Experiments With Human Subjects

Ira Brodsky (ibrodsky@ix13.ix.netcom.com)
Thu, 19 Sep 1996 11:34:09 -0600

Robin Hanson wrote:

>>The difference is that in computer science, you can design objective
>>and repeatable experiments. Most social science I have encountered
>>focuses, by necessity, on observation. While experimentation is
>>sometimes employed, it's extremely difficult to limit the number of
>I and other folks around here have run lots of experiments with human


Yes, and such experimentation is often limited by ethical concerns. In a
wave-particle duality experiment, there are no moral issues hanging over
whether you block slit "A" or slit "B". In social experiments, one is
necessarily restrained from trying all of the options.

>...I'm not sure what you mean by "objective and repeatable" or
>"limit the number of variables", so I can't yet compare them to your
>criteria. It is easy to limit the number of things you vary within
>your experiment. Bad experiments often vary too few things. And
>experiments are commonly repeated to see if the same phenomena is observed.

I'm not a research scientist, and I'm sure there are others on this list
who can articulate this better than I. By "objective," I mean that most
reasonable people would agree the experiment is fair from the outset. By
"repeatable," I mean any disinterested party could recreate the experiment
and come up with the same results.

I'm not trying to suggest social scientists *always* have political
agendas. I'm saying it is extremely difficult, and often impossible, to
design and implement social experiments that are as airtight as the best
experiments in the physical sciences.

>I'll also note that many "sciences" such as astronomy and geology rely
>almost entirely on observation. Others, such as evolutionary biology,
>find it very difficult to eliminate variance within the samples they
>experiment on.

Nope, there is plenty of experimentation in astronomy and geology. Didn't
astronomers prove that gravity can bend light waves through an experiment?
And there are many experiments one can do in geology, like mechanical
simulations, drilling through the earth's crust, etc.

But your point does make me realize that "observation" isn't the real issue
here. "Variables" is.

In the physical sciences, you can usually test one variable at a time. I
don't dispute your claim that often you need to vary more than one thing at
a time. The point is you shouldn't start doing that until after you have a
firm understanding (verified through experimentation) of what happens when
you vary each thing alone.

The problem with the social sciences is that there are external forces
varying many things *all* of the time. It's virtually impossible to
isolate any single factor. For example, how do you design a rigorous
experiment to determine whether giving welfare to unwed, teenage mothers
will reduce, increase, or have no impact on criminal activity among their
children when they grow up?

Perhaps my example is an extreme case. Please tell me a little about your
research. I read your "Idea Futures" article and thought it was excellent;
I'm even thinking about how your ideas might be applied to the cellular
telephone technology wars I am participating in.

Ira Brodsky
Datacomm Research Company
Wilmette, Illinois