In recent years, social cognition approaches to human evolution and Material Engagement Theory have offered new theoretical resources to advance our understanding of the prehistoric hominin mind. To date, however, these two approaches have developed largely in isolation from one another. I argue that there is a gap between social- and material-centred approaches, and that this is precisely the sociomateriality of the appearance of ancestral hominin bodies, which evolved under selective pressure to develop increasingly complex, cooperative sociality. To get this (...) sociomaterial body in focus, I develop an esthesiological framework, appropriated from Merleau-Ponty (2003), for interpreting the expressive body in an evolutionary and comparative context. The guiding hypothesis of esthesiology is that before being rationality (social or material), “humanity is another corporeity” (Merleau-Ponty, 2003, p. 208). Esthesiology studies the appearance of the body and its sense organs as an intertwining locus of a sensing power (the ability to see, to touch, etc.) and a sensible character (the visible, touchable body). It is this dual-aspect character of the body that facilitates the most basic affective and sensorimotor modes of sociality. Examining these features from a comparative perspective, we find that the human body is distinctively suited to prosocial communication and cooperation: a more cooperative eye, an exposed and communicative skin. I thus propose a cooperative body hypothesis, by analogy with the cooperative eye hypothesis (Tomasello et al., 2007). Esthesiology provides a framework for integrating and interpreting a wide range of otherwise disconnected facts concerning human and nonhuman animal bodies, forms of life, cognition, and evolution, thereby bridging the gap between social cognition and material engagement perspectives. In doing so, however, it not only solves problems and proposes new directions of investigation, but also demands theoretical revisions from each. (shrink)