Relationship between manual preferences for object manipulation and pointing gestures in infants and toddlers

The aim of this study was to measure the pattern of hand preferences for pointing gestures as a function of object‐manipulation handedness in 123 infants and toddlers (10–40 months). The results showed that not only right‐handers but also left‐handers and ambidextrous participants tended to use their right hand for pointing. There was a significant correlation between manual preferences and pointing lateralization. Further analyses showed that the correlation between these two indexes was at its strongest during two key phases of language development (i.e. vocabulary spurt and syntax improvement) and weakened to become nonsignificant in the interim. These findings support the view that humans have a specialized area for communicative gestures and language in the left cerebral hemisphere that may be independent of the system controlling the purely motor functions of hand use.     

Object-related knowledge and the production of gestures with imagined objects by preschool children

Previous research suggests that the gestural representation of preschool age children has a symbolic quality in the absence of real objects. It has shown a developmental progression from use of concrete body parts to more abstract imaginary-object gestural representations during the preschool years. The present study examined whether object-related knowledge is involved in the production of imaginary-object gestures. 35 children (12 3-, 11 4-, and 12 5-yr.-olds) performed gestural tasks in which they were asked to pretend to use common objects, e.g., "pretend to brush your teeth with a toothbrush." In addition, they were asked to describe the relationship between the performed gesture and object when they were pretending. Analysis indicated that, when an imaginary-object gesture was performed, it was through an evoked prior knowledge of the function and context of the use of objects. This may suggest that object-related knowledge is a key factor involved in developmental changes from body part to imaginary-object gestures and that it is involved in freeing preschool children from object substitution, which is prescribed by perceptual support.     

Infants' knowledge of objects: beyond object files and object tracking

Two independent research communities have produced large bodies of data concerning object representations: the community concerned with the infant's object concept and the community concerned with adult object-based attention. We marshal evidence in support of the hypothesis that both communities have been studying the same natural kind. The discovery that the object representations of young infants are the same as the object files of mid-level visual cognition has implications for both fields.     

Speech-associated gestures, Broca's area, and the human mirror system

Speech-associated gestures are hand and arm movements that not only convey semantic information to listeners but are themselves actions. Broca's area has been assumed to play an important role both in semantic retrieval or selection (as part of a language comprehension system) and in action recognition (as part of a "mirror" or "observation-execution matching" system). We asked whether the role that Broca's area plays in processing speech-associated gestures is consistent with the semantic retrieval/selection account (predicting relatively weak interactions between Broca's area and other cortical areas because the meaningful information that speech-associated gestures convey reduces semantic ambiguity and thus reduces the need for semantic retrieval/selection) or the action recognition account (predicting strong interactions between Broca's area and other cortical areas because speech-associated gestures are goal-direct actions that are "mirrored"). We compared the functional connectivity of Broca's area with other cortical areas when participants listened to stories while watching meaningful speech-associated gestures, speech-irrelevant self-grooming hand movements, or no hand movements. A network analysis of neuroimaging data showed that interactions involving Broca's area and other cortical areas were weakest when spoken language was accompanied by meaningful speech-associated gestures, and strongest when spoken language was accompanied by self-grooming hand movements or by no hand movements at all. Results are discussed with respect to the role that the human mirror system plays in processing speech-associated movements.     

A note on temporal relations between language and gestures

The initiation of the spontaneous gestures of Wernicke's aphasics was analyzed in relation to shifts in semantic content between the syntactic boundaries of main clauses and embedded clauses. Gestures proved more likely to arise at the initial boundaries of embedded clauses when these were semantically discontinuous with the main clause than when these were semantically related to the main clause. Spontaneous gestures may signal underlying shifts in semantic intention, thereby reflecting the difficulties encountered by Wernicke's aphasics in maintaining a coherent stream of thought across syntactic boundaries.     

婴儿指示性手势与其语言学习的关系

指示性手势是指明空间中某个物体、处所或事件的手部动作,在婴儿1岁时出现,与婴儿的语言学习存在着较强的相关,然而目前尚不清楚为什么会存在此相关。可能存在两种内在机制:(1)指示性手势影响婴儿的学习环境——引发了适时的语言输入;(2)影响学习者本身——帮助婴儿创造有效的学习状态并示意给他人。未来的研究需要探讨这两种机制如何交互作用,以及如何将指示性手势作为诊断或干预工具,用于识别和帮助有语言障碍风险的个体。     

Spoken language and arm gestures are controlled by the same motor control system

Arm movements can influence language comprehension much as semantics can influence arm movement planning. Arm movement itself can be used as a linguistic signal. We reviewed neurophysiological and behavioural evidence that manual gestures and vocal language share the same control system. Studies of primate premotor cortex and, in particular, of the so-called "mirror system", including humans, suggest the existence of a dual hand/mouth motor command system involved in ingestion activities. This may be the platform on which a combined manual and vocal communication system was constructed. In humans, speech is typically accompanied by manual gesture, speech production itself is influenced by executing or observing transitive hand actions, and manual actions play an important role in the development of speech, from the babbling stage onwards. Behavioural data also show reciprocal influence between word and symbolic gestures. Neuroimaging and repetitive transcranial magnetic stimulation (rTMS) data suggest that the system governing both speech and gesture is located in Broca's area. In general, the presented data support the hypothesis that the hand motor-control system is involved in higher order cognition.     

