Gestures are often considered to be valid evidence of the embodiment of language and cognition. Since people use their bodies (i.e., gestures) to express knowledge, it is argued, the knowledge itself must be deeply tied to the body (Alibali & Nathan, 2007;Gallagher, 2005;Gibbs, 2006;Hostetter & Alibali, 2004;McNeill, 2005;Nuñez, 2005). This claim may hold some truth, but to date, there have been no explicit proposals about how embodied knowledge comes to be reflected in speech-accompanying gestures. The goal of this article is to explore how gestures may arise from embodied thinking; we will approach this goal by integrating research about perception, action, cognition, language, mental imagery, and gesture production.A variety of hand and body movements can be considered to be gestures, and much previous research has sought to describe these different types of gestures (e.g., Efron, 1972;Kendon, 2004;McNeill, 1992). In this article, we limit our discussion to representational gestures-that is, movements that represent the content of speech by pointing to a referent in the physical environment (deictic gestures), depicting a referent with the motion or shape of the hands (iconic gestures), or depicting a concrete referent or indicating a spatial location for an abstract idea (metaphoric gestures). We use the term gestures to refer specifically to representational gestures. Other types of gestures, including beat gestures (movements that emphasize the prosody or structure of speech without conveying semantic information) and interactive gestures (movements used to manage turn taking and other aspects of an interaction between multiple speakers), fall outside the scope of this article.Our aim is to describe a mechanism that may possibly give rise to gestures. We do not seek to address the issue of the functions of gestures (e.g., in communication, in speech production). Although we review some ideas about the functions of gestures, we do not take a strong stance here regarding gesture function. The goal of our framework is to explain what gestures are, rather than what they do.The article proceeds in seven sections. In the first section, we review ideas about links between perception and action and how these links are important in memory and cognition. In the second section, we review evidence that language processing is tied to the body. In the third section, we review evidence that mental imagery is also an embodied process. In the fourth section, we review evidence on the relationship between gesture production and mental imagery, and in the fifth, we propose a theoretical framework that explains how gestures may arise from the activation of perception and action. In the sixth section, we compare our framework with other models of gesture production. Finally, in the seventh section, we articulate predictions that derive from the framework. Perception, Action, and Embodied CognitionMany theorists have proposed that perception is for action (J. J. Gibson, 1979;Sperry, 1952); that is, the ability to perceive evolv...

Do the gestures that speakers produce while talking significantly benefit listeners' comprehension of the message? This question has been the topic of many research studies over the previous 35 years, and there has been little consensus. The present meta-analysis examined the effect sizes from 63 samples in which listeners' understanding of a message was compared when speech was presented alone with when speech was presented with gestures. It was found that across samples, gestures do provide a significant, moderate benefit to communication. Furthermore, the magnitude of this effect is moderated by 3 factors. First, effects of gesture differ as a function of gesture topic, such that gestures that depict motor actions are more communicative than those that depict abstract topics. Second, effects of gesture on communication are larger when the gestures are not completely redundant with the accompanying speech; effects are smaller when there is more overlap between the information conveyed in the 2 modalities. Third, the size of the effect of gesture is dependent on the age of the listeners, such that children benefit more from gestures than do adults. Remaining questions for future research are highlighted.

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This study examined the communicative behavior of 49 captive chimpanzees (Pan troglodytes), particularly their use of vocalizations, manual gestures, and other auditory- or tactile-based behaviors as a means of gaining an inattentive audience's attention. A human (Homo sapiens) experimenter held a banana while oriented either toward or away from the chimpanzee. The chimpanzees' behavior was recorded for 60 s. Chimpanzees emitted vocalizations faster and were more likely to produce vocalizations as their 1st communicative behavior when a human was oriented away from them. Chimpanzees used manual gestures more frequently and faster when the human was oriented toward them. These results replicate the findings of earlier studies on chimpanzee gestural communication and provide new information about the intentional and functional use of their vocalizations.

Hand preferences for a coordinated bimanual task were assessed in 109 chimpanzees (Pan troglodytes). Hand preference was evaluated for 4 test sessions using bouts and frequencies of hand use to compare the sensitivity of each level of analysis in evaluating individual variation in handedness. Overall, significant population-level right-handedness was found using several different measures of hand use. Handedness indices based on bouts and frequencies were highly and significantly correlated. Moreover, hand preferences were consistent across tests despite efforts to situationally bias preference during each test. Taken together, these data do not support the view that bouts are a better level of analysis for evaluating hand preference. The results further suggest that hand preferences for coordinated bimanual actions are not influenced by situational factors and may reflect an inherent specialization of the left hemisphere for motor skill.The issue of whether nonhuman primates exhibit population-level handedness has been a topic of historical and recent debate (Ettlinger, 1988;Fagot & Vauclair, 1991;MacNeilage, StuddertKennedy, & Lindblom, 1987;Marchant & McGrew, 1991;Ward & Hopkins, 1993;Warren, 1980 NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript sample display the same directional bias in hand use. The historical view held that handedness was bimodally distributed in nonhuman species including primates (Warren, 1980), but this view has recently been challenged by a host of behavioral Studies (see Bradshaw & Rogers, 1993;Hook-Costigan & Rogers, 1997;Hopkins, 1996;Hopkins & Morris, 1993;Lehman, 1993;Ward, Milliken, & Stafford, 1993, for reviews). Of specific interest to this article is the evidence of population-level right-handedness in chimpanzees and other great apes. Some have argued that there is a 2:1 ratio of right-to left-handed individuals (Corballis, 1997;Hopkins, 1999b;Hopkins & Pearson, 2000). In contrast, others have argued that the evidence is weak for population-level right-handedness in apes and that some Studies reporting evidence of population-level right-handedness are methodologically or statistically flawed (McGrew & Marchant, 1997).Presently, the debate over whether great apes (and other nonhuman primates) exhibit population-level hand preference centers on two issues, both of which are subject to different interpretation. One issue is whether population-level right-handedness is restricted to captive populations of apes, and this issue is not addressed in this article. The second issue, which is addressed in this article, is whether the use of frequencies contrasted with bouts of lateralized behavior reflects the same or different manifestations of lateral bias at the individual and population level. Specifically, Marchant (1994,1997), as well as others (Boesch, 1991;Byrne & Byrne, 1991), have argued that bouts are a better measure of laterality in hand use than the use of the raw frequencies. The central premise of this argument, outlined by McGrew and ...