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 were 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

Question

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 were 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

Quizplus · Accepted Answer

This phenomenon is known as the experimenter effect, where the experimenter's expectations or beliefs unconsciously affect the behavior of the subjects. In this case, the experimenter's expectation that Group 1 rats were smarter may have led them to train and interact with those rats more positively and enthusiastically, which in turn motivated the rats to learn faster. Therefore, the experimenter's bias influenced the outcome of the experiment.

Two Groups of Graduate Students Were Given Rats and Were