Imitation Paradigm Research Articles

Computational prosodic markers for autism

We present results obtained with new instrumental methods for the acoustic analysis of prosody to evaluate prosody production by children with Autism Spectrum Disorder (ASD) and Typical Development (TD). Two tasks elicit focal stress — one in a vocal imitation paradigm, the other in a picture-description paradigm; a third task also uses a vocal imitation paradigm, and requires repeating stress patterns of two-syllable nonsense words. The instrumental methods differentiated significantly between the ASD and TD groups in all but the focal stress imitation task. The methods also showed smaller differences in the two vocal imitation tasks than in the picture-description task, as was predicted. In fact, in the nonsense word stress repetition task, the instrumental methods showed better performance for the ASD group. The methods also revealed that the acoustic features that predict auditory-perceptual judgment are not the same as those that differentiate between groups. Specifically, a key difference between the groups appears to be a difference in the balance between the various prosodic cues, such as pitch, amplitude, and duration, and not necessarily a difference in the strength or clarity with which prosodic contrasts are expressed.

Computational prosodic markers for autism

We present results obtained with new instrumental methods for the acoustic analysis of prosody to evaluate prosody production by children with Autism Spectrum Disorder (ASD) and Typical Development (TD). Two tasks elicit focal stress - one in a vocal imitation paradigm, the other in a picture-description paradigm; a third task also uses a vocal imitation paradigm, and requires repeating stress patterns of two-syllable nonsense words. The instrumental methods differentiated significantly between the ASD and TD groups in all but the focal stress imitation task. The methods also showed smaller differences in the two vocal imitation tasks than in the picture-description task, as was predicted. In fact, in the nonsense word stress repetition task, the instrumental methods showed better performance for the ASD group. The methods also revealed that the acoustic features that predict auditory-perceptual judgment are not the same as those that differentiate between groups. Specifically, a key difference between the groups appears to be a difference in the balance between the various prosodic cues, such as pitch, amplitude, and duration, and not necessarily a difference in the strength or clarity with which prosodic contrasts are expressed.

Verbal imitation is based on intention understanding

Using an elicited imitation paradigm, we investigated whether young children imitate the communicative intentions behind speech. Previous research using elicited imitation has shown that children tend to correct ungrammatical sentences. This finding is usually interpreted as evidence that children, like adults, remember and reproduce the gist of linguistic information. In three studies, we tested whether this tendency is also a product of their intention understanding. Replicating and extending previous research by Meltzoff [Meltzoff A. N. (1995). Understanding the intentions of others: Re-enactment of intended acts by 18-month-old children. Developmental Psychology, 31, 838–850], our first two experiments showed that children tend to correct ungrammatical sentences. A critical third experiment showed that children correct ungrammatical sentences only when they believe the model to be an intentional agent. These results complement previous findings from the action domain and strongly support the claim that imitation is based on understanding the intentions of others.

Imitation and the development of infant learning, memory, and categorisation

The ability to copy the actions of others is present from birth in both infant humans and chimpanzees and provides a method for the social transmission of knowledge. For this type of learning to have an impact over the long-term, the infant must be able to encode, store, and retrieve the information they receive for use at a later date. Here we review the literature with the deferred imitation paradigm to demonstrate that by at least 6 months of age, human infants are capable of these comparatively advanced cognitive abilities, which are thought to involve the declarative memory system and the hippocampal formation. Across early development there are dramatic changes in the duration over which information can be retained and the ability of infants to retrieve and express their memories in a flexible manner, which enables them to solve new problems. Research with the deferred imitation paradigm therefore provides important insight into our understanding of social and cognitive development as well as brain development.

The Effect of Learning Experiences and Context on Infant Imitation and Generalization

Over the first years of life, infants gradually develop the ability to retrieve their memories across cue and contextual changes. Whereas maturational factors drive some of these developments in memory ability, experiences occurring within the learning event may also impact infants' ability to retrieve memories in new situations. In 2 experiments we examined whether it was possible to facilitate 12‐month‐old infants' generalization of learning in the deferred imitation paradigm by varying experiences before or during the demonstration session, or during the retention interval. In Experiment 1, altering the length, timing, or variability of training had no impact on generalization; infants showed a low, but consistent level of memory retrieval. In Experiment 2, infants who experienced a unique context for encoding and retrieval exhibited generalization; infants who experienced the context prior to the demonstration session, or during the retention interval, did not. Specificity is a robust feature of infant memory and is not substantially altered by encoding experiences in an observational learning paradigm. Previous history with a learning environment can, however, impact the flexibility of memory retrieval.

