February 6, 2004
My Right Hemisphere Made Me Type This
So I’m reading The Blank Slate: The Modern Denial of Human Nature by Steven Pinker, whose books I have always really enjoyed.
I’m only forty pages in, and already it’s blowing my mind.
Okay, so you know how we think of ourselves as “I”? That is, even if you subscribe to the notion that the mind is just a bunch of biochemical processes in the physical brain (as I do) you still tend to think of it as the mind. There’s a particular you, a central nexus that gets sensory input, makes decisions, and all that.
Except there’s totally not. Check this out:
One of the most dramatic demonstrations of the illusion of the unified self comes from the neuroscientists Michael Gazzaniga and Roger Sperry, who showed that when surgeons cut the corpus callosum joining the cerebral hemispheres, they literally cut the self in two, and each hemisphere can exercise free will without the other one’s advice or consent. Even more disconcertingly, the left hemisphere constantly weaves a coherent but false account of the behavior chosen without its knowledge by the right. For example, if an experimenter flashes the command “WALK” to the right hemisphere (by keeping it in the part of the visual field that only the right hemisphere can see), the person will comply with the request and begin to walk out of the room. But when the person (specifically, the person’s left hemisphere) is asked why he just got up, he will say, in all sincerity, “To get a Coke”—rather than “I don’t really know” or “The urge just came over me” or “You’ve been testing me for years since I had the surgery, and sometimes you get me to do thing but I don’t know exactly what you asked me to do.” Similarly, if the patient’s left hemisphere is shown a chicken and his right hemisphere is shown a snowfall, and both hemispheres have to select a picture that goes with what they see (each using a different hand), the left hemisphere picks a claw (correctly) and the right picks a shovel (also correctly). But when the left hemisphere is asked why the whole person made those choices, it blithely says, “Oh, that’s simple. The chicken claw goes with the chicken, and you need a shovel to clean out the chicken shed.”
The spooky part is that we have no reason to think that the baloney-generator in the patient’s left hemisphere is behaving any differently from ours as we make sense of the inclinations emerging from the rest of our brains.
Whoahhh! I love this stuff. For a while during college (okay, like two weeks) I was totally going to go into cognitive science. How did I end up in lame old economics instead?