Overlearning helps increase:

Widely abused illegal drugs such as cocaine, heroin, and amphetamines are attractive to users because

a. they stimulate the brain's "reward circuits." b. they helped our ancestors survive and reproduce. c. they suppress REM sleep. d. they slow down mental and physical activity. e. they produce hallucinations and delusions.

One way to reduce the effects of the presence of the observer on the behavior of the observed is to

a. conceal the observer or use hidden camera recorders. b. take careful notes using a rating scale. c. make friends with the observed. d. record only selected details by using a behavioral assessment instrument.