Research indicates that by age 10, the most important aspect of friendship is usually

When neither the person taking the drug nor the person evaluating the effects of the drug knows which people are getting the experimental drug and which people are getting the placebo, this procedure is referred to as a(n)

A. design flaw. B. effect size. C. preclinical study. D. double-blind procedure.

Reacting to a stimulus that is similar to the one you have learned to react to is called ___________

a. stimulus generalization b. response generalization c. higher-order conditioning d. modeling