Susan Conducts a Study to Determine Which Method Is Most

Multiple Choice

Susan conducts a study to determine which method is most effective in treating depression. Each participant receives two months of behavioral therapy, two months of cognitive therapy, and two months of humanistic therapy using a completely counterbalanced design. Susan finds that whatever type of therapy is last produces the most benefits. Susan has encountered a problem known as

A) experimenter bias.
B) order effects.
C) demand characteristics.
D) social desirability.