And through analysis and examination of all kinds of neurologic cases, you realized there are consciousnesses all over the brain! One of the fundamental facts of split-brain research that people have to remember is that you can take any normal person and normal brain and disconnect the hemispheres and all of a sudden you have two consciousnesses. What can split-brain research teach us about normal brains? Once you're onto that as a big feature of the human condition, you could then see how you can take that kind of interpretive system and build larger stories about meaning and why we're doing things and our origins, and all the rest of it.
The left hand had to pick a related image, and one was a shovel, so the left hand pointed to the shovel.Īfterward, we asked the patient, sort of confrontationally, "Why did you do that? Why did you point to the chicken and the shovel?" And the patient said, "Well, the chicken claw goes with the chicken, and you need a shovel to clean out the chicken shed." And we realized - BOOM! - we do that all day long! We have all these separate systems, these impulses, these emotions, these behaviors, all this stuff, and we're constantly thinking about it and spinning it into a story that fits. At the same time, we showed to the left eye a New England snow scene. So, the chicken claw obviously goes with the chicken. The right hand had to pick a related drawing, and one was a chicken. For example, we showed the right eye of one patient a picture a chicken claw. Well, over time, as our experiments evolved, rather than just asking patients to identify what they saw, we asked them to select objects or drawings to match the images we showed them, and then we would ask them to explain themselves. What are "functions of the human condition"? If you start with a normal, intact brain with things duplicated on each side and you need more cortical space to add on all the new, higher functions of the human condition, you're gonna say, "Maybe let's recraft some of this space and just use one hemisphere, so we have more space for another capacity." But as I say, it's just speculation it's not in the category of "we know how it works." One simple idea that we've offered is that the human is really set with more capacities than fewer, and each one of those capacities takes up some kind of neural space. And then in humans, there starts to be this vast amount of lateral specialization. Up until you get to the human brain, if you look at monkeys and chimps, both sides of the brain serve basically the same functions. Well, people have been wondering about lateralization of the nervous system for a long time, and there are many theories, but it's basically not known. So what's the benefit of having the two halves of the brain specialized like that? These experiments showed for the first time that each brain hemisphere has specialized tasks. So the right brain knew what it was seeing it just couldn't talk about it. If allowed to respond nonverbally, however, the right brain could adeptly point at or draw what was seen by the left eye. But when a picture was flashed in front of the left eye, which connects to the right side of the brain, the patient would report seeing nothing. When Gazzaniga and his colleagues flashed a picture in front of a patient's right eye, the information was processed in the left side of the brain and the split-brain patient could easily describe the scene verbally. Working in the lab of Roger Sperry, who later won a Nobel Prize for his work, Gazzaniga discovered that the two halves of the brain experience the world quite differently.
#VICTORIA 2 CONSCIOUSNESS SERIES#
In the 1960s, a young neuroscientist named Michael Gazzaniga began a series of experiments with split-brain patients that would change our understanding of the human brain forever.
But what may be even more amazing is that most people who have split-brain surgery don't notice anything different at all.īut there's more to the story than that. After surgery to treat her epilepsy severed the connection between the two halves of her brain, Karen's left hand took on a mind of its own, acting against her will to undress or even to slap her.
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