[From Bruce Gregory (960425.1415 EDT)]
(Bill Powers 960425.1030 MDT)
Responding to
(Richard Thurman 960424.1310)--
Remember that Gazzaniga presented the word "laugh" to the right
hemisphere of a subject and the subject laughed. When asked why he
laughed, the subject said something like "You guys come all the way
up here to do these tests every month. What a strange job." It
seems the left brain of the subject made up the reason because it
did not have access to the right brain's instructions.
If the right hemisphere doesn't deal in words, how come the right
hemisphere could understand and answer the question? And how did
Gazzinaga manage to ask only the right hemisphere without the left one
hearing and answering the question?
You assume that the right hemisphere could understand and answer the
question. Gazzaniga assumes that the left hemisphere controls
speaking and that therefore it heard the question, knew the "body" had
laughed, and, without being aware that it was doing so, fabricated an
answer that made sense. This phenomenon goes back before the
split-brain studies. I recall reading many years ago about a person
who was given a post-hypnotic suggestion that five minutes after he
awakened from the trance we would go from the living room into the
hall, remove an umbrella from the closet, bring it into the living
room and open it. He followed this instruction. When asked the
hypnotist why he had done this, the subject responded to the effect
that many people are superstitious about opening an umbrella inside
the house and he just wanted to show people that nothing bad happens
if you do...
Gazzaniga typically made use of the topology of the optic chiasma to
present images to one hemisphere and exclude them from the other. He
describes many experiments where the hemisphere not privy to the image
"explains" the bodies reaction to an image (such as blushing when
shown an erotic picture or an image of Rush Limbaugh tickling Rick
Marken) the explaining hemisphere has not seen.
Bruce G.