Lots of concurrency

Mark Guzdial guzdial at cc.gatech.edu
Thu Oct 25 17:38:18 UTC 2001

We're getting into some of my favorite literature, so I wanted to jump in here.

>And I think it is just an illusion
>that this parallelism is only at a low level (e.g. neurons). Read Minsky's
>Society Theory of Mind ( http://www.media.mit.edu/people/minsky/ ) for

But also consider Herb Simon's arguments in opposition -- and Simon 
has a lot more empirical evidence in his favor.  I don't have an 
opinion on which is right yet, but I don't think that this is a 
settled point.

>Here's an excerpt from "MultiLogo: A Study of Children and
>Concurrent Programming" (
>http://el.www.media.mit.edu/groups/el/Papers/mres/MultiLogo/MultiLogo.html )

I really love Mitchel's MultiLogo work, but part of what I love about 
it is his honesty in how *confusing* students found all the 
concurrency.  For example, he tells a great story about a student who 
kills the launching process, and can't understand why the launched 
process doesn't stop, too.

>I think her problem is that her model of programming is sequential as a
>result of her year of Logo programming. And the world isn't sequential.
>Think of sports teams. Think of traffic. Think of the internal concurrency
>in walking. In games. Think about bank account transfers. The Incredible
>Machine. Cooking. An orchestra. And so on.

I don't find the "year of Logo programming" argument convincing. 
There are too many studies (most prominently the Pea and Kurland 
work, but even Idit Harel's and Yasmin Kafai's versions of ISDP) that 
shows that not much gets learned in a year of programming.  That deep 
mindsets about the universe get changed in a single year is a 
stretch.  (For example, Idit's and Yasmin's studies have taken more 
than a full year.)

The other examples (sports teams, traffic, etc.) seem more an 
argument that students hold a centralized, sequential model of the 
universe -- consider Mitchel's work with StarLogo and how hesitant 
the students were to release the centralized models.

It should be noted that Mitchel's StarLogo work is a dissertation 
about MENTAL MODELS OF CONTROL, *NOT* programming.  I asked Mitchel 
once about the interface that students used to StarLogo, and he told 
me that he was it.  None of his subjects actually wrote any of those 
programs!  Rather, they told Mitchel about their ideas, and he coded 
them -- explaining what he was doing -- and then worked with the kids 
to understand the results.  It's important to note that the kids 
didn't write the code.  They might have been able to, but that hasn't 
been tested  As far as I know, there have been no empirical studies 
of kids programming in StarLogo -- we don't know if it would work for 
the average kid.  So, we can't use StarLogo as an example of a 
concurrent programming language that works for kids.


Mark Guzdial : Georgia Tech : College of Computing : Atlanta, GA 30332-0280
Associate Professor - Learning Sciences & Technologies.
Collaborative Software Lab - http://coweb.cc.gatech.edu/csl/
(404) 894-5618 : Fax (404) 894-0673 : guzdial at cc.gatech.edu

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