Gesturing and naming: the use of functional knowledge in object identification

Studies using functional imaging show reliable activation of premotor cortex when observers view manipulable objects. This result has led to the view that knowledge of object function, particularly the actions associated with the typical use of objects, may play a causal role in object identification. To obtain relevant evidence regarding this causal role, we asked subjects to learn gesture-color associations and then attempt to identify objects presented in colors denoting functional gestures that were congruent or incongruent with the objects' use. A strong congruency effect was observed when subjects gestured the use of an object, but not when they named an object. We conclude that our procedure constitutes a sensitive measure of the recruitment and causal role of functional knowledge and that this recruitment is not present during object naming. Preliminary evidence, however, indicates that gestures evoked by the volumetric shape of an object do contribute to object naming.     

Looking and search measures of object knowledge in preschool children

The same preschoolers were tested on an observation task and a search task involving the invisible displacement of an object. In the observation task, children watched an object roll behind a screen from which protruded the top of a solid wall. Analyses revealed significantly longer looking to impossible than to possible outcomes in all children. In search, the child was allowed to retrieve the rolled object. Most 3-year-olds but significantly fewer 2.5-year-olds completed the search successfully. An unexpected sex difference was found, with boys outperforming girls. Search performance was not associated with observation measures. The findings indicate that children visually discriminate violations of solidity but that this sensitivity is not associated with successful search performance.     

Domains and knowledge effects: strategies in object and social classification

This research examined differences in classification strategies in object and social domains. Wattenmaker (1995) found that additive classification rules were more compatible with the social than the object domain. The present experiments examined the generality of these results by using fundamentally different types of social and object categories. A sorting paradigm was used to evaluate the frequency with which subjects used additive strategies. In Experiment 1, the social domain was represented by social events that possess very different properties than core social concepts such as traits or occupations. Even with these types of social materials, however, many more additive strategies and family resemblance sorts occurred with social than object materials. In Experiment 2, the object domain was represented by abstract object categories that were designed to possess properties of core social concepts such as traits. Again, however, more additive strategies and family resemblance sorts occurred with social than object materials. The results indicate that differences in the compatibility between additive strategies and object and social domains are not limited to subsets of categories in these domains but rather extend to many types of object and social categories.     

Relationship between gender and knowledge of U.S. state names and locations

Two experiments were conducted to assess gender differences in knowledge of U.S. state names and locations. Subjects for both experiments were drawn from a population that was approximately 95% Caucasian, 2% Native American, 1% Black, 1% Asian, and 1% Hispanic. Experiment 1 demonstrated superior male performance with respect to ability to correctly label state outlines on a blank map. Providing subjects with a list of state names (as a recall aid) resulted in performance deficits that were of equivalent magnitude for both males and females. It is suggested that this may have changed subjects' labeling strategy. Experiment 2, which assessed ability to list state names, showed no gender differences and no effect for providing a blank map (as a recall aid). Therefore, the performance differences obtained in Experiment 1 appear mediated by a gender difference in geographical knowledge and not by a gender difference in knowledge of state names. Implications of geographical knowledge deficits are briefly discussed.     

Embodying gestures: The Social Orienting Model and the study of early gestures in autism

Autistic spectrum disorders impair the ability to interact socially. Detecting and understanding their onset is not only an empirical enterprise, but also a theoretical one, often linked to studies on intersubjectivity. Different theoretical perspectives have been elaborated in the past to account for the deficit. The main purpose of this paper is to reinforce and offer empirical grounding to a recent approach, termed Social Orienting Model, by presenting the main theoretical approaches to autism and contrasting them to this view, as well as considering its possible effect on empirical research, focusing on current literature analyzing gestures in children with autism.

Speech-associated gestures, Broca’s area, and the human mirror system

Speech-associated gestures are hand and arm movements that not only convey semantic information to listeners but are themselves actions. Broca’s area has been assumed to play an important role both in semantic retrieval or selection (as part of a language comprehension system) and in action recognition (as part of a “mirror” or “observation–execution matching” system). We asked whether the role that Broca’s area plays in processing speech-associated gestures is consistent with the semantic retrieval/selection account (predicting relatively weak interactions between Broca’s area and other cortical areas because the meaningful information that speech-associated gestures convey reduces semantic ambiguity and thus reduces the need for semantic retrieval/selection) or the action recognition account (predicting strong interactions between Broca’s area and other cortical areas because speech-associated gestures are goal-direct actions that are “mirrored”). We compared the functional connectivity of Broca’s area with other cortical areas when participants listened to stories while watching meaningful speech-associated gestures, speech-irrelevant self-grooming hand movements, or no hand movements. A network analysis of neuroimaging data showed that interactions involving Broca’s area and other cortical areas were weakest when spoken language was accompanied by meaningful speech-associated gestures, and strongest when spoken language was accompanied by self-grooming hand movements or by no hand movements at all. Results are discussed with respect to the role that the human mirror system plays in processing speech-associated movements.     

