In the field of psychology, scientists begin their search to discover what X does by finding instances where X is either broken or absent, then considering what functions or behaviors are affected as a result.
This kind of research is called a case study, which is really just another term for a story.
When asking the question, “What is emotion?”, it follows that the best place for us to begin is with a story about a man for whom the emotional inner-workings aren’t functioning as they should be. And that is what leads us to the story of David Silvera.
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Prior to 1999, David Silvera was a fairly ordinary person. It wasn’t until a severe car accident left him in a coma for five weeks that something incredibly peculiar happened.
When David woke up from his coma, his doctors and family were pleased to find that he hadn’t sustained any major long-term damage. His memories were intact. His thinking and cognitive abilities were normal. He was normal.
Or so it seemed.
There was only one strange thing about David following his coma: he was fully convinced that his mother and father were impostors.
There were various explanations given for David’s bizarre delusion. Some thought, at least at first, that it might just be some residual confusion from the stroke. Some determined that he was psychotic. Others proposed elaborate theories about repressed memories, cognitive dissonance, and the like.
But none of these were very satisfying answers, for (as stated earlier) he was in every other sense a perfectly normal person with intact cognitive abilities.
The answer to what ailed David, it turns out, had to do with emotion.
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Soon after his (partial) recovery, David was referred to the renowned neurologist V.S. Ramachandran.
Ramachandran spent a great amount of time with David, studying the specific nature of his delusion. They soon learned that the delusion was strictly limited to when David saw his parents. If David was in the living room, these ‘impostors’ could simply walk into the kitchen (or anywhere else where they’d be out of sight), call him on the phone, and David would instantly recognize them as his parents.
This bizarre phenomenon, studied by Ramachandran and others, is called Capgras Syndrome (or Capgras Delusion). Though there are still several competing theories to explain it (due to the incredibly small sample size of case studies), Ramachandran’s is perhaps the most widely accepted.
According to Ramachandran, David’s delusion is the result of a broken (or, at least, altered) connection between the visual and emotional pathways in the brain.
The result is that David’s brain recognizes the physical image of his mother and father, but rejects that they could actually be his parents because there’s no longer emotion accompanying that image as it is perceived by his mind. The only way of dealing with this incongruity, then, is to consider them to be impostors.
Follow-Up Post: Capgras Syndrome and Emotion
*Photo Credit: Christopher Schoenbohm (Creative Commons)