On the Tip of the Mind: Gesture as a Key to Conceptualization

On the Tip of the Mind: Gesture as a Key to Conceptualization Autumn B. Hostetter (abhostetter@wisc.edu) Department of Psychology, University of Wisconsin–Madison 1202 W. Johnson Street, Madison, WI 53706 USA Martha W. Alibali (mwalibali@wisc.edu) Department of Psychology, University of Wisconsin–Madison 1202 W. Johnson Street, Madison, WI 53706 USA Abstract model proposed by Levelt (1989), which divides the speech production process into three broad stages: conceptualization, formulation, and articulation. During conceptualization, the prelinguistic thoughts of a speaker are generated and combined into propositional form. During formulation, these thoughts are translated into the appropriate linguistic units by searching through the mental lexicon and identifying the proper lemmas and lexical entries. During articulation, the motor plan for pronouncing the phonemes corresponding to the lexemes is created and executed. It seems unlikely that the production of representational gestures influences motor aspects of articulation, and, indeed, research has typically focused on the earlier stages of speech production (conceptualization and formulation) as the possible beneficiaries of gesture. Work by Krauss and colleagues (Krauss, Chen, & Chawla, 1996) places the influence of gesture on speech as occurring primarily during the formulation stage. According to their view, referred to hereafter as the Lexical Access Hypothesis, gestures serve as a cross-modal prime to help speakers access specific items in the lexicon. In support of this view, a number of studies have shown that speakers produce more iconic gestures when the words of an utterance are more elusive (e.g. Hostetter & Hopkins, 2002; Morrel-Samuels & Krauss, 1992). For example, when speakers have time to verbally rehearse an utterance, they gesture less than when speaking completely extemporaneously (Chawla & Krauss, 1994). Similarly, speakers gesture more when describing ideas or shapes that are not readily named than when describing ideas or shapes that are easily named (Graham & Argyle, 1975; Morsella & Krauss, in press). Research with aphasic patients also suggests that gesture is involved in the formulation stage. Aphasic patients whose problems are primarily ones of lexical access use more gestures than age-matched controls (Hadar, Burstein, Krauss, & Soroker, 1998). Those whose problems are primarily not ones of lexical access produce fewer gestures than other types of aphasic patients (Hadar, Wenkert-Olenik, Krauss, & Soroker, 1998). Finally, prohibiting speakers from gesturing has been shown to negatively affect speech fluency, especially for speech that is spatial in nature (Rauscher et al, 1996). Studies that induce tip-of-the-tongue states have yielded slightly less compelling and more contradictory findings about the facilitative effects of gesture on formulation. Why do people gesture when they speak? The reasons are not entirely clear. This paper tests two hypotheses about the role of gesture in speech production: the Lexical Access Hypothesis, which holds that gesturing aids in lexical access, and the Information Packaging Hypothesis, which holds that gesturing aids in conceptualization. Participants were asked to describe dot patterns that were either easy or difficult to conceptualize in terms of geometric shapes. Patterns that were more difficult to conceptualize elicited more gesture than the patterns that were easier to conceptualize. This result supports the Information Packaging Hypothesis. Introduction It is often said that a picture is worth a thousand words. In the case of speech production, it sometimes seems that creating pictures with our hands can help our audience understand what we are saying. However, despite the intuitive feeling that we gesture primarily to help our audience, some research suggests that gestures contribute little to an audience’s understanding of a gesturer’s speech (Krauss, Morrel-Samuels, & Colasante, 1991; Krauss, Dushay, Chen, & Rauscher, 1995; but see Kendon, 1994 for an alternative perspective). Speakers often produce representational gestures even when they know that their audience cannot see them, making it unlikely that their intended purpose is solely to help the audience (Alibali, Heath, & Myers, 2001). This evidence that gesture does not help comprehension has led some investigators to propose that gesture has a more direct role in the speech production process, by facilitating the planning of speech. Specifically, gesture may play a role in speaking about ideas that are highly spatial or motoric in nature (Kita, 2002; Krauss & Hadar, 2001). It has been shown, for example, that gestures are more likely to coincide with words that are spatial and concrete (e.g., spin, under, or cube) than with words that are non-spatial and abstract (such as evil) (Krauss, 1998; Morsella & Krauss, in press; Rauscher, Krauss, & Chen, 1996). By actively engaging spatial-motoric ideas through gesture, it may become easier to speak about them. Although gesture may be an overt manifestation of spatio- motoric thought, exactly how gesture may facilitate speech production is still the subject of some debate. The majority of research in this area has followed the speech production