Rhesus monkeys have an interoceptive sense of their beating hearts.

The sensation of internal bodily signals, such as when your stomach is contracting or your heart is beating, plays a critical role in broad biological and psychological functions ranging from homeostasis to emotional experience and self-awareness. The evolutionary origins of this capacity and, thus, the extent to which it is present in nonhuman animals remain unclear. Here, we show that rhesus monkeys (Macaca mulatta) spend significantly more time viewing stimuli presented asynchronously, as compared to synchronously, with their heartbeats. This is consistent with evidence previously shown in human infants using a nearly identical experimental paradigm, suggesting that rhesus monkeys have a human-like capacity to integrate interoceptive signals from the heart with exteroceptive audiovisual information. As no prior work has demonstrated behavioral evidence of innate cardiac interoceptive ability in nonhuman animals, these results have important implications for our understanding of the evolution of this ability and for establishing rhesus monkeys as an animal model for human interoceptive function and dysfunction. We anticipate that this work may also provide an important model for future psychiatric research, as disordered interoceptive processing is implicated in a wide variety of psychiatric conditions.

The Self in the Mind's Eye: Revealing How We Truly See Ourselves Through Reverse Correlation.

Is there a way to visually depict the image people "see" of themselves in their minds' eyes? And if so, what can these mental images tell us about ourselves? We used a computational reverse-correlation technique to explore individuals' mental "self-portraits" of their faces and body shapes in an unbiased, data-driven way (total N = 116 adults). Self-portraits were similar to individuals' real faces but, importantly, also contained clues to each person's self-reported personality traits, which were reliably detected by external observers. Furthermore, people with higher social self-esteem produced more true-to-life self-portraits. Unlike face portraits, body portraits had negligible relationships with individuals' actual body shape, but as with faces, they were influenced by people's beliefs and emotions. We show how psychological beliefs and attitudes about oneself bias the perceptual representation of one's appearance and provide a unique window into the internal mental self-representation-findings that have important implications for mental health and visual culture.

Embodying an invisible face shrinks the cone of gaze.

The possibility of being invisible has long fascinated people. Recent research showed that multisensory illusions can induce experiences of bodily invisibility, allowing the psychological consequences of invisibility to be explored. Here, we demonstrate an illusion of embodying an invisible face. Participants received touches on their face and simultaneously saw a paintbrush moving synchronously in empty space and defining the shape of an invisible face. Using both explicit questionnaire measures (Experiment 1) and implicit physiological measures (Experiment 2), we show that such invisible enfacement induces a sense of ownership. We further demonstrate that embodying an invisible face shrinks the width of the cone of gaze (i.e., the range of eye deviations people judge as directed toward themselves; Experiments 3 and 4). These results suggest that the experience of invisibility affects the way in which we process the attention of others toward the self, starting from the perception of gaze direction. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The Erogenous Mirror: Intersubjective and Multisensory Maps of Sexual Arousal in Men and Women.

Erogenous zones of the body are sexually arousing when touched. Previous investigations of erogenous zones were restricted to the effects of touch on one's own body. However, sexual interactions do not just involve being touched, but also involve touching a partner and mutually looking at each other's bodies. We take a novel interpersonal approach to characterize the self-reported intensity and distribution of erogenous zones in two modalities: touch and vision. A large internet sample of 613 participants (407 women) completed a questionnaire, where they rated intensity of sexual arousal related to different body parts, both on one's own body and on an imagined partner's body in response to being touched but also being looked at. We report the presence of a multimodal erogenous mirror between sexual partners, as we observed clear correspondences in topographic distributions of self-reported arousal between individuals' own bodies and their preferences for a partner's body, as well as between those elicited by imagined touch and vision. The erogenous body is therefore organized and represented in an interpersonal and multisensory way.

Self or (M)other? Infants' Sensitivity to Bodily Overlap With Their Mother Reflects Their Dyadic Coordination.

