At 15:43 -0800 10/25/01, Alan Kay wrote:
>It is certainly difficult to get definitive results from observing learners. There are so many artifacts to deal with.
>
>In our observations of "zillions of children", particularly with several hundred children in the last year using Etoys, a workable generalization is that the second script that they make almost always runs concurrently with the first script that they made. They are also quite good at thinking out parallel conditionals, and not so good at (they hardly ever do) nested conditionals.
>
>     Another generalization that works pretty well is that children before the age of 11 or 12 are not very good at large scale sequential planning, but are pretty good at cause-effect relationships on a small scale. We used to call these "bird's nest algorithms" when we were doing Playground in the late 80s. What I mean by this is that they were pretty darn good at looking at a situation, seeing a *one-step* that would improve it, and coming up with the conditional-action code to do that one step. Even 3rd graders were quite good at this. Then they could look at the next situation and do the same. Children of this age were not good at all in coming up with multiple sequential operations that would yield some effect. (No one knows whether this is teachable at ages 7-10. Piaget would say "probably not", but it reall
>     Playground was an OOP language in which objects were very much like a collection of spreadsheetcells, and the "cell method" was basically a condition-action pair. Everything was concurrent.
>
>       (This is where an experimental language we made -- called Tableau -- came from. It was later made into a language calledKidSim, then Cocoa, then StageCast. However, this way of doing things was pretty limited and we abandoned it early. I still don't think the StageCast route is really the way to do the before-after programming.)
...

I found Cocoa on the Apple Research web site one day and I had a lot of fun playing with it one weekend. Its limitations were obvious but I was surprised how much one could do with it. I wrote a maze crawler (using the 'hold one finger to the wall at all times' algorithm) among other things. The programming model was really different, though it didn't scale and was far too concrete.

It's too bad there isn't some way to go back and run old software like one can go back and read old journals or books. Cocoa needs to be experienced for a day to really get a feel for the strengths and weaknesses of the approach.

Dave
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_______________________________
David N. Smith
IBM T J Watson Research Center
Hawthorne, NY
dnsmith at watson.ibm.com