Reinforcement can reduce extrinsic motivation.

Which of the following is a factor that increases susceptibility to infection with sexually transmitted diseases?

A) Discussing one's sexual boundaries with one's partner B) Multiple sex partners C) Discussion of sexually transmitted diseases in high school D) Abstinence from use of drugs or alcohol

A study in which members of a group of people are tested at several different points across an extended period of time is using a __________________ design.

a) case study b)naturalistic observation c)cross-sectional d)longitudinal