The developing bodily self: How posture constrains body representation in childhood

Abstract

Adults’ body representation is constrained by multisensory information and knowledge of the body such as its possible postures. This study (N = 180) tested for similar constraints in children. Using the rubber hand illusion with adults and 6- to 7-year-olds, we measured proprioceptive drift (an index of hand localisation) and ratings of felt hand ownership. The fake hand was either congruent or incongruent with the participant’s own. Across ages, congruency of posture and visual-tactile congruency yielded greater drift towards the fake hand. Ownership ratings were higher with congruent visual-tactile information, but unaffected by posture. Posture constrains body representation similarly in children and adults, suggesting that children have sensitive, robust mechanisms for maintaining a sense of bodily self.

My Virtual Self: The Role of Movement in Children's Sense of Embodiment

“…Finally, while we expected to see a shift in proprioceptive drift under conditions of movement synchrony as per previous findings [23], [37], [38], there were no differences in drift for any condition. One possibility is that, unlike previous research with children [23], [38], [58], proprioceptive drift was calculated by the distance between the two Oculus Touch controllers, held with clenched fists. The relatively large controllers may have resulted in less precise measurements and the hand clenching may have given proprioceptive signals to current hand position.…”

“…Since previous research has focused on adults, remarkably little is known about the role of body form in children. Infants have shown sensitivities to the configuration of their own legs [30], while 6-year-olds do not have a sense of ownership for a rubber hand with a different posture to their own [58]. However, in full body VR experiments, five-year-olds embodied a virtual body moving asynchronously to their own [59].…”

“…A control question was included to check whether participants were answering appropriately (see Table 1). These questions were based on previous similar measures of embodiment [2], [41] and our own work with children [9], [23], [38], [58]. For all questions, participants used a virtual laser beam whose origin was at the virtual hand to select a rating from a continuous response scale, ranging from 0 ("no, definitely not") to 1 ("yes, lots and lots").…”

“…Proprioceptive Drift Measures of proprioceptive drift are dominant in RHI studies [23], [37], [38], [58] and were included here to assess how VR experience affected the participant's perceived hand location. The virtual hand was offset by 25% of the participant's arm length (this was measured in cm from the top of the shoulder to the tip of the middle finger of the right hand).…”

“…The offset direction was set along the xaxis (running along the participant's left-right axis), towards the centre line of the body. This body-relative scaling was done to ensure that motor demands were the same for differently sized participants and replicates previous tabletop RHI studies [23], [38], [58]. A 1.2m wide horizontal pole clamped between two vertical poles ("H" shape with a long centre line) was placed in front of participants and height-adjusted up or down to be level with each participant's navel.…”