An interesting observation I read about a week or two ago when this first popped up was that not a single boy changed the sex of their prototypical scientist - every one was male - but some of the girls who drew males first did.
Of course not. Boys envision themselves as scientists in the future (at least I did), and so they project some of their traits onto the prototype. It wouldn't make sense if I, at 12, said 'I want to be a scientist.' and then all the scientists I drew were women.
In general what happened was that after the visit the kids start identifying scientists as actual people rather than an archetype, and thus, closer to themselves.
