The Developing Bodily Self: How Posture Constrains Body Representation in Childhood, 2017-2021

Cowie, Dorothy and Gottwald, Janna and Bird, Laura-Ashleigh and Bremner, Andrew J (2022). The Developing Bodily Self: How Posture Constrains Body Representation in Childhood, 2017-2021. [Data Collection]. Colchester, Essex: UK Data Service. 10.5255/UKDA-SN-855465

Perceiving one's own body is crucial for being able to perceive the world and act on it. But how do we do this? Imagine that I can see two hands resting on the table in front of me. One is mine, and one belongs to my friend. How do I tell which is which? This seems like an obvious question, but on consideration it is not. In fact, research has told us that adults use several different types of information, including multisensory visual, tactile, and movement cues; and stored knowledge about the form of their own hand. A more difficult question is how children manage to identify their own bodies in the midst of the constant growth and change which occurs in childhood. Very little is known about this. In particular, it is unclear how children balance the need for a consistent idea of their own body, and the need to be flexible as it grows. Further, new virtual reality technologies are emerging which can provide virtual bodies to children in games or educational settings. How might children accept and use these virtual bodies?

This 3-year project addresses these issues by investigating how children and adults perceive their own bodies, and how this grounds the emerging sense of bodily self. We will run five carefully designed experiments, building on methods which we have previously used successfully with children. The project team have the theoretical and technical backgrounds necessary to carry out this pioneering work; our lab has suitable equipment; and the proposal includes previous published and pilot data showing the feasibility of the approach.

We will experimentally examine own-body representation using the 'Rubber Hand Illusion'. The participant sees a fake hand on the table in front of them while their real hand is hidden. An experimenter strokes the hands at the same time. This makes the participant feel as if the fake hand is their own. Further, when asked to point underneath their own hand, they point near the fake hand. We have recently shown that 4 - 13-year-old children experience this illusion. Here, we will measure what happens when the size or shape of the fake hand is changed. If participants experience the illusion less in these cases, it shows that they have expectations for how their hand should look. Based on previous work, Experiments 1 and 2 will test the hypotheses that both children and adults will expect that a hand must be five-fingered; and that the hand must be approximately the right size. Crucially we will also determine whether there is plasticity in these body representations, enabling children to accept for example larger hands than their own to account for growth. Experiments 3-5 will examine how body representation may change given experience of a moving body. Do children learn more quickly from experience more than adults, for example requiring less movement experience to accept an oversized hand? How does touch information combined with movement in forming a sense of the bodily self? What are the limits of what children will accept as their own body in such an environment?

The academic outputs of the project will provide vital new information on how children represent their bodies. This is an interdisciplinary project between Psychology and Computer Science, and its findings will be of major significance and interest across a range of disciplines - Psychology, Computer Science, Philosophy, and Cognitive Science. The work will also have non-academic impact. We will communicate findings to designers of virtual reality games, as well as healthcare practitioners developing bionic arms or using virtual rehabilitation programmes. Finally we will use the work as a springboard to invite volunteer children to a series of workshops examining the senses and movement. Through these we hope to encourage them towards STEM activities or careers.

Data description (abstract)

For adults, the feeling of inhabiting a body (a sense of embodiment) is constrained by bottom-up multisensory information such as spatiotemporal correlations between visual and tactile sensations, and by top-down knowledge of the body such as its possible postures. However, to date it is unknown what kinds of body models children have. Here we asked whether common factors constrain embodiment in children and adults. In two experiments, we compared 6- to 7-year-olds’ and adults’ embodiment of a fake hand in the rubber hand illusion, measuring illusion-induced proprioceptive drift and questionnaire responses. In Experiment 1 (N = 120), the fake hand was either congruent with the participant’s own hand, or incongruent by 90° and, as a result, in an impossible posture with respect to the current position of their body. In Experiment 2 (N = 60), the fake hand was incongruent with the participant’s own hand by 20°, but still in a possible posture. Across both experiments, and in both children and adults, visual-proprioceptive congruency of posture, and visual-tactile spatiotemporal congruency in stroking independently yielded greater proprioceptive drift towards the rubber hand. Subjective ratings of embodiment were also higher when visual-tactile information was congruent, but were not affected by posture. Top-down knowledge of body posture therefore partially constrains embodiment in middle childhood, as in adulthood. This shows that, although childhood is a period of significant change in both bodily dimensions and sensory capabilities, 6- to 7-year-olds have sensitive, robust mechanisms for maintaining a sense of bodily self.

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