This is true - but remember it's all relative. If most universities are drawing from approximately the same sample (e.g. university undergrads) then you essentially have a within subjects design. Still, that's why the science that survives is repeatable.
As to the question of the MIT students, I recently saw a talk by this group and I have little doubt that the effects are an automatic function of visual memory. Participants just knew which objects they had seen. The results should replicate very nicely even at lower ranked schools. Indeed, I bet middle school kids would show the same effects.
I don't think they recruited exclusively students though. I believe mixed in to the sample were folks off Craigslist. If you're really interested you could always send an email to one of the co-authors. You're more likely to hear back from one of the grad students.
As to the question of the MIT students, I recently saw a talk by this group and I have little doubt that the effects are an automatic function of visual memory. Participants just knew which objects they had seen. The results should replicate very nicely even at lower ranked schools. Indeed, I bet middle school kids would show the same effects.
I don't think they recruited exclusively students though. I believe mixed in to the sample were folks off Craigslist. If you're really interested you could always send an email to one of the co-authors. You're more likely to hear back from one of the grad students.