[From Bill Powers (971123.1129 MST)]
Thanks to Dag Forssell, I have now seen the video programs produced by
Bruce Gregory's group at the Smithsonian. Anyone who is involved with
teaching _or_ science, or both, must see these tapes.
The main theme is that children do not come into science with blank minds;
they have their own theories about how things work, and most important,
normal teaching makes essentially no change in these theories. Several of
the segments open with interviews on graduation day at Harvard University,
where randomly-selected graduates, in their robes and mortar boards, are
asked some simple science questions, like what makes summer and winter
happen, and why the moon shows phases. Most of them gave the wrong answers,
including one young man who remarked that he had majored in physics and
took some courses in relativity. Intelligence and education have almost no
effect on correcting erroneous private theories that people have held since
early school days, and have never re-examined.
One of the questions that the graduates were asked is what a piece of a
tree (a short log handed to them) was made of. They said "Soil, water, and
energy from the sun." Asked to estimate the fractions, most of them said
that water made up the bulk of the material. Not one of them mentioned the
component that makes up most of the weight: carbon, from the carbon dioxide
in the air. This was followed by an inverview with a 12-year old student
who had just completed a semester on photosynthesis. That student gave the
same wrong answers. Asked why air wasn't part of the answer, the student
replied confidently, "Oh, air doesn't weigh anything."
This student was then re-interviewed two years later, after he had learned
the right answers. He was embarrassed as he watched the earlier interview;
he felt he had let his teacher down. Of course the teacher, who was
watching the first interview on TV, said the same thing: he had let his
student down.
The main message that comes through all the segments is that one has to
deal with the pre-existing ideas before new ones can take their place. And
this has to be done through hands-on experiences with which the students
can refute their own misconceptions, rather than having the teacher do it.
A subtle underlying theme was illustrated by having teachers watch while
their brightest students explained things they had supposedly just been
taught (and on which they had passed tests). These teachers were shocked.
The first thing that had to happen was that the teachers had to refute
their own theories about what a teacher was supposed to do. At least four
of the teachers spontaneously commented that they had never realized that
the children already had their own ideas, and were not blank slates.
All through watching this series my mind kept returning to PCT and CSGnet.
So much was being explained about why some people on the net (and probably
a lot more than I know about) have such trouble with accepting the simplest
features of PCT. As one professor from the Smithsonian group explained it,
not only do children come to education with ideas of their own about how
the world works, but these ideas are precious to them; they are a very
important part of each child's life. They are strongly defended and are not
given up without a struggle. As was shown over and over, when a child
finally realises that the previous understanding was wrong, an emotional
crisis has to pass before the new idea can be accepted. It's not just a
matter of being told the right answer and saying "Oh." The first barrier
that has to be crossed is the experience of realizing that one had believed
in a wrong -- and now obviously or even ludicrously wrong -- concept. This
is hard even for children; how much harder must it be for an adult,
especially one who has grown up in a culture that puts the maximum value on
always being right?
The main thing this series taught me was the futility of simply describing
PCT and expecting people to get it. They may be able to repeat back what
you said, and even write programs that use the relationships correctly, but
when you then ask them to compare this new idea with what they already
believed, they still give you what they thought before you ever opened your
mouth. They can watch the little orrery with the moon going around the
earth and the earth going around the sun, and draw the orbits correctly,
but when you ask them what causes the phases of the moon, they say "I still
think it's clouds or the shadow of the earth."
So perception is still probability, behavior is still controlled by
reinforcements, and control must still always involve prediction and
calculation of the right output to correct the error. It makes no
difference that we can build a model and simulate behavior without any
probability, reinforcement or prediction in it. It makes no difference that
you can _do_ control behaviors without any sign of these things going on.
Somehow the old answer will still turn out to be right.
If rubber bands and computer demos don't lead to giving up these ideas,
nothing will. There is nothing that I or anyone else -- except the
believers themselves -- can do about it. If they look through the eyepiece
and see the spots on the perfect sun, they will continue to say "dust on
the lens." If you explain Newton's Laws of Motion, they will still say that
a golf ball has more "carry" in moist air. If you show them that in a truly
dark room, they cannot see (as Gregory's bunch did), they will still say "I
guess we didn't wait long enough for my eyes to get used to the dark."
All we can do is think up more demos that people can do by themselves, to
convince themselves that the PCT explanation is the right one, and the
others are wrong. No amount of criticism or yelling or persuasion or logic
will do the trick.
So let's see if I can follow my own advice.
Best,
Bill P.