Intact automatic imitation of human and robot actions in autism spectrum disorders

The existence of a specialized imitation module in humans is hotly debated. Studies suggesting a specific imitation impairment in individuals with autism spectrum disorders (ASD) support a modular view. However, the voluntary imitation tasks used in these studies (which require socio-cognitive abilities in addition to imitation for successful performance) cannot support claims of a specific impairment. Accordingly, an automatic imitation paradigm (a 'cleaner' measure of imitative ability) was used to assess the imitative ability of 16 adults with ASD and 16 non-autistic matched control participants. Participants performed a prespecified hand action in response to observed hand actions performed either by a human or a robotic hand. On compatible trials the stimulus and response actions matched, while on incompatible trials the two actions did not match. Replicating previous findings, the Control group showed an automatic imitation effect: responses on compatible trials were faster than those on incompatible trials. This effect was greater when responses were made to human than to robotic actions ('animacy bias'). The ASD group also showed an automatic imitation effect and a larger animacy bias than the Control group. We discuss these findings with reference to the literature on imitation in ASD and theories of imitation.

Explicit memory performance in infants of diabetic mothers at 1 year of age

The aim of the present research was to investigate the impact of abnormal fetal environment on explicit memory performance. Based on animal models, it was hypothesized that infants of diabetic mothers (IDMs) experience perturbations in memory performance due to exposure to multiple neurologic risk factors including: chronic hypoxia, hyperglycemia/reactive hypoglycemia, and iron deficiency. Memory performance, as measured by the elicited/deferred imitation paradigm, was compared between 13 IDMs (seven females, six males; mean age 365 days, SD 11) and 16 typically developing children (seven females, nine males; mean age 379 days, SD 9). The IDM group was characterized by shorter gestational age (mean 38w, SD 2), greater standardized birth weight scores (mean 3797g, SD 947), and lower iron stores (mean ferritin concentration 87μ/L, SD 68) in comparison with the control group (mean gestational age: 40w, SD 1; mean birthweight: 3639g, SD 348; mean newborn ferritin concentration 140μg/L, SD 46). After statistically controlling for both gestational age and global cognitive abilities, IDMs demonstrated a deficit in the ability to recall multi-step event sequences after a delay was imposed. These findings highlight the importance of the prenatal environment on subsequent mnemonic behavior and suggest a connection between metabolic abnormalities during the prenatal period, development of memory, circuitry, and behavioral mnemonic performance.

Crawling is associated with more flexible memory retrieval by 9‐month‐old infants

In the present experiment, we used a deferred imitation paradigm to explore the effect of crawling on memory retrieval by 9-month-old human infants. Infants observed an experimenter demonstrate a single target action with a novel object and their ability to reproduce that action was assessed after a 24-hr delay. Some infants were tested with the demonstration stimulus in the demonstration context and some infants were tested with a different stimulus in a different context. Half of the infants in each test condition were crawling at the time of participation and half were not. Both crawling and non-crawling infants exhibited retention when tested with the demonstration stimulus in the demonstration context, but only infants who were crawling by 9 months of age exhibited retention when tested with a different stimulus in a different context. These findings demonstrate that the onset of independent locomotion is associated with more flexible memory retrieval during the first year of life.

Retrieval order variation in a deferred imitation task: Assessment of item-relational information processing among infants.

