Surely it's a very long time since any psychology experiment conducted on groups of students has had a valid result.
All psychology students (and most reading people) know that any experiment is very likely to be looking for something which is not explained to the participants - a kind of trick. Participants may be enjoying working out what the object of the experiment actually is, and their reactions will not be natural.
If this is a well-known problem, how is it being solved?
Can anyone refute this, please?