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In another version, we found this uniqueness effect of memories was stronger when we gave our first hamster a name, suggesting that it really does have something to do with identity. It’s remarkable how naming an animal confers a new sense of identity, which is why you should not name your livestock if you intend to eat your animals. The uniqueness and identity conferred by names may also explain why young children are often affronted when they first learn that they share their name with another child.

We think our findings show that children begin to appreciate how minds and memories, in particular, create the unique individual. Earlier, we saw there is an increasing awareness of other people’s mental states from four years of age as shown by the ‘theory of mind’ research. Initially, young children appreciate that other people have minds. As they develop, children come to increasingly appreciate the importance of their mind and the contents of their mind as being different to others and unique.

By the time we are adults, most of us think that our autobiographical memories are crucial to our sense of self. Our bodies could be copied but not our memories. Our memories are what make us who we are. Aside from the science fiction movies we have already discussed, anyone unfortunate in real life to witness the decline of a loved one with rapidly progressing dementia, which destroys memory, knows how the person’s identity and sense of self can unravel. That loss of identity is one of the reasons why memory failure is considered such a traumatizing symptom for relatives because the sufferer no longer recognizes those around him.

Once again, neurologist Oliver Sacks reminds us how we rely on others to create our sense of self-identity. One of his patients, a former grocer called William Thompson, had Korsakoff’s syndrome, that produced a profound amnesia so he was unable to remember anything for more than a second or two – just like Clive Wearing who we encountered earlier. He lived in the eternal present and was unable to generate a stable sense of self. In one exchange, Sacks walked on to the ward in a white coat to see William who greeted him:

‘What’ll it be today?’ he says, rubbing his hands. ‘Half a pound of Virginia, a nice piece of Nova?’

(Evidently he saw me as a customer – he often would pick up the phone on the ward, and say ‘Thompson’s Delicatessen.’)

‘Oh Mr. Thompson!’ I exclaim. ‘And who do you think I am?’

‘Good heavens, the light’s bad – I took you for a customer. As if it isn’t my old friend Tom Pitkins … Me and Tom’ (he whispers in an aside to the nurse) ‘was always going to the races together.’

‘Mr. Thompson, you are mistaken again.’

‘So I am,’ he rejoins, not put out for one moment. ‘Why would you be wearing a white coat if you were Tom? You’re Hymie, the kosher butcher next door. No bloodstains on your coat though. Business bad today? You’ll look like a slaughterhouse by the end of the week.’13

It was if William reeled effortlessly from one self-reflected identity to the next depending on who he thought Sacks was. He was oblivious to his circumstances. He had no awareness that he was a Korsakoff’s patient in a psychiatric hospital but rather, as Sacks put it, had to ‘literally make himself (and his world) up every moment’. Unlike the woman with Tourette’s Syndrome who could not stop incorporating the mannerisms of others, William used the identity of those around him in order to create his own identity.

Being in Two Minds

Constructing a plausible story is known as confabulation and found in various forms of dementia as the patient attempts to make sense of their circumstances. Remember TH who could not recognize himself in the mirror and thought his reflection belonged to his neighbour who had snuck into the house? However, we can all confabulate to some extent even though we are not aware we are doing this. These produce the biases, selective interpretations, reframing and cognitive dissonance processes in which we are less objective than usual. We are all naturally inclined to interpret the world in terms of meaningful stories and this probably reflects the activity of a system known as the ‘interpreter’ which appears to be localized to the left hemisphere.14

We are not aware of this system normally as our brain processes are effortlessly and invisibly integrated below our levels of awareness. We simply experience the output of the interpreter as our conscious appraisal of our situations, our thoughts and our behaviours. After all, we are our minds and if that is largely constructed by unconscious processes why should we ever become aware of the so-called interpreter? However, the activity of the interpreter was revealed by neuroscientist Michael Gazzaniga in his research on split-brain patients.

The normal brain is really a tale of two cities on the left and the right. Gazzaniga demonstrated that you could reveal the autonomy of the two hemispheres by selectively feeding different information to each. To do this, he presented words and images on the left and right side of a computer screen while the patient stared at a spot in the middle. This ensured that each hemisphere processed stimuli on the opposite side and because they were no longer connected to each other through the corpus callosum, there was no exchange of information. For example, if the words ‘Key’ and ‘Ring’ were briefly flashed in the left and right halves of the screen respectively, the patient reported seeing the word ‘Ring’ because this was processed by the opposite left hemisphere that controls language. However, if the patient was asked to choose the corresponding object from a selection on the table, they would pick up a key with the left hand that was controlled by the right hemisphere. Experiment after experiment revealed that the two hemispheres were functioning independently of each other. In one study, a naked man was flashed into the right hemisphere causing the female patient to laugh but not be able to say what it was she was finding amusing. Her left hemisphere was unaware of the naked man and so could not explain what was amusing.

Sometimes, however, the patients make up a story to make sense of their unconscious activity. In one classic example told by Gazzaniga, one of his split-brain patients, Paul, was shown a snow scene in this left visual field and a picture of a chicken foot in his right visual field, and asked to choose the correct image from a selection on the table. He picked out a picture of a shovel with his left hand and a picture of the chicken foot with his right. When his attention was drawn to the discrepancy, and he was asked why he had chosen two different images, Paul replied, ‘Oh that’s simple, the chicken claw goes with the chicken, and you need the shovel to clean out the chicken shit!’

Gazzaniga has proposed that there are not two separate minds or selves in these spilt-brain patients. Rather, the mind is a product of the mental processes of the brain that are shared across the two hemispheres. Language has the advantage of providing the narrative output, so the interpreter in the left hemisphere is able to articulate a coherent account to integrate the different pieces of information. Normally theses processes are a collaborative effort with information streaming in from all the different processing regions. But in the spilt-brain patient there is no shared communication is possible. Presented with the choices of the right hemisphere that are inconsistent with the information in the left, the interpreter reconciles the difference with a plausible story.

What the split-brain studies reveal is that the self illusion is really the culmination of a multitude of processes. These usually work together in synchrony to produce a unified self but when inconsistencies arise, the system, strongly influenced by language, works to re-establish coherence. Probably one of the most compelling examples of this process comes from a personal anecdote that Gazzaniga15 tells that comes from the late Mark Rayport, a neurosurgeon from Ohio. During one operation on a patient in which Rayport was stimulating the olfactory bulb, the brain region associated with smell, the patient reported experiencing different aromas depending on the context. When the patient was asked to reminisce about a happy time in his life, stimulation of the region produced the sensation of roses. Rayport then asked the patient to think about a bad time in his life. This time stimulation of the same cluster of neurons produced the sensation of rotten eggs! This anecdote suggests that the neural networks of the brain store associations that fit together into a coherent story. In many ways, confabulation in the patient unaware of the true nature of their surroundings or disrupted brain processes is the same storytelling we all use to make sense of the inconsistencies that punctuate our lives when we deviate from the normal storyline of what we believe we are our selves.