Item-Specific and Item-Relational Information Processing of Memory Material The interest in imitation for pure and applied research is so great because of its fundamental importance to basic processes in the process of socialization and cognitive development (i.e. language and development in particular). In terms of pure research, imitation paradigms provide researchers with an invaluable, nonverbal tool to explore the process of remembering over time or what is referred to as memory development starting from 6-months of age. With clinical populations imitation serves both a diagnostic and therapeutic function. For example, using an imitation procedure Baer, Petersen, & Sherman. (1967) successfully established a large repertoire of new behaviors among severely to profoundly retarded children ages 9- through 12 years, who had previously displayed no imitative behavior. Subsequent to this the established readiness to imitate was utilized to create initial verbal repertoires in two of the subjects. The study by Baer et al. (1967) demonstrates, on the one hand, that imitation is an extremely effective learning mechanism even for special clinical populations based merely on an appropriate demonstration by a model. On the other hand, the study by Baer et al. (1967) points out nicely that an established predisposition to imitate behaviors can generalize to a new task. Whereas the study by Baer et al. (1967) demonstrates a generalization in the children's readiness to imitate in a new situation, another aspect of generalization with regard to the transfer of learned behaviors acquired through observation of a model to a new context has been of great interest in recent years in part because the flexibility of behavior learned in an imitation paradigm in one context to a new one is one hallmark characteristic of (Eichenbaum & Cohen, 2001). Thus, maintenance and generalization of learning is critical to what is cognitively referred to as declarative memory. Baddeley (1982) distinguished two types of context. Intrinsic context determines the mechanism of how a target item is encoded, so that changing the context during testing requires subjects to recognize something very different from what they originally encoded. An example of intrinsic context might be the sentence in which a target word was presented or the scene in which an image appears. Extrinsic context does not influence how a target item is encoded, but includes aspects of the background such as where the item was learned. Virtually all research with deferred imitation has focused on changes in extrinsic context including changes in testing location, location appearance, or social context (Hanna & Meltzoff, 1993; Learmonth, Lamberth, & Rovee-Collier, 2005; 2006). Only recently has there been research involving a manipulation of intrinsic context with a deferred imitation task, namely the alteration of retrieval order in order to study the specificity of infants' for the organization of test items in a sequence of modeled actions (Knopf, Kraus, & Kressley-Mba, 2006). Memory researchers have long been interested in how retention is affected by the organization of to-be-remembered materials. Organization refers to the specific relations among the elements embodied in a configuration (Puff, 1978). Such relations can be characterized by serial input position, for example, or by a meaningful relation between to-be-remembered items (Puff, 1978; Tulving, 1983). Hunt and Einstein (1981) suggest that at the cognitive level of understanding two types of information processing can be differentiated by the extent to which common features shared by separate events are encoded, namely item relational and item-specific processing. Hunt and Einstein (1981) describe relational information processing as the abstraction of relational information shared by the elements or events at input. …

A comparison of between- and within-subjects imitation designs

Two experimental methods, which have dominated the study of declarative memory in preverbal children with imitation tasks, namely the deferred imitation and elicited imitation paradigm, differ in the amount of physical contact with test stimuli afforded infants prior to a test for long-term recall. The current study assessed effects of pre- and post-demonstration contact with test stimuli on deferred imitation of novel, single-step unrelated actions with multiple objects by 8½- and 10½-month-old infants ( N = 50). The rate of target action completion after a delay remained consistent at both ages across different conditions of prior contact with test stimuli. This study shows that a within-subjects baseline appraisal is valid within certain experimental parameters and offers a more economical alternative. The results show furthermore that different experimental designs utilized to assess deferred imitation are highly comparable for the first year despite differences in determining baseline.

Testing the Agreement/Tense Omission Model using an elicited imitation paradigm

The present study used an elicited imitation paradigm to test the prediction of Schutze & Wexler's (1996) AGREEMENT/TENSE OMISSION MODEL (ATOM) that the rate of non-nominative subjects with agreement-marked verb forms will be sufficiently low that such errors can reasonably be disregarded as noise in the data. A screening procedure identified five children who produced non-nominative subject errors (all her for she) who were then asked to repeat 24 sentences with 3sg feminine pronoun subjects (she) and agreeing main verbs or auxiliaries. All five children produced at least one non-nominative subject (her) with an agreement-marked verb form, and for none of these five children was the non-NOM + AGR rate significantly different to the rate that would be expected by chance, given the independent frequencies of non-nominative subjects and agreement-marked verb forms in their data. The three children for whom this expected (by chance) error rate was significantly greater than 10% (representing an acceptable level of noise in the data) produced non-NOM+AGR errors at a rate significantly greater than 10%, counter to the prediction of the ATOM. These results replicate and extend the naturalistic-data findings of Pine et al. using a different method. They also provide support for the use of elicited imitation as a methodology for assessing children's early grammatical knowledge.

