Our Brains Constantly Confabulate Stories

"We showed a split-brain patient two pictures: To his right visual field, a chicken claw, so the left hemisphere saw only the claw picture, and to the left visual field, a snow scene, so the right hemisphere saw only that. He was then asked to choose a picture from an array placed in full view in front of him, which both hemispheres could see. His left hand pointed to a shovel (which was the most appropriate answer for the snow scene) and his right hand pointed to a chicken (the most appropriate answer for the chicken claw).

We asked why he chose those items. His left-hemisphere speech center replied, “Oh, that’s simple. The chicken claw goes with the chicken,” easily explaining what it knew. It had seen the chicken claw. Then, looking down at his left hand pointing to the shovel, without missing a beat, he said, “And you need a shovel to clean out the chicken shed.” Immediately, the left brain, observing the left hand’s response without the knowledge of why it had picked that item, put it into a context that would explain it. It knew nothing about the snow scene, but it had to explain the shovel in front of his left hand. Well, chickens do make a mess, and you have to clean it up. Ah, that’s it! Makes sense.

What was interesting was that the left hemisphere did not say, “I don’t know,” which was the correct answer. It made up a post hoc answer that fit the situation. It confabulated, taking cues from what it knew and putting them together in an answer that made sense.

We called this left-hemisphere process the interpreter. It is the left hemisphere that engages in the human tendency to find order in chaos, that tries to fit everything into a story and put it into a context. It seems driven to hypothesize about the structure of the world even in the face of evidence that no pattern exists."