Adults experience greater self-other bodily overlap in romantic than platonic relationships. One of the closest relationships is between mother and infant, yet little is known about their mutual bodily representations. This study measured infants' sensitivity to bodily overlap with their mother. Twenty-one 6- to 8-month-olds watched their mother's face or a stranger's face being stroked synchronously versus asynchronously with their own face. Infants preferred synchrony only when viewing their mother, not when viewing the stranger. Infants who strongly preferred synchrony with their mother also experienced less coordination with her in naturalistic interactions. Infants thus appear sensitive to bodily overlap with their mother, and this overlap reflects dyadic coordination, supporting theoretical accounts of intersubjectivity in the development of the bodily self.

Neurobehavioral evidence of interoceptive sensitivity in early infancy.

Interoception, the sensitivity to visceral sensations, plays an important role in homeostasis and guiding motivated behaviour. It is also considered to be fundamental to self-awareness. Despite its importance, the developmental origins of interoceptive sensitivity remain unexplored. We here provide the first evidence for implicit, flexible interoceptive sensitivity in 5 month old infants using a novel behavioural measure, coupled with an established cortical index of interoceptive processing. These findings have important implications for the understanding of the early developmental stages of self-awareness, self-regulation and socio-emotional abilities.

You Fill My Heart: Looking at One's Partner Increases Interoceptive Accuracy.

The integration of external and internal bodily signals provides a coherent, multisensory experience of one's own body. The ability to accurately detect internal bodily sensations is referred to as interoceptive accuracy (IAcc). Previous studies found that IAcc can be increased when people with low IAcc engage in self-processing such as when looking in the mirror or at a photograph of one's own face. However, the way the self is represented changes depending on the context. Specifically, in social situations, the self is experienced in relation to significant others and not as an isolated individual. Intriguingly, in a relational context romantic partners can be used as social mirrors for one's self. We here investigated whether directing one's attention to romantic partners would enhance one's IAcc, similar to the effect of self-face observation when the self is processed in isolation. During a heartbeat counting task, both concurrent self-face and partner-face observation improved accuracy in those with initially low IAcc; however, this improvement was significantly greater for the partner's face. These results suggest that significant others may play an important role in determining the quality of one's self-awareness. Given that high interoceptive awareness is linked to better emotion regulation, increased IAcc during partner observation is likely to have an adaptive role in maintaining stable and secure romantic relationships through greater emotion regulation.

Can the self become another? Investigating the effects of self-association with a new facial identity.

The mental representation of the self is a complex construct, comprising both conceptual information and perceptual information regarding the body. Evidence suggests that both the conceptual self-representation and the bodily self-representation are malleable, and that these different aspects of the self are linked. Changes in bodily self-representation appear to affect how the self is conceptualized, but it is unclear whether the opposite relationship is also true: Do changes to the conceptual self-representation affect how the physical self is perceived? First, we adopted a perceptual matching paradigm to establish an association between the self and an unfamiliar face (Experiment 1). Robust attentional and perceptual biases in the processing of this newly self-associated object suggested that the conceptual self-representation was extended to include it. Next, we measured whether the bodily self-representation had correspondingly changed to incorporate the new face (Experiment 2). Participants rated morphs between their own and the newly-associated according to how similar they were to the self, before and after performing the perceptual matching task. Changes to the conceptual self did not have an effect on the bodily self-representation. These results suggest that modulatory links between aspects of the mental self-representation, when focused on the non-social self, are unidirectional and flow in a bottom-up manner.

Intimate imitation: Automatic motor imitation in romantic relationships.

Our relationships with romantic partners are often some of the closest and most important relationships that we experience in our adult lives. Interpersonal closeness in romantic relationships is characterised by an increased overlap between cognitive representations of oneself and one's partner. Importantly, this type of self-other overlap also occurs in the bodily domain, whereby we can represent another's embodied experiences in the same way as we represent our own. However, as yet this bodily self-other overlap has only been investigated in individuals unfamiliar to each other. Here, we investigate bodily self-other overlap between romantic partners, using automatic imitation as an example case of bodily overlap in the motor domain. We found that participants automatically imitated romantic partners significantly more than close others with whom they had a platonic relationship. Furthermore, imitation in these relationships was related to key aspects of relationship quality, as indicated by adult attachment style.