From imitation to creation: the critical yet uncertain transition for Chinese firms

PurposeThis paper aims to consolidate prior research from policy and management domains to identify stages in China's technological learning within the imitation paradigm during 1949‐2001, focusing on changes in the government's strategic priorities and policies and the nature, mode and sources of technological learning, then to contrast the firm and institutional features that have emerged under the imitation paradigm with those defining the emerging creation paradigm. The analysis leads to clear implications for both policy and management for the Chinese firms to make this transition and compete in higher value‐added global industries.Design/methodology/approachAn overview and conceptual paper based on observations and literature review.FindingsThis paper derives a parsimonious set of four dimensions to demarcate five stages in the evolution of China's technological learning: the government's strategic priority, nature of technology, the mode and the source of learning. It identifies six factors acting as significant impediments to Chinese firms' transition from imitation to creation.Originality/valueIn the first place, this paper provides managerial implications which are of great interest to Chinese practicing managers to manage their firms' transition from imitation to creation; second, the policy imperatives highlighted by this paper will help Chinese policymakers to design appropriate incentive mechanisms to enable Chinese firms to build up their competitiveness within the creation paradigm and thereby become global competitors. Meanwhile, this paper provides a systematic analysis on the evolution of China's technology development. This five stage‐based framework will help practicing managers in China understand whether, which and when Chinese firms can make the transition necessary to compete based on the creation of proprietary resources and capabilities.

Imitating versus non-imitating movements: Differences in frontal electroencephalographic oscillatory activity

Non phase-locked oscillatory changes were studied in seven healthy volunteers during two different reaction time movement paradigms, in which the stimulus was a wrist movement (either extension or flexion) performed by another person seated in front of the subject (examiner). In the first paradigm (imitation), the subject was instructed to perform the same movement observed. In the second paradigm (non-imitation), the subject was instructed to perform the opposite movement (flexion when an extension was observed, and vice-versa). Changes in the 7–37 Hz range band were determined by means of Gabor transforms. A frontal energy increase (event-related synchronization, ERS) around 15 Hz could be observed in the frontal region after the examiner's movement; this frontal ERS was significantly larger in the non-imitation paradigm. A typical alpha and beta movement-related event-related desynchronization/synchronization (ERD/ERS) pattern was also observed in both paradigms in the central region. The beta-ERD was significantly larger in the imitation paradigm. Our results show that the motor preparation mechanisms involved in an imitated and a non-imitated movement are different.

Exploring memory in infancy: deferred imitation and the development of declarative memory

Imitation is an important means by which infants learn new behaviours. When infants do not have the opportunity to immediately reproduce observed actions, they may form a memory representation of the event which can guide their behaviour when a similar situation is encountered again. Imitation procedures can, therefore, provide insight into infant memory. The deferred imitation paradigm requires a modelled action to be reproduced following a delay, without prior motor practice. As such, deferred imitation procedures have been proposed to tap declarative memory abilities in non-verbal populations such as infants. Contrary to the popular belief that infants form sparse or ill-defined memories, deferred imitation research reveals that infants store and retrieve highly detailed memory representations. The specificity of detail encoded into the representation can, however, cause memory retrieval to fail at young ages. Developing the ability to identify event components which are central (the target stimulus) versus details which are peripheral (the exact context in which learning occurred) is therefore an important aspect of memory development. Using deferred imitation procedures to study the transition from constrained to flexible memory representations can thus facilitate our understanding of the development of declarative memory during the infancy period. Copyright © 2006 John Wiley & Sons, Ltd.

Exploration or imitation? The effect of music on 4-week-old infants’ tongue protrusions

In a newborn imitation paradigm, an auditory stimulus – music – replaced the standard adult behavioral model. Alternating intervals of music and silence affected 4-week-old infants’ rates of tongue protruding—evidence that tongue protruding is a general response to interesting distal stimuli.

