Publications

Abstract

Gestures express redundant or complementary information to speech they accompany by depicting visual and spatial features of referents. In doing so, they recruit both spatial and verbal cognitive resources that underpin the processing of visual semantic information and its integration with speech. The relation between spatial and verbal skills and gesture comprehension, where gestures may serve different roles in relation to speech is yet to be explored. This study examined the role of spatial and verbal skills in processing gestures that expressed redundant or complementary information to speech during the comprehension of spatial relations between objects. Turkish-speaking adults (N=74) watched videos describing the spatial location of objects that involved perspective-taking (left-right) or not (on-under) with speech and gesture. Gestures either conveyed redundant information to speech (e.g., saying and gesturing “left”) or complemented the accompanying demonstrative in speech (e.g., saying “here,” gesturing “left”). We also measured participants’ spatial (the Corsi block span and the mental rotation tasks) and verbal skills (the digit span task). Our results revealed nuanced interactions between these skills and spatial language comprehension, depending on the modality in which the information was expressed. One insight emerged prominently. Spatial skills, particularly spatial working memory capacity, were related to enhanced comprehension of visual semantic information conveyed through gestures especially when this information was not present in the accompanying speech. This study highlights the critical role of spatial working memory in gesture processing and underscores the importance of examining the interplay among cognitive and contextual factors to understand the complex dynamics of multimodal language.

Abstract

In spoken languages, children acquire locative terms in a cross-linguistically stable order. Terms similar in meaning to in and on emerge earlier than those similar to front and behind, followed by left and right. This order has been attributed to the complexity of the relations expressed by different locative terms. An additional possibility is that children may be delayed in expressing certain spatial meanings partly due to difficulties in discovering the mappings between locative terms in speech and spatial relation they express. We investigate cognitive and mapping difficulties in the domain of spatial language by comparing how children map spatial meanings onto speech versus visually motivated forms in co-speech gesture across different spatial relations. Twenty-four 8-year-old and 23 adult native Turkish-speakers described four-picture displays where the target picture depicted in-on, front-behind, or left-right relations between objects. As the complexity of spatial relations increased, children were more likely to rely on gestures as opposed to speech to informatively express the spatial relation. Adults overwhelmingly relied on speech to informatively express the spatial relation, and this did not change across the complexity of spatial relations. Nevertheless, even when spatial expressions in both speech and co-speech gesture were considered, children lagged behind adults when expressing the most complex left-right relations. These findings suggest that cognitive development and mapping difficulties introduced by the modality of expressions interact in shaping the development of spatial language.

Abstract

Gesture and speech are assumed to form an integrated system during language production. Based on this view, we propose the integrated‐systems hypothesis, which explains two ways in which gesture and speech are integrated—through mutual and obligatory interactions—in language comprehension. Experiment 1 presented participants with action primes (e.g., someone chopping vegetables) and bimodal speech and gesture targets. Participants related primes to targets more quickly and accurately when they contained congruent information (speech: “chop”; gesture: chop) than when they contained incongruent information (speech: “chop”; gesture: twist). Moreover, the strength of the incongruence affected processing, with fewer errors for weak incongruities (speech: “chop”; gesture: cut) than for strong incongruities (speech: “chop”; gesture: twist). Crucial for the integrated‐systems hypothesis, this influence was bidirectional. Experiment 2 demonstrated that gesture’s influence on speech was obligatory. The results confirm the integrated‐systems hypothesis and demonstrate that gesture and speech form an integrated system in language comprehension.

Abstract

Locative expressions encode the spatial relationship between two (or more) entities. In this paper, we focus on locative expressions in signed language, which use the visual-spatial modality for linguistic expression, specifically in
Turkish Sign Language ( Türk İşaret Dili, henceforth TİD). We show that TİD uses various strategies in discourse to encode the relation between a Ground entity (i.e., a bigger and/or backgrounded entity) and a Figure entity (i.e., a
smaller entity, which is in the focus of attention). Some of these strategies exploit affordances of the visual modality for analogue representation and support evidence for modality-specific effects on locative expressions in sign languages.
However, other modality-specific strategies, e.g., the simultaneous expression of Figure and Ground, which have been reported for many other sign languages, occurs only sparsely in TİD. Furthermore, TİD uses categorical as well as analogical structures in locative expressions. On the basis of
these findings, we discuss differences and similarities between signed and spoken languages to broaden our understanding of the range of structures used in natural language (i.e., in both the visual-spatial or oral-aural modalities) to encode locative relations. A general linguistic theory of spatial relations, and specifically of locative expressions, must take all structures that
might arise in both modalities into account before it can generalize over the human language faculty.

Abstract

Gestures that spontaneously accompany speech convey information coordinated with the concurrent speech. There has been considerable theoretical disagreement about the process by which this informational coordination is achieved. Some theories predict that the information encoded in gesture is not influenced by how information is verbally expressed. However, others predict that gestures encode only what is encoded in speech. This paper investigates this issue by comparing informational coordination between speech and gesture across different languages. Narratives in Turkish, Japanese, and English were elicited using an animated cartoon as the stimulus. It was found that gestures used to express the same motion events were influenced simultaneously by (1) how features of motion events were expressed in each language, and (2) spatial information in the stimulus that was never verbalized. From this, it is concluded that gestures are generated from spatio-motoric processes that interact on-line with the speech production process. Through the interaction, spatio-motoric information to be expressed is packaged into chunks that are verbalizable within a processing unit for speech formulation. In addition, we propose a model of speech and gesture production as one of a class of frameworks that are compatible with the data.