Hélène Cochet

Pointing gestures produced by toddlers from 15 to 30 months: different functions, hand shapes and laterality patterns.

Three experimental designs were implemented in day nurseries in order to elicit imperative, declarative expressive, and declarative informative pointing gestures (Tomasello, Carpenter, & Liszkowski, 2007) among a population of 48 toddlers aged 15-30 months. Several features were recorded for each situation, including gesture form, gaze direction, and vocalizations. A unimanual reaching task was also administered, in order to compare laterality patterns for each type of gesture. Main results revealed that imperative gestures were associated with whole-hand pointing, whereas declarative gestures were more frequently characterized by an extended index finger. Moreover, declarative gestures were more frequently accompanied by vocalizations than imperative gestures were. Finally, different degrees of manual preference were observed, especially for informative pointing gestures, which tended to be more right-handed than reaching actions. Results of the study are discussed in relation to the nature and development of each kind of pointing gesture.

Hand preference for pointing gestures and bimanual manipulation around the vocabulary spurt period

This study investigated the development of hand preference for bimanual manipulative activities and pointing gestures in toddlers observed longitudinally over a 5-month period, in relation to language acquisition. The lexical spurt was found to be accompanied by an increase in the right-sided bias for pointing but not for manipulation. Moreover, results revealed a significant correlation between hand preference for imperative pointing gestures and manipulative activities in children who did not experience the lexical spurt during the observational period. By contrast, measures of handedness for declarative pointing were never correlated with those of handedness for manipulation. This study illustrates the complex relationship between handedness and language development and emphasizes the need to take the different functions of pointing gestures into account.

Evolutionary origins of human handedness: evaluating contrasting hypotheses

Variation in methods and measures, resulting in past dispute over the existence of population handedness in nonhuman great apes, has impeded progress into the origins of human right-handedness and how it relates to the human hallmark of language. Pooling evidence from behavioral studies, neuroimaging and neuroanatomy, we evaluate data on manual and cerebral laterality in humans and other apes engaged in a range of manipulative tasks and in gestural communication. A simplistic human/animal partition is no longer tenable, and we review four (nonexclusive) possible drivers for the origin of population-level right-handedness: skilled manipulative activity, as in tool use; communicative gestures; organizational complexity of action, in particular hierarchical structure; and the role of intentionality in goal-directed action. Fully testing these hypotheses will require developmental and evolutionary evidence as well as modern neuroimaging data.

Development of hand preference for object-directed actions and pointing gestures: A longitudinal study between 15 and 25 months of age

The development of hand preferences for object-directed actions and pointing gestures was investigated in toddlers sampled bimonthly between 15 and 25 months of age. Language level was also assessed, in an attempt to examine the relationship between handedness and language development. Results did not reveal any changes over the study period in the mean Handedness Index of the whole sample, both for bimanual manipulative activities and pointing gestures. However, the categorization of participants as left-handers, right-handers, or non-lateralized revealed that most of children presented nonlinear individual trajectories in the development of hand preference. Moreover, the only significant correlations observed between hand preferences for manipulation and pointing were negative correlations between the strength of hand preferences at 19 and 21 months of age, suggesting that manipulative actions and communicative gestures are controlled by different networks in the left cerebral hemisphere. These findings are discussed in relation to the development of speech-gesture links in infancy.

Hand preferences in human adults: non-communicative actions versus communicative gestures.

Hand preferences for pointing gestures and bimanual manipulative activities were investigated in 127 adult participants. Pointing gestures were produced in two different conditions: a speech condition, in which the gestures were accompanied by speech, and a silent condition. Although the classification of participants as left- or right-handers, or ambidextrous, was consistent across the manipulation and pointing tasks for 85% of participants, results showed only moderate correlations between handedness scores for bimanual manipulation and pointing gestures. Moreover, results did not reveal any difference in the degree of hand preference between pointing gestures produced along with speech and gestures produced on their own. The implications of these findings are discussed in relation to the lateralization of non-communicative manual actions, communicative gestures and speech.

Morphological differences between imperative and declarative pointing: hand shape, arm extension, and body posture.

ABSTRACT. The authors used frame-by-frame video analyses to describe the features of imperative and declarative pointing gestures produced by young children, in comparison to reaching actions. First, the results showed that imperative pointing shared common features with reaching actions (hand shape, arm extension), but body posture observed in reaching differed from the one observed in pointing, both in imperative and declarative contexts. Second, hand shape was influenced by precision constraints: imperative gestures shifted from whole-hand pointing to index-finger pointing when the target was surrounded by distractors. This study is the first of its kind to highlight the effect of several variables on morphological features of pointing using quantitative measures and may provide insights into the nature of imperative and declarative pointing.

Hand preference for pointing and language development in toddlers

The aim of this study was to investigate the relationship between hand preference for communicative gestures and language during development. Hand preference for pointing gestures and level of language were assessed in 46 toddlers between 12 and 30 months of age. Results showed a right-hand preference for pointing and the use of a developmental quotient (DQ) for language revealed a significant correlation between the degree of hand preference and DQ for language in children with a quotient above 100. Thus, these children were more right-handed for pointing gestures as DQ increased. These results highlight the close association between the development of hand preference for pointing and the speed of language development, suggesting a new direction for studies of language-gesture links in toddlers.

Manual asymmetries and hemispheric specialization: Insight from developmental studies

The objective of this review is to obtain a better understanding of the relationship between manual asymmetries and hemispheric specialization by focusing on the development of hand preference and cerebral lateralization of language. We first sought to describe the development of manual asymmetries for different activities (i.e., grasping and manipulating objects vs. communicating through gestures), and the development of cerebral asymmetries, before examining available data on the association between hand preference and HS for language. We also analyzed behavioral studies on the relation between hand preference and language development, as well as more specific studies on the relation between the cerebral control of gestures and language. Finally, we aimed at providing a wider view on functional asymmetries by emphasizing the need to study hemispheric specialization for functions other than language, and in particular for visual attention.

Communication in the second and third year of life: Relationships between nonverbal social skills and language

We aimed to investigate developmental continuities between a range of early social and communicative abilities (including gestural communication) and language acquisition in children aged between 11 and 41 months. Initiation of joint attention and imitation were strongly correlated to language comprehension and production. Moreover, the analysis of different communicative gestures revealed significant relationships between language development and the production of symbolic gestures, declarative pointing (declarative informative pointing in particular), and head nodding. Other gestures such as imperative pointing, showing, and head shaking were not found to correlate with language level. Our results also suggest that distinct processes are involved in the development of language comprehension and production, and highlight the importance of considering various characteristics of childrens early communicative skills.

Where have all the (ape) gestures gone

Comparative analysis of the gestural communication of our nearest animal relatives, the great apes, implies that humans should have the biological potential to produce and understand 60–70 gestures, by virtue of shared common descent. These gestures are used intentionally in apes to convey separate requests, rather than as referential items in syntactically structured signals. At present, no such legacy of shared gesture has been described in humans. We suggest that the fate of “ape gestures” in modern human communication is relevant to the debate regarding the evolution of language through a possible intermediate stage of gestural protolanguage.