RESEARCH STUDY 3.4
Dr. Kang, a cognitive psychologist, conducts an experiment examining the effect of emotion on memory. He provides lists of 15 words to two groups of participants at his university. He puts the names of all the participants in a hat. The first 20 names he assigns to Group A and the last 20 he assigns to Group B. Group A is given a list of words that are very emotional in content (e.g., passion, murder). Group B is given a list of words that are neutral in content (e.g., houseplant, desk). He then measures how many words each group is able to remember after being distracted for 5 minutes by watching a video about the history of the university. He finds that Group A remembers 15% more words than Group B.
-Refer to Research Study 3.4 above to answer the following question. If Dr.Kang decided against using random assignment,which of the following would be threatened?
A) The covariance of the study
B) The temporal precedence of the study
C) The internal validity of the study
D) The external validity of the study
E) The construct validity of the study

Question

Quizplus · Accepted Answer

Without random assignment, there is a potential threat to internal validity. Participants in Group A may differ from those in Group B in some systematic way other than the manipulation of emotion, which could explain the difference in memory performance. Random assignment helps ensure that groups are equivalent at the start of the study, reducing the likelihood of alternative explanations for differences in the outcome.

RESEARCH STUDY 3.4 Dr. Kang, a Cognitive Psychologist, Conducts an Experiment Examining the Experiment