Attending to the bodily self.

Humphreys and Sui provide a powerful theoretical framework to explain processing biases toward self-related information. However, the framework is primarily applied to information relevant to a conceptual self-representation. Here, we show a similar processing bias for information related to the bodily self, grounded in sensorimotor representations. Furthermore, we can use bodily illusions to explore the ways in which embodied self-associations can affect our perceptual and attentional processing. It is possible to extend the current framework to take into account these effects, and we argue that this will yield considerable benefits for our understanding of self-relevance.

Heartfelt empathy? No association between interoceptive awareness, questionnaire measures of empathy, reading the mind in the eyes task or the director task.

Interoception, defined as afferent information arising from within the body, is the basis of all emotional experience and underpins the 'self.' However, people vary in the extent to which interoceptive signals reach awareness. This trait modulates both their experience of emotion and their ability to distinguish 'self' from 'other' in multisensory contexts. The experience of emotion and the degree of self/other distinction or overlap are similarly fundamental to empathy, which is an umbrella term comprising affect sharing, empathic concern and perspective-taking (PT). A link has therefore often been assumed between interoceptive awareness (IA) and empathy despite a lack of clear evidence. To test the hypothesis that individual differences in both traits should correlate, we measured IA in four experiments, using a well-validated heartbeat perception task, and compared this with scores on several tests that relate to various aspects of empathy. We firstly measured scores on the Index of Interpersonal Reactivity and secondly on the Questionnaire of Cognitive and Affective Empathy. Thirdly, because the 'simulationist' account assumes that affect sharing is involved in recognizing emotion, we employed the 'Reading the Mind in the Eyes Task' for the recognition of facial expressions. Contrary to expectation, we found no significant relationships between IA and any aspect of these measures. This striking lack of direct links has important consequences for hypotheses about the extent to which empathy is necessarily embodied. Finally, to assess cognitive PT ability, which specifically requires self/other distinction, we used the 'Director Task' but found no relationship. We conclude that the abilities that make up empathy are potentially related to IA in a variety of conflicting ways, such that a direct association between IA and various components of empathy has yet to be established.

Your place or mine: shared sensory experiences elicit a remapping of peripersonal space.

Our perceptual systems integrate multisensory information about objects that are close to our bodies, which allow us to respond quickly and appropriately to potential threats, as well as act upon and manipulate useful tools. Intriguingly, the representation of this area close to our body, known as the multisensory 'peripersonal space' (PPS), can expand or contract during social interactions. However, it is not yet known how different social interactions can alter the representation of PPS. In particular, shared sensory experiences, such as those elicited by bodily illusions such as the enfacement illusion, can induce feelings of ownership over the other's body which has also been shown to increase the remapping of the other's sensory experiences onto our own bodies. The current study investigated whether such shared sensory experiences between two people induced by the enfacement illusion could alter the way PPS was represented, and whether this alteration could be best described as an expansion of one's own PPS towards the other or a remapping of the other's PPS onto one's own. An audio-tactile integration task allowed us to measure the extent of the PPS before and after a shared sensory experience with a confederate. Our results showed a clear increase in audio-tactile integration in the space close to the confederate's body after the shared experience. Importantly, this increase did not extend across the space between participant and confederate, as would be expected if the participant's PPS had expanded. Thus, the pattern of results is more consistent with a partial remapping of the confederate's PPS onto the participant's own PPS. These results have important consequences for our understanding of interpersonal space during different kinds of social interactions.

Changing bodies changes minds: owning another body affects social cognition.

Research on stereotypes demonstrates how existing prejudice affects the way we process outgroups. Recent studies have considered whether it is possible to change our implicit social bias by experimentally changing the relationship between the self and outgroups. In a number of experimental studies, participants have been exposed to bodily illusions that induced ownership over a body different to their own with respect to gender, age, or race. Ownership of an outgroup body has been found to be associated with a significant reduction in implicit biases against that outgroup. We propose that these changes occur via a process of self association that first takes place in the physical, bodily domain as an increase in perceived physical similarity between self and outgroup member. This self association then extends to the conceptual domain, leading to a generalization of positive self-like associations to the outgroup.

