Summary: A psychological replication study established an empirical link between a person’s abstract psychological identity and their physical, bodily awareness. The research utilizes the classic “rubber hand illusion” to demonstrate that individuals with a fragile, less coherent sense of self possess a highly malleable physical boundary.
These findings provide solid experimental evidence for the framework of “embodied cognition”, the deep connection between the mind’s self-concept and physical bodily awareness, while opening up targeted clinical pathways to treat psychiatric conditions like borderline personality disorder.
Key Facts
- The Embodied Connection: Psychological perceptions of identity and how individuals physically experience their own bodies are deeply intertwined. A weaker, less stable psychological sense of self directly correlates with a lower baseline of fundamental bodily awareness.
- The Rubber Hand Framework: Replicating and confirming a previous pilot study, researchers evaluated 77 participants aged 18–40 using the “rubber hand illusion”. In the experiment, a subject’s real hand is hidden behind a screen while a gloved rubber hand is placed in plain view. Researchers then stroke both the hidden real hand and the visible fake hand with a paintbrush either in synchronous or asynchronous rhythms.
- The Asynchronous Mismatch: While standard subjects typically only trick themselves into feeling ownership of the fake hand when the strokes are synchronized, individuals with low self-concept clarity experienced acute sensory confusion even when the brush strokes were completely out of synch.
- The Malleable Self-Concept: Participants most vulnerable to the illusion scored significantly lower on psychological scales measuring the clarity, coherence, and stability of their identity. Senior author Dr. Jennifer Bartz notes that these individuals possess a highly malleable bodily self, making them unusually vulnerable to incorporating external objects from the environment into their personal sense of identity.
- Empirical Proof for Theory: While the evolutionary framework of embodied cognition is highly intuitive, it has historically lacked rigorous empirical, experimental testing. This study provides a concrete experimental foundation proving that psychological self-concept and physical perception go hand in hand.
- Clinical Applications for BPD: Unmasking this somatic flexibility raises important clinical questions regarding empathy and psychiatric treatment. Understanding that a fragmented psychological identity directly warps physical, spatial awareness gives clinicians a new bodily toolkit to support individuals living with borderline personality disorder.
Source: McGill University
People who have a weaker sense of self are also more likely to have less bodily awareness, McGill researchers have found. The study supports the idea that people’s perceptions of themselves and how they experience their own bodies are deeply connected.
Beyond deepening psychologists’ understanding of “embodied cognition,” the connection between our minds and our fundamental bodily awareness, the findings could have concrete applications regarding the treatment of certain psychiatric conditions, the researchers said.
A more malleable self?
This study replicated and confirmed the results of a smaller study previously led by Sonia A. Krol, who is also a co-author of the current study. It involved 77 participants ages 18-40 from the McGill community, who were subjected to a commonly used device in psychological research called the “rubber hand illusion.”
One of a participant’s hands was hidden behind a screen, while a rubber hand was placed in view. Both the subject’s hand and the fake hand were wearing a glove to hide any differences in skin tone. Researchers then used a paintbrush to stroke the hand of the subject and the fake hand in two different ways: in synch and out of synch.
While it was expected that subjects would report feeling like the rubber hand was theirs when the hands were stroked simultaneously – and this was generally the case – some people also experienced confusion when the strokes were not simultaneous, said Jennifer Bartz, senior author of the study, Professor in the Department of Psychology, and Director of the McGill Laboratory of Attachment and Prosociality.
The participants who were more vulnerable to the illusion tended, in the accompanying questionnaire, to score lower on a scale measuring the clarity, coherence and stability of their sense of self.
“This really suggests that they maybe have a more malleable kind of bodily self, where they’re more vulnerable to incorporating other things in the environment into their sense of self, even when most people wouldn’t be vulnerable to that,” said Bartz.
How two understandings of the self go ‘hand in hand’
Embodied cognition makes sense from an evolutionary standpoint but has not often been researched in an empirical way, said Willis Klein, lead author of the study and PhD candidate in the Department of Psychology.
“To be able to take this beautiful theoretical framework and to say, here’s experimental evidence for this quite intuitive perspective on what the mind is, it’s just amazing,” he added.
The researchers said the results raise interesting questions for future research, such as how embodied cognition can play out in processes like empathy, or how clinicians can better help people presenting with a less stable sense of self, such as individuals living with borderline personality disorder.
Funding:
This research was supported by the Natural Sciences and Engineering Research Council and the Fonds de Recherche du Québec – Société et Culture.
Key Questions Answered:
A: Because your psychological mind and physical body are not separate systems; they are deeply locked into a loop called embodied cognition. McGill’s research demonstrates that if your mental self-concept lacks clarity, coherence, and stability, your brain naturally treats your physical body boundaries as highly flexible. This makes you far more likely to misinterpret sensory feedback from the physical world.
A: It is a visual and tactile trick. A participant’s real hand is hidden while a fake rubber hand is stroked with a paintbrush in perfect sync with their real flesh. For most people, the brain gets confused by seeing a fake hand stroked while feeling identical sensations, causing them to adopt the rubber hand as their own. However, people with a weak sense of self are so somatically flexible that their brains try to absorb the fake hand even when the brush strokes are completely out of time.
A: It gives therapists a direct physical doorway to treat an abstract mental issue. Individuals living with borderline personality disorder frequently suffer from a highly unstable, fragmented sense of internal self. Now that science has proved this identity fragmentation directly causes a porous physical boundary, clinicians can develop targeted physical therapies to help patients stabilize their bodily awareness, helping them anchor both their physical and psychological selves.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this neuroscience research news
Author: Aurelie Boucher
Source: McGill University
Contact: Aurelie Boucher – McGill University
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Self-concept clarity and interoceptive updating in the rubber-hand illusion: A double replication study” by Klein, W., Gregory, A. J., Krol, S. A., & Bartz, J. A. Canadian Journal of Experimental Psychology
DOI:10.1037/cep0000387
Abstract
Self-concept clarity and interoceptive updating in the rubber-hand illusion: A double replication study
Prediction error minimization and embodied cognition theorists posit that abstract self-representations are predicated on models of the self as an embodied agent. While the view of continuity between conceptual and bodily self is common to several frameworks in psychology and cognitive science, empirical tests of this relationship are scant.
However, a recent study by Krol et al., (see record 2020-26839-011) found that people low in self-concept clarity (SCC) were more vulnerable to the rubber-hand illusion—in particular, in the asynchronous stroking condition, where the illusion is unwarranted.
This study provides preliminary evidence for an association between self-concept strength and vulnerability to illusions regarding the bodily self. Here we sought to replicate this finding in an existing study that assessed SCC and the rubber-hand illusion.
Using linear mixed-effects modelling, we found that lower SCC was again associated with greater embodiment of the rubber hand in the asynchronous condition; moreover, we also observed this effect in the synchronous stroking condition, providing additional evidence for the role of SCC in vulnerability to bodily illusions.
We discuss the implications of this finding for theories in social cognitive neuroscience. Finally, as the study we drew upon to test the replication effect involved the administration of intranasal oxytocin, we also took this opportunity to replicate a previously observed effect of oxytocin on embodiment of the rubber hand; this effect, however, did not replicate, although methodological difference may have played a role.
