Krista and Tatiana Hogan are craniopagus twins, meaning they’re connected at the head.
They share a structure that connects Krista’s thalamus to Tatiana’s. The thalamus is a double-lobed organ that plays important roles in processing sensory input and creating consciousness.
Since Krista’s and Tatiana’s thalami are connected, scientists and members of the Hogan family think the girls might view the world differently than the rest of us do.
For example, Dr. Cochrane believes the girls can see through each other’s eyes. He came to this conclusion after covering Krista’s eyes, placing electrodes on her head, and watched Krista’s brain respond after shining a light in Tatiana’s pupils.
Other times, one girl will be watching TV while the other is looking somewhere else. Suddenly, the twin not watching TV will start laughing at what’s happening onscreen.
Their “thalamic bridge” also affects their sense of taste. Krista is a ketchup fiend, but Tatiana hates the stuff. Once, Krista was eating ketchup, and Tatiana furiously tried to wipe it off her own tongue even though she wasn’t eating any ketchup herself.
Perhaps the strangest phenomenon of all is that the twins sometimes use the word “I” to describe both of themselves at once.
As of 2011, no one had run any conclusive tests on the girls and their odd condition. However, scientists who have observed their behavior and brain scans are flabbergasted and excited. While no one can say for sure at the moment, it really does seem Krista and Tatiana can share private thoughts and perceive what the other is sensing.
As someone who wants to study consciousness in the future, I can say this is one of the most extraordinary cases I have ever heard of.