Change my body, change my mind: the effects of illusory ownership of an outgroup hand on implicit attitudes toward that outgroup.

The effect of multisensory-induced changes on body-ownership and self-awareness using bodily illusions has been well established. More recently, experimental manipulation of bodily illusions have been combined with social cognition tasks to investigate whether changes in body-ownership can in turn change the way we perceive others. For example, experiencing ownership over a dark-skin rubber hand reduces implicit bias against dark-skin groups. Several studies have also shown that processing of skin color and facial features play an important role in judgements of racial typicality and racial categorization independently and in an additive manner. The present study aimed at examining whether using multisensory stimulation to induce feelings of body-ownership over a dark-skin rubber hand would lead to an increase in positive attitudes toward black faces. We here show, that the induced ownership of a body-part of a different skin color affected the participants' implicit attitudes when processing facial features, in addition to the processing of skin color shown previously. Furthermore, when the levels of pre-existing attitudes toward black people were taken into account, the effect of the rubber hand illusion on the post-stimulation implicit attitudes was only significant for those participants who had a negative initial attitude toward black people, with no significant effects found for those who had positive initial attitudes toward black people. Taken together, our findings corroborate the hypothesis that the representation of the self and its relation to others, as given to us by body-related multisensory processing, is critical in maintaining but also in changing social attitudes.

My face, my heart: cultural differences in integrated bodily self-awareness.

Body-awareness is produced by an integration of both interoceptive and exteroceptive bodily signals. However, previous investigations into cultural differences in bodily self-awareness have only studied these two aspects in isolation. We investigated the interaction between interoceptive and exteroceptive self-processing in East Asian and Western participants. During an interoceptive awareness task, self-face observation improved performance of those with initially low awareness in the Western group, but did not benefit the East Asian participants. These results suggest that the integrated, coherent experience of the body differs between East Asian and Western cultures. For Western participants, viewing one's own face may activate a bodily self-awareness which enhances processing of other bodily information, such as interoceptive signals. Instead, for East Asian individuals, the external appearance of the self may activate higher-level, social aspects of self-identity, reflecting the importance of the sociocultural construct of "face" in East Asian cultures.

Executive functions are employed to process episodic and relational memories in children with autism spectrum disorders.

OBJECTIVE: Long-term memory functioning in autism spectrum disorders (ASDs) is marked by a characteristic pattern of impairments and strengths. Individuals with ASD show impairment in memory tasks that require the processing of relational and contextual information, but spared performance on tasks requiring more item-based, acontextual processing. Two experiments investigated the cognitive mechanisms underlying this memory profile. METHOD: A sample of 14 children with a diagnosis of high-functioning ASD (age: M = 12.2 years), and a matched control group of 14 typically developing (TD) children (age: M = 12.1 years), participated in a range of behavioral memory tasks in which we measured both relational and item-based memory abilities. They also completed a battery of executive function measures. RESULTS: The ASD group showed specific deficits in relational memory, but spared or superior performance in item-based memory, across all tasks. Importantly, for ASD children, executive ability was significantly correlated with relational memory but not with item-based memory. No such relationship was present in the control group. This suggests that children with ASD atypically employed effortful, executive strategies to retrieve relational (but not item-specific) information, whereas TD children appeared to use more automatic processes. CONCLUSIONS: The relational memory impairment in ASD may result from a specific impairment in automatic associative retrieval processes with an increased reliance on effortful and strategic retrieval processes. Our findings allow specific neural predictions to be made regarding the interactive functioning of the hippocampus, prefrontal cortex, and posterior parietal cortex in ASD as a neural network supporting relational memory processing.

More of myself: manipulating interoceptive awareness by heightened attention to bodily and narrative aspects of the self.