The interaction between specificity and linguistic contrast

Previous studies have shown listeners’ ability to remember fine phonetic details [e.g., Mullennix et al., 1989], providing support for the episodic view of speech perception. The imitation paradigm [Goldinger, 1998, Shockley et al., 2004], in which subjects’ speech is compared before and after they are exposed to target speech (= study phase) has shown that subjects shift their production in the direction of the target. Our earlier results [Nielsen, 2005] showed that the imitation effect for extended VOT was generalized to new stimuli as well as to a new segment, suggesting that the locus of the imitation effect can be smaller than individual words or segments. The current study aims to further investigate how experienced speech input interacts with linguistic representations, by testing whether the imitation effect is observed when the modeled stimuli have reduced VOT (which could introduce linguistic ambiguity). In other words, do speakers imitate and generalize shorter VOT even if the change might impair linguistic contrasts? To address this question, the study phase includes words with initial /p/ with reduced VOT, while the pre- and post-study production list includes (1) the modeled words, (2) the modeled segments /p/ in new words, and (3) the new segment /k/.

Age-related changes in deferred imitation between 6 and 9 months of age

Six- and 9-month-old human infants were tested in a deferred imitation paradigm in which an experimenter performed a single action with a novel object. Although infants of both ages imitated the action when tested immediately, only the 9-month-olds exhibited imitation after a 24-h delay.

Explicit memory performance in infants of diabetic mothers at 1 year of age

The aim of the present research was to investigate the impact of abnormal fetal environment on explicit memory performance. Based on animal models, it was hypothesized that infants of diabetic mothers (IDMs) experience perturbations in memory performance due to exposure to multiple neurologic risk factors including: chronic hypoxia, hyperglycemia/reactive hypoglycemia, and iron deficiency. Memory performance, as measured by the elicited/deferred imitation paradigm, was compared between 13 IDMs (seven females, six males; mean age 365 days, SD 11) and 16 typically developing children (seven females, nine males; mean age 379 days, SD 9). The IDM group was characterized by shorter gestational age (mean 38w, SD 2), greater standardized birthweight scores (mean 3797g, SD 947), and lower iron stores (mean ferritin concentration 87C microg/L, SD 68) in comparison with the control group (mean gestational age: 40w, SD 1; mean birthweight: 3639g, SD 348; mean newborn ferritin concentration 140 microg/L, SD 46). After statistically controlling for both gestational age and global cognitive abilities, IDMs demonstrated a deficit in the ability to recall multi-step event sequences after a delay was imposed. These findings highlight the importance of the prenatal environment on subsequent mnemonic behavior and suggest a connection between metabolic abnormalities during the prenatal period, development of memory, circuitry, and behavioral mnemonic performance.

Generalization of the imitation effect within a natural class

A natural class refers to a set of segments which share acoustic or articulatory features. Support for this notion has traditionally been provided by phonological alternations and phonotactic constraints, and recently by experiments (e.g., Goldrick, 2004). This study investigates the psychological reality of natural class using the imitation paradigm (Goldinger, 1998) in which subjects speech is compared before and after they are exposed to target speech (= study phase). Although this paradigm has shown that subjects shift their production in the direction of the target, these results do not reveal the size of the linguistic unit(s) influenced by the effect. That is, when a subject shifts production of a particular sound in a word, it is uncertain whether the subject is picking up on the word, the segment, or the feature. In this study, to investigate whether phonetic imitation is generalized across members of a natural class, the study-phase word list includes words with initial /p/ and /t/ (with extended VOT), while the pre- and post-study production list includes (1) the modeled words, replicating Shockley et al. (2004), (2) the modeled segments /p/ and /t/ in new words, and (3) the modeled feature [+spread glottis] (aspiration) in a new segment /k/.

Are “late-signing” deaf children “mindblind”? Understanding goal directedness in imitation

Recent studies with “late-signing” deaf children (deaf children born into families in which no-one uses a sign language) have indicated that they have difficulty performing tasks that require them to reason about other people's false beliefs. However, virtually no research has so far investigated how far late signers’ difficulties with mental state understanding extend. This paper reports one study that uses an imitation paradigm to examine whether late signers may also have difficulty in interpreting other people's actions in terms of their goals. Both late-signing ( N = 15) and second generation “native-signing” deaf children ( N = 19) produced a pattern of responses to this task that indicates that they can and readily do view the actions of others as goal-directed. We conclude that this form of mental state understanding (generally seen as a precursor to understanding false beliefs) is intact in late-signing deaf children.