The only information my textbook gives me is this: We classify experimental manipulations into three broad types, depending on whether they involve variations in the physical, social, or instructional features of the experimental context. Social manipulations are usually dependent on some action of another human being within the experimental situation, often a research accomplice working for the experimenter. Environmental treatments entail the s ystematic manipulation of some aspect of the physical setting. Instructional manipulations usually are presented to the participant by the experimenter as part of the description of the purposes and procedures of the study(the “ cover story” ).Usually, different treatment varieties are combined in same study, but for illustrative purposes we discuss them as “ pure”types. (the source is Principals and Methods of Social Research by William D. Cramwell and brewer, but my book doesn't go into as much detail as theirs) So we're explained an experiment where a person is given an aptitude test and then told they are competent or not to do a job, but regardless of that they are given this job. They then need to decide who will help them do this job and the experimenters are interested in seeing if the people who believe themselves to be incompetent will choose other incompetent people to work with them, or will choose competent ones. As far as I know the test was fake, and the actual suitability for the job was not related to their answers. It also involves stimulus manipulation as the people are looking at two different candidates to work with them and the experimenters wanted to find out if perception would be effected or just the decision itself about how to work with. So which of the three types of manipulation would you say it is? Seeing as how I have to write a whole essay in Spanish explaining my answer I don't think you'll be spoon feeding me, but I'm really happy with any hint anyone can give me at all. I would say it can't be environmental, since it's not a physical change that's been being made, it's more their perception of self that's being manipulated. Which leaves the other two... Help?