What is it like to feel someone else’s feelings and feel the presence of another in your head? No, this is not about hallucinations and not about fantasies, but about one brain for two. The story of Siamese twins Krista and Tatiana Hogan.
At first it seems that Krista and Tatiana just leaned their heads against each other. But it is worth taking a closer look at the photographs, and it becomes clear: the head of one girl smoothly passes into the head of another. The Hogan sisters, who are now ten years old, are Siamese twins with a very rare form of fusion: the bow passes in the region of the skull. The girls are quite healthy and intellectually developed for their age. But there is a circumstance that draws the attention of neuroscientists to them. “Here, you see this light line in the middle,” neurosurgeon Douglas Cochrane shows an x-ray. “This is the thalamic bridge. It connects the two brains in an area called the thalamus.» In the brain of an ordinary person, this area acts as a switch for signals from different senses. Some scientists and philosophers believe that the thalamo-cortical system (that is, the neural pathways between the thalamus and the cortex) may be the key to how sensory data creates consciousness. The case of Krista and Tatiana Hogan adds to the theory: the bridge that connects their thalamus seems to allow them to exchange information on a sensory level.
One day, while watching a comedy, the parents noticed that both girls were laughing, although one of them could not see what was happening on the screen. Over time, more and more signs began to appear that the condition of one of the sisters could be transferred to the other. For example, when Krista was given ketchup, Tatyana, who did not like him, made a grimace. When they were two years old, Douglas Cochrane conducted an experiment: a light flashed before Tatyana’s eyes, while electrodes on Krista’s head recorded brain activity in the occipital lobe, which processes visual images. But can girls read each other’s thoughts, influence each other’s minds? Some signs indicate that a form of telepathic communication is possible between them. Krista and Tatiana hardly speak to each other. But if one wants to eat, the other can immediately say: «We are hungry.» Sometimes Krista and Tatyana literally pluck desires and thoughts from each other’s tongues.
- She was told: «Your son cannot study.» Mother believed that she could
With all this, it is obvious that the sisters remain individuals. Parents confidently report that each of them has their own tastes and preferences. Does this mean that each of them, despite the constant exchange of sensations, can still determine the boundary between themselves and their sister? According to neuroscientist Antonio Damasio, a complete mind meld is impossible. The sisters only share the echoes of sensations without having a common mental space.1. Their minds remain neighbors who regularly exchange news, but do not dare to cross someone else’s threshold.
But what if Krista and Tatiana have a special form of consciousness in which «we» and «I» do not contradict each other? Growing up, each of us goes from merging with the mother’s body to realizing and even aggressively defending our «I». But at the same time, we are still able to tune in to another person — for example, if we love him. The desire to be one with the object of love and the fear of absorption are constantly fighting within us. Maybe the constant internal unity of Krista and Tatyana taught them to live with each other, not being afraid to lose themselves?
Since such a fusion of consciousnesses arose naturally, there is a possibility that someday it will be possible to create it artificially. Will we then be able to watch other people’s dreams, directly exchange memories (think of the memory pool from the Harry Potter saga), and instantly explain to others the meaning of our brilliant ideas? For now, one can only fantasize about it.
1 A. Damasio «Self Comes to Mind» (Vintage, 2012).