The role of functionality in the body model for self-attribution

Abstract

Bodily self-attribution, the feeling that a body (or parts of it) is owned by me, is a fundamental component of one's self. Previous studies have suggested that, in addition to a necessary multi-sensory stimulation, the sense of body ownership is determined by the body model, a representation of our body in the brain. It is however unclear what features constitute the body representation. To examine this issue, we first briefly review results on embodiment of artificial limbs, whole bodies and virtual avatars to understand the apparent anatomical, volumetric and spatial constraints associated with the sense of ownership toward external entities. We then discuss how considering limb functionality in the body model can provide an integrated explanation for most of the varied embodiment results in literature. We propose that the self-attribution of an entity may be determined, not just by its physical features, but by whether the entity can afford actions that the brain has associated with the limb which it replaces.

Object Touch by a Humanoid Robot Avatar Induces Haptic Sensation in the Real Hand

“…Our results demonstrate that nonanthropomorphic humanoid robots, when embodied, are able to induce haptic sensations in real environments. This result agrees with a recent proposal that the functional characteristics of a limb are more important than the physical features for embodiment (Aymerich‐Franch & Ganesh, ). The finding is also in line with previous studies that suggest that humans are able to embody avatar bodies that depart from the humanoid form (Ahn et al, ; Aymerich‐Franch, ; Aymerich‐Franch et al, , , ; Kilteni, Normand, Sanchez‐Vives, & Slater, ; Steptoe, et al, ; Won, et al, ).…”

“…This result agrees with a recent proposal that the functional characteristics of a limb are more important than the physical features for embodiment . The finding is also in line with previous studies that suggest that humans are able to embody avatar bodies that depart from the humanoid form (Ahn et al, 2016;Aymerich-Franch, 2012;Aymerich-Franch et al, 2015Kilteni, Normand, Sanchez-Vives, & Slater, 2012;Steptoe, et al, 2013;Won, et al, 2015).…”

“…While a resemblance of the shape of an artificial limb or body to a human body helps increase the sense of embodiment (Haans, IJsselsteijn, & de Kort, ), previous studies suggest that humans are also able to experience non‐human looking avatar and robot bodies as their own (Ahn, et al, ; Aymerich‐Franch, ; Aymerich‐Franch et al, , , ; Steptoe, Steed, & Slater, ; Won, Bailenson, Lee, & Lanier, ). Thus, we hypothesized that an anthropomorphic limb is not essential for embodiment (Aymerich‐Franch & Ganesh, ), and that a non‐anthropomorphic limb can induce illusory haptic perceptions provided that a sense of embodiment is induced towards it. Our results support this hypothesis.…”

Forward modelling the rubber hand: illusion of ownership modifies motor-sensory predictions by the brain

“…However, our results suggest the observed premotor and cerebellar activations, which have been previously associated with the loading of an internal model [42] and sensory predictions of self-generated movements [21], may partially be the result of modifications of forward models during the RHI. Furthermore, our result supports a recent suggestion of an action based coding of the body model for self-attribution [43] and is encouraging for embodiment applications in therapy [44] and prosthetics [41] as it shows again that illusions of embodiment and the resulting ownership can be utilized to rapidly influence not just the sensory but also the motor control processes in an individual's brain.…”

Body-Borne Computers as Extensions of Self

“…For instance, the discussion by Aymerich-Franch and Ganesh [23] addresses the effect of (the body's) functionality in self-attribution. However, few works [17] have studied the relationship between embodiment and its interaction with the world or tasks.…”