Expertise increases the functional overlap between face and object perception

Recent studies indicate that expertise with objects can interfere with face processing. Although competition occurs between faces and objects of expertise, it remains unclear whether this reflects an expertise-specific bottleneck or the fact that objects of expertise grab attention and thereby consume more central resources. We investigated the perceptual costs of expertise by measuring visual thresholds for identifying targets embedded within RSVP sequences presented at varying temporal rates. Car experts and novices searched for face targets among face and car distractors, or watch targets among watch and car distractors. Remarkably, car experts were slower than novices at identifying faces among task-irrelevant cars, yet faster than novices at identifying watches among cars. This suggests that car expertise leads to greater functional overlap between cars and faces while reducing the functional overlap between cars and objects, a result incompatible with the notion of an encapsulated module for exclusive processing of faces.     

On the relation between object manipulation and stereotypic self-injurious behavior

Results from a number of studies have shown an inverse relationship between stereotypic behavior and object manipulation. The purposes of this study were to determine whether techniques similar to those used previously (prompting and reinforcement) would be effective in increasing object manipulation under both prompted and unprompted conditions, and to ascertain whether increases in object manipulation would result in decreases in stereotypic self-injurious behavior (SIB). Two individuals with developmental disabilities who engaged in SIB maintained by automatic reinforcement participated. Results showed that object manipulation increased from baseline levels when experimenters prompted participants to manipulate leisure items, but that object manipulation was not maintained under unprompted conditions, and rates of SIB stayed within baseline levels. We then attempted to increase object manipulation further by (a) reinforcing object manipulation, (b) blocking SIB while reinforcing manipulation, and (c) preventing SIB by applying protective equipment while reinforcing object manipulation. Reinforcing object manipulation alone did not affect levels of object manipulation. Blocking effectively reduced attempts to engage in SIB for 1 participant but produced no increase in object manipulation. When the 2nd participant was prevented from engaging in SIB through the use of protective equipment, rates of object manipulation increased dramatically but were not maintained when the equipment was removed. These results suggest that stimulation derived from object manipulation, even when supplemented with arbitrary reinforcement, may not compete with stimulation produced by stereotypic SIB; therefore, direct interventions to reduce SIB are required.     

The influence of surface color information and color knowledge information in object recognition

In order to clarify whether the influence of color knowledge information in object recognition depends on the presence of the appropriate surface color, we designed a name-object verification task. The relationship between color and shape information provided by the name and by the object photo was manipulated in order to assess color interference independently of shape interference. We tested three different versions for each object: typically colored, black and white, and nontypically colored. The response times on the nonmatching trials were used to measure the interference between the name and the photo. We predicted that the more similar the name and the photo are, the longer it would take to respond. Overall, the color similarity effect disappeared in the black-and-white and nontypical color conditions, suggesting that the influence of color knowledge on object recognition depends on the presence of the appropriate surface color information.     

Difference between highlight and object colors enhances glossiness

The effect of highlight and object colors on perception of glossiness was examined. Ten participants rated glossiness of object images. The color coordinates of objects and highlights were varied while luminance of each pixel was unchanged. Four colors were used for objects and highlights. Objects were perceived as glossier when the highlight color was different from the object color than when they were the same. Objects with some unnatural combinations of highlight and object colors were perceived to be as glossy as those with natural color combinations. The results suggested that differences between highlight and object colors enhance perceived glossiness and that perceived glossiness does not depend on naturalness of color combination for highlights and objects.     

The relationship between object files and conscious perception

Object files (OFs) are hypothesized mid-level representations which mediate our conscious perception of persisting objects-e.g. telling us 'which went where'. Despite the appeal of the OF framework, not previous research has directly explored whether OFs do indeed correspond to conscious percepts. Here we present at least one case wherein conscious percepts of 'which went where' in dynamic ambiguous displays diverge from the analogous correspondence computed by the OF system. Observers viewed a 'bouncing/streaming' display in which two identical objects moved such that they could have either bounced off or streamed past each other. We measured two dependent variables: (1) an explicit report of perceived bouncing or streaming; and (2) an implicit 'object-specific preview benefit' (OSPB), wherein a 'preview' of information on a specific object speeds the recognition of that information at a later point when it appears again on the same object (compared to when it reappears on a different object), beyond display-wide priming. When the displays were manipulated such that observers had a strong bias to perceive streaming (on over 95% of the trials), there was nevertheless a strong OSPB in the opposite direction-such that the object files appeared to have 'bounced' even though the percept 'streamed'. Given that OSPBs have been taken as a hallmark of the operation of object files, the five experiments reported here suggest that in at least some specialized (and perhaps ecologically invalid) cases, conscious percepts of 'which went where' in dynamic ambiguous displays can diverge from the mapping computed by the object-file system.