Psychology distinguishes between a bodily and a narrative self. Within neuroscience, models of the bodily self are based on exteroceptive sensorimotor processes or on the integration of interoceptive sensations. Recent research has revealed interactions between interoceptive and exteroceptive processing of self-related information, for example that mirror self-observation can improve interoceptive awareness. Using heartbeat perception, we measured the effect on interoceptive awareness of two experimental manipulations, designed to heighten attention to bodily and narrative aspects of the self. Participants gazed at a photograph of their own face or at self-relevant words. In both experimental conditions interoceptive awareness was significantly increased, compared to baseline. Results show that attention to narrative aspects of self, previously regarded as relying on higher-order processes, has an effect similar to self-face stimuli in improving interoceptive awareness. Our findings extend the previously observed interaction between the bodily self and interoception to more abstract amodal representations of the self.

Experiencing ownership over a dark-skinned body reduces implicit racial bias.

Previous studies have investigated how existing social attitudes towards other races affect the way we 'share' their bodily experiences, for example in empathy for pain, and sensorimotor mapping. Here, we ask whether it is possible to alter implicit racial attitudes by experimentally increasing self-other bodily overlap. Employing a bodily illusion known as the 'Rubber Hand Illusion', we delivered multisensory stimulation to light-skinned Caucasian participants to induce the feeling that a dark-skinned hand belonged to them. We then measured whether this could change their implicit racial biases against people with dark skin. Across two experiments, the more intense the participants' illusion of ownership over the dark-skinned rubber hand, the more positive their implicit racial attitudes became. Importantly, it was not the pattern of multisensory stimulation per se, but rather, it was the change in the subjective experience of body ownership that altered implicit attitudes. These findings suggest that inducing an overlap between the bodies of self and other through illusory ownership is an effective way to change and reduce negative implicit attitudes towards outgroups.

Mirror-touch synaesthesia changes representations of self-identity.

Individuals with mirror-touch synaesthesia (MTS) experience touch on their own bodies when observing another person being touched. Whilst somatosensory processing in MTS has been extensively investigated, the extent to which the remapping of observed touch on the synaesthete's body can also lead to changes in the mental representation of the self remains unknown. We adapted the experimental paradigm of the 'enfacement illusion' to quantify the changes in self-face recognition as a result of synaesthetic touch. MTS and control participants observed the face of an unfamiliar person being touched or not, without delivering touch on the participant's face. Changes in self-representation were quantified with a self-face recognition task, using 'morphed' images containing varying proportions of the participant's face and the face of the unfamiliar other. This task was administered before and after the exposure to the other face. While self-recognition performance for both groups was similar during pre-test, MTS individuals showed a significant change in self-recognition performance following the observation of touch delivered to the other face. Specifically, the images that participants had initially perceived as containing equal quantities of self and other became more likely to be recognised as the self after viewing the other being touched. These results suggest that observing touch on others not only elicits a conscious experience of touch in MTS, but also elicits a change in the mental representation of the self, blurring self-other boundaries. This is consistent with a multisensory account of the self, whereby integrated multisensory experiences maintain or update self-representations.

I feel your fear: shared touch between faces facilitates recognition of fearful facial expressions.

Embodied simulation accounts of emotion recognition claim that we vicariously activate somatosensory representations to simulate, and eventually understand, how others feel. Interestingly, mirror-touch synesthetes, who experience touch when observing others being touched, show both enhanced somatosensory simulation and superior recognition of emotional facial expressions. We employed synchronous visuotactile stimulation to experimentally induce a similar experience of "mirror touch" in nonsynesthetic participants. Seeing someone else's face being touched at the same time as one's own face results in the "enfacement illusion," which has been previously shown to blur self-other boundaries. We demonstrate that the enfacement illusion also facilitates emotion recognition, and, importantly, this facilitatory effect is specific to fearful facial expressions. Shared synchronous multisensory experiences may experimentally facilitate somatosensory simulation mechanisms involved in the recognition of fearful emotional expressions.