A Researcher Hypothesized That the Drug Amphetamine (A Stimulant)improves Learning

Multiple Choice

A researcher hypothesized that the drug amphetamine (a stimulant) improves learning. She explains her hypothesis to her participants and gives experimental group participants an amphetamine pill before they begin studying. Control group members get nothing. Later, she assesses how much each participant learned. Because of the hypothesis explanation and because the experimental group was given a pill that the other group did not receive, the experimental group will most likely expect to learn more. Thus, any observed differences between groups may reflect differences in expectation, not the actual effect of the drug, a problem known as the

A) anthropomorphic error.
B) research participant bias.
C) courtesy bias.
D) double-blind experimental effect.