responses were reinforced on experimenter-modelled trials. In Experiment III, the children's nonimitation of experimenter-models was reinforced with praise and tokens on a schedule of differential reinforcement of other behavior, yet they continued to model experimenter-imitated responses on child-modelled trials. These results indicate behavioral similarity was reinforcing, though no conditioning history through which it acquired that function was demonstrated.     

The development of imitation by reinforcing behavioral similarity to a model

This research demonstrated some of the conditions under which retarded children can be taught to imitate the actions of adults. Before the experiment, the subjects were without spontaneous imitative behavior, either vocal or motor. Each subject was taught, with food as reinforcement, a series of responses identical to responses demonstrated by an experimenter; i.e., each response was reinforced only if it was identical to a prior demonstration by an experimenter. Initially, intensive shaping was required to establish matching responses by the subjects. In the course of acquiring a variety of such responses, the subjects' probability of immediate imitation of each new demonstration, before direct training, greatly increased. Later in the study, certain new imitations, even though perfect, were never reinforced; yet as long as some imitative responses were reinforced, all remained at high strength. This imitativeness was then used to establish initial verbal repertoires in two subjects.     

DO INFANTS SHOW GENERALIZED IMITATION OF GESTURES? II. THE EFFECTS OF SKILLS TRAINING AND MULTIPLE EXEMPLAR MATCHING TRAINING

The determinants of generalized imitation of manual gestures were investigated in 1‐ to 2‐year‐old infants. Eleven infants were first trained eight baseline matching relations; then, four novel gestures that the infants did not match in probe trials were selected as target behaviors. Next, in a generalized imitation test in which matching responses to baseline models were intermittently reinforced, but matching responses to target models were not eligible for reinforcement, the infants matched baseline models but not the majority of their target behaviors. To ensure their failure to match the target behaviors was not due to motor constraints, the infants were trained, in a multiple‐baseline procedure, to produce the target responses under stimulus control that did not include an antecedent model of the target behavior. There was no evidence of generalized imitation in subsequent tests. When the infants were next trained to match each target behavior to criterion (tested in extinction) in a multiple‐baseline‐across‐behaviors procedure, only 2 infants continued to match all their targets in subsequent tests; the remaining infants matched only some of them. Seven infants were next given mixed matching training with the target behaviors to criterion (tested in extinction); they subsequently matched these targets without reinforcement when interspersed with trials on which matching responses to baseline models were intermittently reinforced. In repeat tests, administered at 3‐week intervals, these 7 children (and 2 that did not take part in mixed matching training) continued to match most of their target behaviors. The results support a trained matching account, but provide no evidence of generalized imitation, in 1‐ to 2‐year‐old infants.     

Stimulus control of generalized imitation in subnormal children

Generalized imitation was established in three young subnormal children by reinforcing their imitations of a limited set of modeled actions in the presence of a large ball. A discrimination was then established by training nonimitation in the presence of a small ball. Imitation was then tested for various other ball sizes. Rate of imitation decreased as the test stimuli increasingly differed in size from the large ball. Imitations that were never reinforced occurred at about the same rate as those that were reinforced when in the presence of the large ball in training.     

Mothers' and infants' responses to their partners' spontaneous action and vocal/verbal imitation

Twenty mother-infant dyads (10 boys, 10 girls) were videotaped longitudinally at ages 10, 13, 17, and 21 months during in-home free play and bath sessions. Mothers' and infants' responses to their partners' naturally occurring action and vocal/verbal imitations were described, and relations to infants' imitation rates and vocabularies were examined. Mothers' response rates were consistently high and unrelated to infants' imitation rates. As early as 10 months, infants responded to the great majority of maternal imitations, especially action imitations, often with actions. Infants' return imitations to action matching indicated increasing awareness of being imitated. Infants' responses to mothers' vocal/verbal imitation were associated with their later vocabulary levels. Children who would be more lexically advanced at 17 and/or 21 months provided more social responses at 10 months, more socially responsive actions and return verbal imitations at 13 months, and more non-imitative socially responsive words at 17 and 21 months.     

