Two Groups of Graduate Students Were Given Rats and Were

Multiple Choice

Two groups of graduate students were given rats and were told to teach them how to run mazes.Group 1 was told that they had "very smart" rats that should learn quickly.Group 2 was told that they had "very stupid" rats that should learn slowly.In actuality,neither group was any different and the rats had been randomly assigned.In spite of that,when the experiment concluded,Group 1 rats had learned the maze much more quickly.How can that be explained?

A) experimenter effect
B) placebo effect
C) subject bias
D) treatment effect