In a study of the effects of humor on memory, Schmidt (1994) assigned participants to read either humorous
sentences or nonhumorous sentences and then later tested participants' memory for the sentences. The
experimental group in this experiment was:
the group of participants assigned to read humorous sentences.
Which of these partially explains the relatively high rate of Type I errors?
the tendency of journals to publish
"exciting" findings—that is, ones that report positive outcomes.
Goldstein et al. (1997) found that playing puzzle-like video games improved the reaction speed of elderly
individuals. If no subsequent studies are able to replicate this finding, then the original researchers may have:
A social psychologist is interested in whether lowering a person's self-esteem increases their level of
aggression. All of her participants complete a difficult math exam and some of them are given inaccurate,
negative results (e.g., "you missed all of the questions," or "this is the lowest score I've ever seen") that are
designed to lower their self-esteem. Other participants do not receive the negative feedback. Later, all the
participants are given the opportunity to shock another person (presumably as part of a different study).
If Dr. Pitt used random assignment in her research, then she can make the reasonable assumption that:
experimental and control groups have similar characteristics prior to receiving the experimental treatment.