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The plasticity of the self: experimenting with self-identity in the face of change

Final Report Summary - PLASTICSELF (The plasticity of the self: experimenting with self-identity in the face of change)

We normally entertain a fairly continuous and stable sense of personal identity, as we acknowledge that we are the same person, independently of what happens to us. The question of how our sense of self is maintained or changed across time is a key topic in psychology. Our self must possess sufficient plasticity, that is, adaptive processes of re-organization, to ensure assimilation of changes and a sense of continuity over time. To study the plasticity of the self, we investigated how the experience of a changing body updates or alters our sense of self, in two parallel projects. First, we focused on how we come to recognize our face. Our face is the most distinctive feature of our physical appearance, and one of the key ways by which we become known as individuals, both to ourselves and to others. As such, our ability to recognize and represent ourselves is a key feature of self-awareness and identity. We studied how we acquire, maintain or update a mental representation of how we look like. We did so by testing individuals before and after reconstructive surgery and face-transplantation, as well as healthy adults and infants, using experimental psychology and functional neuroimaging methods. Our findings have unearthed the key brain areas that form a part of a self-recognition network in the brain. Importantly, we identified the role of distinct mechanisms: in addition to storing memory representations of how we look like, our brain continuously integrates sensory information such as vision and touch to check whether the actual appearance matches a stored representation of our facial identity, and eventually to update the mental representation of our self. This process, underpinned by multimodal brain areas, guarantees the continuity but also the update of our body-image.
Second, we asked how our own body-image affects the way we perceive other people. We addressed this second question by investigating how changes in how our own body is represented in the brain, caused by experimental manipulations, can consequently affect social cognition processes, using experimental and social psychology methods. For example, we asked whether people can experience a hand of a different skin colour as their own and whether this would change possible racial biases. Using Caucasian participants, we tested their implicit attitudes towards people with dark skin before using a dark-skinned rubber hand to make them feel as if dark hand was their own. We then tested their racial attitudes again after the experiment. The results showed that the more intense the participants’ illusion of owning the dark-skinned hand, the more positive their racial attitudes became. The same findings were replicated in subsequent studies that also highlighted the plastic changes in the underpinning neural network. Taken together, these findings have important implications for changing and reducing negative racial attitudes. Our results show that we can positively alter social stereotypes by capitalizing on the way in which the brain is processing sensory information from our bodies and that of others. We thus show that a fundamental component of several social cognition processes, such as implicit attitudes, empathy, emotion processing, is guided by the ways in which we perceive ourselves to be physically similar, or not, to others.
Overall, the PLASTISELF project provided key insights in our scientific understanding of self-awareness. Our results show that our self-awareness is constructed by the integration of various sensory signals, and that in a similar way, the perceived physical similarity between us and others is influenced by the sensory experiences that we share with them. Consequently, the way in which our brain uses sensory information to construct a model of self is also used to gauge our social relations. Overall, this project asked a fundamental basic science question about self-awareness. The question of the plasticity of the self is timely, because the modern self, due to societal, technological and medical advances, seems to be exposed to new, often radical, possibilities of change. PLASTICSELF succeeded in providing novel insights in answering this question by understanding the basic mechanisms behind the plasticity of the self, by integrating research methods from experimental and social psychology, cognitive neurosciences, and medicine in wide-ranging and innovative ways, that have and will continue to have substantial impact within and beyond academia.