GENERALIZED IMITATION AND RESPONSE-CLASS FORMATION IN CHILDREN WITH AUTISM

An experimental analysis of imitation was conducted to examine the influence of response topography on generalization of imitation across three response types. Four children with autism were presented with both reinforced training trials and nonreinforced probe trials of models from vocal, toy-play, and pantomime response types. The probe trials were used to examine generalization within each response type. A multiple baseline design was used to analyze percentage of matching and nonmatching responses to models across response types. This study, the first to analyze imitative response classes in children with autism, showed that imitation generalized from reinforced training models to nonreinforced probe models within a response type, but it did not generalize across response types. Thus, functional response classes determined by topographical boundaries were exhibited within generalized imitation.     

Continued Longitudinal Rorschach Study of a Child for Years Three to Five

The present study was designed to assess whether induced behavioral similarity is reinforcing and, if so, whether it leads to increased subsequent imitation, or whether the increased imitation is a function of the predictability of the observer's responses. Sixty Dutch school age boys and girls participated. The experiment consisted of a modeling-only condition and three (i.e., contingent, noncontingent, and consistent) imitation conditions. All conditions consisted of 15 or less induction trials and 18 modeling trials. Except for the consistent imitation condition, none of the conditions allowed perfect predictability of the observer's responses during induction trials. The results revealed that the contingent imitation of the children's target response did not cause them to demonstrate that response more often and that it did not lead to increased imitations on subsequent modeling trials. By contrast, increased imitation was observed for the one condition suggesting perfect predictability of the observer's imitations.     

DO INFANTS SHOW GENERALIZED IMITATION OF GESTURES?

Two experiments were conducted to investigate generalized imitation of manual gestures in 1- to 2-year-old infants. In Experiment 1, 6 infants were first trained four baseline matching relations (e.g., when instructed "Do this", to raise their arms after they saw the experimenter do so). Next, four novel gestures that the infants did not match in probe trials were selected as target behaviors during generalized imitation Test 1; models of these gestures were presented on unreinforced matching trials interspersed with intermittently reinforced baseline matching trials. None of the infants matched the target behaviors. To ensure that these behaviors were in the infants' motor skills repertoires, the infants were next trained to produce them, at least once, under stimulus control that did not include an antecedent model of the target behavior. In repeat generalized imitation trials (Test 2), the infants again failed to match the target behaviors. Five infants (3 from Experiment 1) participated in Experiment 2, which was identical to Experiment 1 except that, following generalized imitation Test 1, the motor-skills training was implemented to a higher criterion (21 responses per target behavior), and in a multiple-baseline, across-target-behaviors procedure. In the final generalized imitation test, 1 infant matched one, and another infant matched two target behaviors; the remaining 17 target behaviors still were not matched. The results did not provide convincing evidence of generalized imitation, even though baseline matching was well maintained and the target behaviors were in the infants' motor skills repertoires, raising the question of what are the conditions that reliably give rise to generalized imitation.     

An experimental demonstration of discriminated (nongeneralized) imitation

In a number of experiments, nonreinforced imitation has been found to persist at high rates despite the variety of procedures which have been employed to eliminate such responses. In the present experiment, powerful stimulus control was established over imitation by providing an alternative response which was reinforcible. Four children participated in a multiple-schedule experiment in which imitation was reinforced in the presence of one light and bar pressing in the presence of a second light; throughout the experiment, responses were modeled on each trial: hand-arm responses in the presence of the red light and leg responses in the presence of the yellow light. Initially, imitation was reinforced in the presence of the red light and button pressing in the presence of the yellow light. In a within-subjects design, stimulus control was demonstrated by reversing the association of lights and contingencies, then reinstating the original contingencies. The children imitated when reinforced for imitation and pressed the button when button pressing was reinforced. The results demonstrate stimulus control over imitation which is more powerful than in previous investigations and indicate that the prevailing reinforcement contingencies determine whether or not a child will imitate on a particular occasion.This research was supported by a Faculty Summer Research Grant from The American University. The authors wish to express their appreciation to the School for Contemporary Education, McLean, Virginia, and to Dr. Sally Sibley, Mr. David Williams, and Mrs. Linda Trout for their cooperation in providing subjects and research space.     

