The surprising ways the body works with the brain to shape our sense of self

On a bitingly cold winter’s day in 2013, a woman whom I’ll call Laurie took me to the terrace of a tall building in a city about two hours west of London, England. Years earlier, she’d tried to jump from the terrace and kill herself.

It had been a harrowing time for Laurie. She’d started hearing voices in her head and often felt as if an outside force was controlling her. She attributed her suicide attempt to this outside force. “I wasn’t the one making that decision,” she told me. “Someone was trying to push me off the edge.”

Fortunately, she never did jump. A man standing below saw her and called out to her, and the police arrived shortly after to help her off the ledge. And by the time we met, Laurie had been diagnosed with schizophrenia.

We tend to think of schizophrenia as a disorder of the mind. But conditions like schizophrenia, Alzheimer’s and autism also disturb the way that people relate to their bodies, as I found while researching my book The Man Who Wasn’t There: Investigations into the Strange New Science of Self. The neurocognitive mechanisms behind those disturbances can tell us a lot about how our brains and our bodies work together to produce our sense of self. Understanding this relationship has profound implications—both for how we can remain healthy, and how we can help people whose suffering results from a disruption of our tightly interwoven physical and psychological selves.

In Laurie’s case, she remembers feeling dissociated from her body when her symptoms were at their most intense.

“If I [would] extend my hand out, I’d think my hand was going to go off somewhere else, further away,” she said.

Understanding the bodily self

What Laurie was experiencing was a disruption of her bodily self as well as her psychological one. German philosopher Thomas Metzinger has argued that the feeling of being embodied is a pre-reflective, pre-linguistic form of selfhood—a sense that our ancestors must have had long before humans gained the capacity to use the personal pronoun in phrases like “I think.” There is no narrative in this kind of bodily self; just the ability to feel anchored in a body and distinguish between the self and the non-self.

Eventually, evolution gave us memory, cognition, culture and the ability to construct narratives. All of this has allowed us to form a psychological self that works in conjunction with our bodily one.

In order to create a bodily self, the brain has to make maps of the body. Our somatosensory cortex, for example, creates maps representing different parts of the body: one region for the face, and another region for the right foot, and so on. This gives us a way to localize our sense of touch. Then there are so-called proprioceptive maps that allow us to have a sense of our bodies in three-dimensional space. That’s how, if you close your eyes and visualize your body, you will know, sight unseen, how your arms, legs and the rest of your body are positioned. Such maps enable the brain to efficiently control the body, keep it in physiological equilibrium and ensure its survival.

But these are not static representations. The brain is constantly updating its maps of the body. It does it every time you scratch your nose or move your arm. The brain’s maps also incorporate slower changes. For example, a pregnant woman’s sense of her own body changes during the course of the pregnancy. Both external sensations (when she looks at herself in the mirror) and internal sensations (via her skin, muscles and joints) are integrated by her brain to create a sense of her changing bodily self. When everything is working according to plan, our perception is in tune with physical reality.

Foreign limbs

But occasionally, things can go wrong—either in the pathways that are providing information to the brain, or in the map-making circuitry in the brain. This is what leads to disturbances of the bodily self. The consequences can be debilitating, as exemplified by a rare condition called body integrity identity disorder (BIID).

People with BIID have the feeling that some part of their body is not their own. (The disorder is also known as xenomelia, from the Greek words for “foreign” and “limb.”) Some neuroscientists believe that this disorder is due to erroneous body maps in the brain. A person with BIID feels a mismatch between her body as she subjectively experiences it and her physical body. The subjective perception tends to win out, sometimes prompting sufferers to seek out voluntary amputations in order to find equilibrium.

BIID is an old ailment. Peter Brugger, head of neuropsychology at University Hospital of Zurich in Switzerland, writes in one paper about an unusual case in the late 18th century. An Englishman forced a surgeon in France to amputate his leg at gunpoint. Upon his return to England, the man sent the surgeon 250 guineas, along with a note of thanks saying that the leg had been “an invincible obstacle” to his happiness.

There’s some evidence of neurological changes in the brains of people suffering from BIID. For example, Brugger’s team has shown that the right superior parietal lobule—a brain region vital for constructing body maps—is thinner in BIID patients. And neuroscientist V. S. Ramachandran of the University of California at San Diego and his colleagues have shown that BIID sufferers exhibit different neural activity in this brain region.

It should be emphasized that these scans do not mean that differences in the brain are causing BIID. It could be that patients’ brains show differences because they have spent a lifetime obsessing that a body part does not belong to them. This latter scenario would point to a psychological, rather than neurological, origin for BIID. But what is clear is that the suffering experienced by people with BIID is real. The condition can cause them to focus attention on the “foreign” limb to the exclusion of much else in their lives, leading to isolation and depression as well as voluntary amputation in some cases. In this way, BIID illustrates rather dramatically how a perturbed self-image can impact how we live our lives in profound ways.

