Reference no: EM132321281

Identify whether or not there is an internal validity threat in the following two scenarios. 

1. Mary, a psychology student hoping to enroll in law school, was interested in the malleability of people's recollections. She conducted the following experiment. She randomly divided subjects from her volunteer list into an Experimental Group and a Control Group. On Day 1, Experimental Group subjects were shown a videotape of a husband and wife squabbling, after which they answered questions about what they saw. One of these questions was phrased: "Did you hear the profanity?" In fact, the argument did not contain any swearing. On Day 2, they viewed the same videotape. This time the wording of that one question was altered to: "Did you hear any profanity?" Also on Day 2, Control Group subjects watched the videotape and were asked: "Did you hear the profanity?" Consistent with Mary's expectations, Experimental Group subjects' were less likely to recall hearing profanity in response to the second question than to the first question; and, on Day 2, reports of hearing profanity by Experimental Group subjects were fewer than by Control Group subjects. Mary concluded that what her subjects remembered was influenced by how she worded the leading question.
2. Behavioral researchers attempted to use their skills to combat the problem of impaired driving. For one month, on Saturday nights they measured the blood alcohol content (BAC) of departing patrons at each of two taverns (Baseline). The patrons were compensated for agreeing to do this with lottery tickets. Then, they implemented a treatment package, which included (1) placing cards on tables in the taverns instructing patrons how to pace their drinking to stay under the legal limit, (2) providing individual feedback on BAC to departing patrons, and (3) posting a large poster in each tavern indicating the percentage of patrons who drove home intoxicated the previous week. Data continued to be recorded for one more month on Wednesday nights (Treatment). We can conclude that the treatment package reduced the mean BAC of departing patrons at each of the two taverns.