Okay, attribution wise I'm kinda lost.. but "SOMEONE" said... :) > > > Not in this case....the power of the experiment is that you're able to > > > ferrett out the causal element... > > > > > > Take a population of subjects and split them in two (or three, four, etc.) > > > such that if you compare the resulting groups to each other, there is no > > > substantive difference. There aren't more women than men, there aren't > > > significant income differences, etc. > > > > > > Then you expose one group to one set of stimuli, and expose the other > > > group to some sort of placebo. > > > > > > The difference in the response to the dependent variable HAS to come from > > > exposure to the stimuli.
Not a flame, just a comment: The idea that the difference in response "HAS to come from exposure to stimuli", and that you could find groups of people who have "no substantive difference" seems a little simplistic to me. IMHO this approach is probably not generally applicable to humans. It seems that humans (from an outsider's point of view) have a penchant for acting on impulse or whim. Even though someone's actions may be entirely consistent within their own internal framework, those actions may seem irrational to an outside observer. I'm not sure that it's possible to define a 'standard' human being, let alone bring together a group of these standard human beings against which responses can be measured. Sven
