The Strange World of Mirror Touch Synaesthesia
An amazing rare condition
Imagine watching someone gently pat their shoulder and feeling the same sensation on your own shoulder.
This is the reality for individuals with mirror-touch synaesthesia, a rare and fascinating neurological condition where observing touch to another person induces a tactile sensation on the synaesthetes own body.
I am fascinated by this strange condition, and have been exploring its prevalence, neurocognitive mechanisms, and the profound impact it has on those who experience it.
Understanding Mirror-Touch Synaesthesia
It’s a condition where individuals experience tactile sensations on their own body simply by observing touch to another person. For instance, if a synaesthete sees someone being touched on the cheek, they might feel a similar touch on their own cheek.
This phenomenon is akin to the brain creating a mirror image of the sensory experiences witnessed, hence the name “mirror-touch” synesthesia. How strange!.
Prevalence and characteristics
Despite its rarity, mirror-touch synesthesia is one of the more common types of synaesthesia, with a prevalence rate of approximately 1.6% to 2.5% of the general population. This condition can manifest in various ways, with some individuals experiencing intense physical responses to any observed touch, while others feel a milder “echo” of the touch.
The sensations can be felt in the same part of the body as the observed touch (specular correspondence) or in the opposite part (anatomical correspondence.
The neurocognitive mechanisms — how it works
The neurocognitive mechanisms underlying mirror-touch synaesthesia involve heightened activity in neural systems that are typically activated when observing touch to others.
Research suggests that the condition relies on the activation of somatosensory representations within the human mirror-touch system, which are also engaged when non-synaesthetic individuals observe another person being touched.
So the same response is present in non-affected people, it’s just that the effect is not so obvious or gets suppressed, but that effect is amplified and expressed in those affected by the condition, and this increased cortical activity within the somatosensory mirror system is believed to be a key factor in the synaesthetic experience.
The link to empathy
I found that one of the most intriguing aspects of mirror-touch synaesthesia is its link to empathy. Studies have shown that mirror-touch synaesthetes tend to have higher levels of affective and pain empathy compared to non-synaesthetes. This heightened empathy is thought to be a result of the enhanced activation of mirror systems in the brain, which are involved in simulating the experiences of others.
However, it is important to note that while emotional reactivity is elevated, cognitive empathy and social skills may not necessarily be higher in mirror-touch synaesthetes.
The impact on self-identity
The condition can also influence an individual’s sense of self, and research has demonstrated that observing touch can induce measurable changes in the stored self-face representations of mirror-touch synaesthetes.
This phenomenon, known as the “Enfacement Illusion,” suggests that the synaesthetic experience of touch can blur the boundaries between self and other, leading to changes in self-recognition and self-representation.
I find this part of the research a bit airy-fairy, and am not entirely convinced the conclusion is totally convincing. However, this blurring of self-other boundaries is consistent with a multisensory account of the self, where integrated multisensory experiences maintain or update self-representations.
How Mirror-Touch Synaesthesia was tested
To confirm the presence of mirror-touch synaesthesia, researchers typically use sensory interference tasks. In these tasks, participants are touched on specific body parts while observing an assistant being touched. The participants are then asked to report where they feel the sensation.
A higher rate of errors in synaesthetic subjects compared to non-synaesthetic controls is expected, indicating the presence of synaesthetic touch.
Theories and hypotheses
Several theories have been proposed to explain the mechanisms behind this phenomena. One theory suggests that the condition is mediated by the anterior insula, which is involved in the conscious perception of touch and self-processing. Another theory posits that the visual and somatosensory systems in mirror-touch synaesthetes are directly connected, leading to the experience.
A third theory involves bimodal cells in the parietal cortex, which are activated above a certain threshold when observing touch.
A link to Autism?
Interestingly, mirror-touch synaesthesia may co-occur with autism spectrum disorders. Some studies have suggested that individuals with autism may be more likely to experience synaesthetic phenomena, including this type of synaesthesia.
This co-occurrence could be related to the heightened sensory sensitivities and differences in neural processing observed in autism.
By experiencing the physical sensations of others as if they were their own, mirror-touch synaesthetes provide valuable insights into the neural mechanisms underlying social cognition and self-other representation.
As research continues to unravel the mysteries of this condition, it helps us gain a deeper understanding of the intricate ways in which our brains process and interpret the world around us.
References:
Mirror-touch synaesthesia: the role of shared representations in social cognition (ucl.ac.uk)
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