Gestures are a form of intentional communication based on spontaneous hand movements that do not lead to (direct) physical changes in the external world (Cartmill, Beilock, & Goldin-Meadow, 2012; Cartmill, Demir, & Goldin-Meadow, 2012; McNeill, 1992; Tomasello, 2008). The meaning of a gesture cannot be extracted in isolation from the verbal or the physical context in which it unfolds. As McNeill (2005) shows, gestures have two basic features: they carry meaning and are co-expressive with the simultaneous speech. Also each gesture is created spontaneously. The fact that we tend to use similar gestures when we talk about a certain action, a relation or an object's properties (e.g., putting our fingers in a closed circle and taking it toward the mouth, to represent drinking from a cup) is a result of the fact that gestures illustrate perceptual regularities present in our shared world. Gestural communication is based on our memories about motor, visual and spatial experiences (LeBaron & Streeck, 2000), that we assume are similar for the other person. The receiver can understand the meaning of gestures because he/she recognizes the actions or the shapes they refer to. Similarly, the communicator uses gestures tacitly assuming that the receiver has the required experience for understanding their meaning. In this way, gestural communication is based on a common conceptual ground, on the shared knowledge of what "we both know together" (Tomasello, Carpenter, Call, Behne, & Moll, 2005).
According to common sense, gestures are a part of nonverbal behavior, reflecting a person's hidden attitudes or emotions. As such, the role of our hands and body when we gesture would be just to stress what we want to communicate via language: they neither interact, nor influence our cognition. Even in traditional cognitivism, cognition is separated from the rest of the body, from affect and emotions, and from the interaction with the physical and social world (Calvo & Gomila, 2008). The research pioneered by McNeill (1992) and Goldin-Meadow (2006) contradicts the common sense perspective that gesture is just hand waving. Gestures convey, and influence, knowledge. In other words, hand movements reflect, but are also intermingled with our cognitive processes while we speak.
An accruing body of evidence in cognitive science in the last two decades suggests that the traditional view about cognition does not reflect the way in which our cognitive system is functioning (Boroditsky & Prinz, 2008; Ionescu, 2011; Laakso, 2011; Smith & Sheya, 2010). Let's consider the case of concepts, usually regarded as the abstract pieces of knowledge that our minds process in an amodal and independent way, being stored in our semantic memory (Barsalou, 2008). Recent data show that our representations depend on the modal systems of the brain and that they are multi-modal simulations, in other words a "re-enactment of perceptual, motor and introspective states acquired during experience with the world, body and mind" (Barsalou, 2009, p. 1281; see also Barsalou, 2003; Gainotti, Spinelli, Scaricamazza, & Marra, 2013; Gallese & Lakoff, 2005; Martin, 2007). Evidence for the latter approach comes, for example, from studies that show that there are costs associated with verifying different-modality properties for concepts. For instance, verifying a visual property (such as baby clothes - pastel) is quicker if it comes after another visual property (such as hair - fair) than after a tactile property (such as toast - warm) (Pecher, Zeelenberg, & Barsalou, 2003). But even if this approach explains well concrete concepts, the embodiment of abstract thought is still an open question (Boroditsky & Prinz, 2008; Wilson, 2008).
Our aim in this paper is to analyze gesture and thought from an embodied perspective. In other words, we propose that gestures are an intermediate step in- between situation-bound cognition and abstract cognition. …