7. Capgras Delusion
Imagine a scenario where someone you know suffers a traumatic head injury in an accident but luckily survives. Then the person wakes up and no longer believes that you are you. Instead, he thinks you’re an impostor.
This is known as the Capgras delusion and is believed to occur after someone sustains damage to the superior temporal sulcus, an area in the brain believed to be important in attributing emotional feelings to a person.
Even though the sufferer can still recognize faces, he can’t attribute feelings to the recognized individual and so believes that person to be an imposter. This also applies to the sufferer’s pets. He will believe that one of the impostors living with him has also replaced his dog.
Even stranger, those with the delusion often know how absurd these feelings are. But as the visual sense is so dominant in humans, they find it hard to disregard the feeling that everyone they know has been replaced.
6. Urbach-Wiethe Disease
Ever think it would be nice to be fearless? Patient SM, who suffers from Urbach-Wiethe disease, experiences just that. The disease causes both of her amygdalae (believed by many to be the fear centers of the brain) to selectively deteriorate.
To test whether SM’s fearlessness applied to a variety of situations, psychologists took the woman to the haunted house at Waverly Hills Sanatorium in Louisville, Kentucky. When she was going through the house, SM was not scared whatsoever. Instead, she smiled and laughed at the haunted house.
As some people don’t find haunted houses scary, the psychologists took SM to a pet store after she said that she hated snakes. Once there, she rubbed their scales and held them. Psychologists reported that she acted curious and interested rather than frightened of the snakes.