Learning to imitate individual finger movements by the human neonate

Imitation in human neonates, unlike imitation in young infants, is still regarded as controversial. Four studies with 203 newborns are presented to examine the imitation of index finger, two‐ and three‐finger movements in human neonates. Results found differential imitations of all three modelled gestures, a left‐handed pattern, and a rapid learning mechanism. The lateralized behavioural pattern suggests the involvement of a right lateralized neural network, and the mechanisms described in this study – (i) the accurate imitation of all aspects of the model's movements, (ii) the rapid learning component, and the (iii) the early sensitive period might fulfil the criteria for filial imprinting.     

The effect of incongruent instructions and consequences on imitation in retarded children

Three retarded boys served as subjects in a 13-phase experiment. In eight of these phases, the instructions administered by the experimenter before demonstrating a behavior and the consequences for imitative behavior were incongruent (the consequences were not those indicated by the instructions). Consequences rather than instructions controlled imitative behavior when (a) subjects were instructed not to imitate but received reinforcers if they imitated; (b) subjects were instructed to imitate but were differentially reinforced for other behavior; (c) subjects were instructed to imitate but were verbally reprimanded for imitation. Although subjects were highly imitative at the beginning of the study, when there was no reinforcement for imitation subjects gradually stopped imitating when instructed not to imitate. Instructions seemed to control imitative behavior when there was no reinforcement for imitation and subjects were instructed to imitate. These results indicated a need for further investigation of antecedent and consequent variables in imitation experiments and pointed out that certain techniques may be more efficient than others in eliminating well-established responses.     

THE DEVELOPMENT AND GENERALIZATION OF DELAYED IMITATION1

An individual's behavior can be identified as imitative if it temporally follows the behavior of another individual and if its topography is controlled by the demonstrated behavior [Baer, Peterson, and Sherman (Journal of the Experimental Analysis of Behavior, 1967, 10 , 405–416)]. This definition takes into account both temporal and topographical characteristics of the behavior in question. More recent research in the area of imitation has interpreted the temporal component of the above definition differentially by limiting imitation to those topographically similar responses occurring within 3, 5, or 10 sec after a model's demonstration. Yet, Gewirtz and Stingle (Psychological Review, 1968, 75 , 375–397) pointed out that much of the imitation seen in young children is not of this immediate nature, but instead occurs sometime after a model's response. They further suggest that this type of imitative behavior can be characterized as a response class and is susceptible to development and modification as a function of consequences delivered to subjects contingent on this type of delayed responding. Four retarded children, three initially imitative and one nonimitative, were individually trained to imitate a number of motor responses in an immediate and a delayed fashion. Immediate imitation was defined as a response similar to a model's demonstration occurring within 5 sec after the model's demonstration; delayed imitation was defined as a response similar to a model's demonstration occurring more than 5 sec, but not more than 25 sec, after the model's demonstration. A reversal (ABAB) design was employed to examine the experimental development of a generalized delayed imitative repertoire. Untrained probe responses were demonstrated to subjects systematically through the ongoing training. Generalized immediate and delayed imitation were observed in each subject; this generalization was restricted to the type of imitation currently undergoing training. This development of a generalized imitation repertoire was observed in each subject. That is, these subjects imitated some responses that had never been specifically trained. More importantly, a training package consisting of prompting, fading, and consequences for delayed imitation functioned to develop generalized delayed imitation. These data exemplify a special case of generalization that was a function of the most recent training history of immediate or delayed imitation. The reversal design demonstrated that imitations of nontrained models were either delayed or immediate, depending upon which form of imitation was currently receiving training. Therefore, for each form of imitation trained, delayed or immediate, a corresponding response class was demonstrated. These data relate to data reported by Garcia, Baer, and Firestone (Journal of Applied Behavior Analysis, 1971, 4 , 101–112). The association lies in the proposition that there are identifiable boundaries of generalized imitation and that these boundaries are functionally related to previous training histories.     

Cardiac and respiratory conditioning, differentiation, and extinction in the pigeon

Paired light and foot shock in 12 pigeons rapidly developed acceleratory heart and respiratory conditioned responses. Sensitization and stimulus control birds did not condition. When a different colored stimulus light that was not reinforced was mixed in a random series with the reinforced light, rapid differentiation of both heart and respiratory responses occurred. In most cases neither heart nor respiratory conditioned responses could be extinguished by 100 non-reinforced presentations of the conditioned stimulus.