Iconic gesture-speech integration is a relatively recent field of investigation with numerous researchers studying its various aspects. The results obtained are just as diverse. The definition of iconic gestures is often overlooked in the interpretations of results. Furthermore, while most behavioral studies have demonstrated an advantage of bimodal presentation, brain activity studies show a diversity of results regarding the brain regions involved in the processing of this integration. Clinical studies also yield mixed results, some suggesting parallel processing channels, others a (...) unique and integrated channel. This review aims to draw attention to the methodological variations in research on iconic gesture-speech integration and how they impact conclusions regarding the underlying phenomena. It will also attempt to draw together the findings from other relevant research and suggest potential areas for further investigation in order to better understand processes at play during speech integration process. (shrink)

Speakers often use gesture to demonstrate how to perform actions—for example, they might show how to open the top of a jar by making a twisting motion above the jar. Yet it is unclear whether listeners learn as much from seeing such gestures as they learn from seeing actions that physically change the position of objects (i.e., actually opening the jar). Here, we examined participants' implicit and explicit understanding about a series of movements that demonstrated how to move a set (...) of objects. The movements were either shown with actions that physically relocated each object or with gestures that represented the relocation without touching the objects. Further, the end location that was indicated for each object covaried with whether the object was grasped with one or two hands. We found that memory for the end location of each object was better after seeing the physical relocation of the objects, that is, after seeing action, than after seeing gesture, regardless of whether speech was absent (Experiment 1) or present (Experiment 2). However, gesture and action built similar implicit understanding of how a particular handgrasp corresponded with a particular end location. Although gestures miss the benefit of showing the end state of objects that have been acted upon, the data show that gestures are as good as action in building knowledge of how to perform an action. (shrink)

Actions are usually generalized among social group members. Importantly, the efficiency of an action with respect to achieving an external target determines action understanding, and it may have different degrees of social relevance to social groups. Thus, this study explored the role of action efficiency in action generalization. We used computer animations to simulate actions in social groups initiated by visual action cues or category labels, and we measured differences in response times between identifying actions that were and were not (...) consistent with group members, without explicit requirements regarding generalization. It was found that in both visually introduced and explicitly labeled social groups, when the group members acted inefficiently toward the external object, perceivers identified group‐consistent actions faster than group‐inconsistent actions, indicating that the exemplars' common inefficient actions are generalized to the unknown ingroup member, accordingly facilitating the identification of expected consistent inefficient action (Experiment 1). As this effect was not present when removing social group cues, it was determined to be specific to social groups (Experiment 2). Importantly, such generalization was not observed when the identical action was deemed efficient toward the external object (Experiment 3) and was specific to the demonstration of the action being completed by multiple group members rather than being repeated twice by one group member, supporting the group‐based inference and ruling out the possibility of the increased memorability of inefficient actions leading to more generalization relative to efficient actions (Experiment 4). Therefore, the efficiency of an action bounds the generalization of the action across social group members through a process that is spontaneous and implicit. This constrained action generalization may be due to inefficient actions being represented as culture‐specific conventional forms. (shrink)

This study provides new longitudinal evidence on two major types of gesture–speech combination that play different roles in children’s early language. We analysed the spontaneous production of 10 Italian children observed monthly from 10–12 to 23–25 months of age. We evaluated the extent to which the developmental trends observed in children’s early gesture–word and word–word productions can predict subsequent verbal abilities. The results indicate that “complementary” and “supplementary” gesture–speech combinations predict subsequent language development in a different manner: While the onset (...) of “supplementary” combinations predicts the onset of two-word combinations, the use of “complementary” combinations at 12 and 18 months predicts the vocabulary and the ability to produce more words utterances at 2 years of age. Moreover, the results suggest that both “complementary” and “supplementary” crossmodal combinations are good predictive indexes of early verbal skills during the second year of age. (shrink)

This study provides new longitudinal evidence on two major types of gesture–speech combination that play different roles in children’s early language. We analysed the spontaneous production of 10 Italian children observed monthly from 10–12 to 23–25 months of age. We evaluated the extent to which the developmental trends observed in children’s early gesture–word and word–word productions can predict subsequent verbal abilities. The results indicate that “complementary” and “supplementary” gesture–speech combinations predict subsequent language development in a different manner: While the onset (...) of “supplementary” combinations predicts the onset of two-word combinations, the use of “complementary” combinations at 12 and 18 months predicts the vocabulary and the ability to produce more words utterances at 2 years of age. Moreover, the results suggest that both “complementary” and “supplementary” crossmodal combinations are good predictive indexes of early verbal skills during the second year of age. (shrink)