While BIID is a clear disturbance of the bodily self, the role of the body is less obvious—though likely equally important—in other conditions. Autism is a case in point.

Autism and the bodily self

Children suffering from autism are often diagnosed based on certain behaviors. They may have trouble relating to others and forming bonds with other children. They also tend have problems with theory of mind—the instinctive ability that allows people to infer what someone else is thinking based on cues from their actions, body language, and tone of voice.

Preliminary evidence suggests that autism also affects people’s ability to sense their own body and physical states. One of the earliest studies to demonstrate this was done by psychologist Russell Hurlburt and colleagues in the United Kingdom in the early 1990s. They asked three adults with Asperger’s to carry a beeper (PDF) that would beep at random. Any time the beeper went off, the study subjects had to write down their thoughts and inner experiences. The study showed that the subjects’ reports lacked clear perceptions of inner feelings, which would nearly always be found in similar reports by neurotypicals.

This suggests that autism, often considered a mental condition, may be associated with a disruption of the bodily self. Helping children with autism learn to better feel and perceive their bodies as their bodies interact with the environment could help ease their behavioral problems.

One of the most widely used methods to achieve this goal is called occupation therapy using sensory integration (OT/SI). Rigorous, large-scale, double-blind studies–which are extremely hard to carry out–have yet to unequivocally establish the efficacy of such therapies. But there’s growing scientific evidence that they work.

These therapies require children to engage in activities that force their brains to process and integrate external and internal bodily sensations—in essence, creating a better perception of their own bodies in relation to the environment.

The activities have to be tailored to each child’s specific needs. For instance, one recent study of 17 children used a novel technique. A child had to lie down prone on a carpeted scooter board and pull himself or herself up a ramp, turn it around, and ride down the ramp to land in a cushioned area of mats and pillows with different textures. The study found that 30 sessions of OT/SI significantly and positively influenced the children’s ability to socialize.

“In this activity, the child is experiencing total body tactile and proprioceptive sensations (from scooter board texture, actively moving muscles against resistance, and landing in textured mats and pillows) to increase body awareness and using this enhanced sensory input to plan body movements during the scooter board activity,” the authors write. Such neural processes of sensory integration, which are crucial to forming a bodily self, “serve as foundations for an individual’s perceptions, behaviors and learning,” according to a 2011 study published in Adolescent Psychiatry.

Recovering our identities

Meanwhile, disorders like Alzheimer’s disease are changing the way that we understand even our narrative, or psychological, selves. Our narrative selves are composed of the stories we tell ourselves and others about who we are, drawn from our long-term memories. We are composed of not just one narrative self but many. Imagine, for a moment, the difference between the way you feel around your mother and the way you feel around colleagues at work. The memories, thoughts and feelings that come to the fore in each context are different, creating a somewhat different narrative self, and influencing how that narrative grows.

Some philosophers have argued that our sense of self is entirely dependent on such narratives. Take them away, and nothing’s left. But Alzheimer’s disease challenges such notions.

The reason we find Alzheimer’s so terrifying is that it destroys our ability to form new long-term memories and eventually eats away at older ones. In effect, it shreds our narrative self. But some researchers believe that a pre-cognitive, pre-reflective form of selfhood persists in Alzheimer’s patients—even in the face of severe cognitive decline.

Pia Kontos, a sociologist at the University of Toronto who works on the rehabilitation of the elderly, has seen examples of such “embodied selfhood” in her studies of long-term care facilities for people with Alzheimer’s disease. One particular observation left a deep impression on her. Kontos met an elderly male resident who was severely cognitively impaired. He spoke only in single words that were often nonsensical.

On Simchat Torah, a Jewish high holiday to celebrate the Torah, the residents went to the synagogue in the long-term care home. The old man stood in line, waiting to be called to the bimah (pulpit) to sing the prayer.

“I saw this gentleman get up in the lineup, and I remember my whole body clutched,” Kontos told me. “This is going to be a disaster, I thought, because he can’t put two words together.”

What followed stunned her. When his name was called out, the man confidently walked up to the bimah and recited the prayer with utter proficiency.

Kontos, inspired by the work of French philosopher Maurice Merleau-Ponty and French sociologist Pierre Bourdieu, thinks that what the elderly gentleman showed that day was an instance of embodied selfhood. This aspect of his self was activated by the “touch of the Torah, the presence of the rabbi, the presence of all the congregants,” she said. It’s a clear demonstration of the body’s role–in close concert with the brain–in shaping our narrative self.

All this isn’t to imply that our sense of self is layered like an onion, with a bodily self at the core. Rather, our bodily selves influence our narrative selves, and vice versa. Our bodies and our brains are inextricably linked.

This piece is adapted from and uses research conducted for Anil Ananthaswamy’s book The Man Who Wasn’t There: Investigations into the Strange New Science of the Self. We welcome your comments at ideas@qz.com.

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