How does our body affect the way we think about our personality? We addressed this question by eliciting the perceptual illusion that pairs of friends swapped bodies with each other. We found that during the illusion, the participants rated their own personality characteristics more similarly to the way they previously rated their friend's personality, and this flexible adjustment of self-concept to the ''new'' bodily self was related to the strength of illusory ownership of the friend's body. Moreover, a subsequent memory test showed that personality traits rated during the friend-body-swap illusion were generally remembered worse than traits rated during the control conditions; importantly, however, this impairment of episodic recognition memory was reduced for the participants who considerably adjusted their self-concept during the illusory body swapping. These findings demonstrate that our beliefs about own personality are dynamically shaped by the perception of our body and that coherence between the bodily and conceptual self-representations is important for the normal encoding of episodic memories.

The loss of body ownership, the feeling that your body and its limbs no longer belong to you, presents a severe clinical condition that has proven difficult to study directly. We here propose a novel paradigm using mixed reality to interfere with natural embodiment using temporally conflicting sensory signals from the own hand. In Experiment 1 we investigated how such a mismatch affects phenomenological and physiological aspects of embodiment, and identified its most important dimensions using a principle component analysis. The results suggest that such a mismatch induces a strong reduction in embodiment accompanied by an increase in feelings of disownership and deafference, which was, however, not reflected in physiological changes. In Experiment 2 we refined the paradigm to measure perceptual thresholds for temporal mismatches and compared how different multimodal, mismatching information alters the sense of embodiment. The results showed that while visual delay decreased embodiment both while actively moving and during passive touch, the effect was stronger for the former. Our results extend previous findings as they demonstrate that a sense of disembodiment can be induced through controlled multimodal mismatches about one's own body and more so during active movement as compared to passive touch. Based on the ecologically more valid protocol we propose here, we argue that such a sense of disembodiment may fundamentally differ from disownership sensations as discussed in the rubber hand illusion literature, and emphasize its clinical relevance. This might importantly advance the current debate on the relative contribution of different modalities to our sense of body and its plasticity.

Altered states of embodiment are fundamental to the scientific understanding of bodily self consciousness. The feeling of disembodiment during everyday activities is common to clinical conditions; however, the direct study of disembodiment in experimental setups is rare compared to the extensive investigation of illusory embodiment of an external object. Using mixed reality to modulate embodiment through temporally mismatching sensory signals from the own body, we assessed how such mismatches affect phenomenal and physiological aspects of embodiment and measured perceptual thresholds for these across multimodal signals. The results of a principal component analysis suggest that multimodal mismatches generally induce disembodiment by increasing the sense of disownership and deafference and decreasing embodiment; however, this was not generally reflected in physiological changes. Although visual delay decreased embodiment both during active movement and passive touch, the effect was stronger for the former. We discuss the relevance of these findings for understanding bodily self plasticity.

Interoception, the perception of internal bodily signals, is fundamental to our sense of self. Even though theoretical accounts suggest an important role for interoception in the development of the self, empirical investigations are limited, in particular, in infancy. Previous studies used preferential-looking paradigms to assess the detection of sensorimotor and multisensory contingencies in infancy, usually related to proprioception and touch. So far, only one single recent study reported that infants discriminated audiovisual stimuli that were presented synchronous or asynchronous with their heartbeat. This discrimination was related to the amplitude of the infant’s heartbeat evoked potentials (HEP), a neural correlate of interoception. In the current study, we measured looking preferences between synchronous and asynchronous visuocardiac (bimodal), and audiovisuocardiac (trimodal) stimuli as well as the HEP in conditions of different emotional contexts and with different degrees of self- relatedness in a mirror-like setup. While the infants preferred trimodal to bimodal stimuli, we did not observe the predicted differences between synchronous and asynchronous stimulation. Furthermore, the HEP was not modulated by either the emotional context or by the self-relatedness. These findings contradict previously published findings and highlight the need for further studies on the early development of interoception in relation to the development of the self.

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The sense of a bodily self is thought to depend on adaptive weighting and integration of bodily afferents and prior beliefs. Evidence from studies using paradigms such as the rubber hand illusion and full body illusion suggests changes in the integration of visuotactile bodily signals throughout childhood. Here, we extended this line of research by assessing how bottom-up visuomotor synchrony and expectancy, modulated by visual appearance of virtual avatars, contribute to embodiment in children. We compared responses to a first-person perspective virtual full body illusion from 8-12-year-old children and adults, while manipulating synchrony of the avatar’s movements (synchronous, 0.5 s, 1 s delay compared to the participant’s movements), and appearance of the avatar (human or skeleton). We measured embodiment with both subjective questionnaires and objective skin conductance responses to virtual threat. Results showed that children experienced ownership for the virtual avatar in a similar way to adults, which was reduced with increasing asynchrony, and for the skeleton avatar as compared to the human avatar. This modulation of ownership was not reflected in the skin conductance responses, which were equally high in all experimental conditions and only showed a modulation of repetition by age. Contrastingly, in children, the subjective experience of agency was less affected by the dampening effects of visuomotor asynchrony or reduced human likeness, and overall higher. These findings suggest that children can easily embody a virtual avatar, but that different aspects of embodiment develop at different rates, which could have important implications for applications of embodied virtual reality.