In our everyday life, we have the genuine feeling that when something we use works very well, we forget that we are doing something that is mediated by something else. It happens when we read through our glasses, or when we drive home, or when we play guitar. In all those cases, it can be said that the device becomes an extension of our body, or that we have incorporated it. In this paper I want to discuss the extension/incorporation dichotomy (...) as presented in contemporary cognitive sciences. I will present the state of the art in the debate in order to promote a methodological shift, namely to adopt two concept borrowed from Material Engagement Theory developed by Lambros Malafouris. By advocating the concepts of temporality and metaplasticity, I will argue for two different but related things: 1) extension and incorporation don’t have to be conceived only spatially, but temporally. This shift leads to two distinctive implications: first, the sooner two entities establish a prosthetic contact, the higher the chances to reach incorporation; second, extension temporally precedes incorporation; the former being an early-staged phenomenon of – a condition of possibility for – the latter. 2) Such a temporal perspective is at the base of metaplasticity, which describes, in the context of MET, the constant, co-constitutive loop between humans and things: metaplasticity deflates the privileged role traditionally attributed to the subject in the making of phenomenal experience. Finally, I will discuss extension and incorporation in media theory, relying on the concept of radical mediation. (shrink)

Objects which a human agent controls by efferent activities can be perceived by the agent as belonging to his or her body. This suggests that what an agent counts as “body” is plastic, depending on what she or he controls. Yet there are possible limitations for such momentary plasticity. One of these limitations is that sensations stemming from the body and sensations stemming from objects outside the body are not integrated if they do not sufficiently “match”. What “matches” and what (...) does not is conceivably determined by long–term experience with the perceptual changes that body movements typically produce. Children have accumulated less sensorimotor experience than adults have. Consequently, they express higher flexibility to integrate body-internal and body-external signals, independent of their “match” as suggested by rubber hand illusion studies. However, children’s motor performance in tool use is more affected by mismatching body-internal and body-external action effects than that of adults, possibly because of less developed means to overcome such mismatches. We review research on perception-action interactions, multisensory integration, and developmental psychology to build bridges between these research fields. By doing so, we account for the flexibility of the sense of body ownership for actively controlled events and its development through ontogeny. This gives us the opportunity to validate the suggested mechanisms for generating ownership by investigating their effects in still developing and incomplete stages in children. We suggest testable predictions for future studies investigating both body ownership and motor skills throughout the lifespan. (shrink)

Body representations are known to be dynamically modulated or extended through tool use. Here, we review findings that demonstrate the importance of a user's tool experience or expertise for successful tool embodiment. Examining expert tool users, such as individuals who use tools in professional sports, people who use chopsticks at every meal, or spinal injury patients who use a wheelchair daily, offers new insights into the role of expertise in tool embodiment: Not only does tool embodiment differ between novices and (...) experts, but experts may experience enhanced changes to their body representation when interacting with their own, personal tool. The findings reviewed herein reveal the importance of assessing tool skill in future studies of tool embodiment. (shrink)