Assignment:
Research Methods in Psychology
1. Read the following summary of published research and answer the questions found at the end.
Reference: Skowronski, J.J., & Thompson, C.P. (1990). Reconstructing the dates of personal events: Gender differences in accuracy. Applied Cognitive Psychology, 4, 371-381.
Article Summary: According to the authors of this study, a commonly held stereotype is that women are more concerned with (and attentive to) dates of past events than are men. This stereotype may imply that in general women are better than men at reconstructing the dates of past events. To test this implication, the results of four studies investigating memory for past events were analyzed for gender differences. In all the studies subjects were asked to keep a diary for about 3 months. They were instructed to write down each day a short description of one unique personal event. At the end of the 3-month period, subjects' memory of the events and their ability to date the events was assessed. The list of personal events was read aloud to subjects in a random order. Each subject indicated on a 7-point scale how well the event was remembered (1=not at all to 7=perfectly. For events that were remembered, the subject attempted to identify the exact date and day of the week on which the event occurred. Memory for dates was measured using the median error made in estimating the dates for each subject. The means of these error scores for males and females were compared in each of the four studies. In three studies, female mean errors were less than male mean errors. Two of these differences were statistically significant. For the fourth comparison there was a slight and nonsignificant difference in favor of the males. Overall the investigators viewed the data as suggesting that women are slightly better at reconstructing dates than are men. It is not clear whether this finding occurred because women are better able than men to organize temporal events or because of some artifact of the record keeping process (e.g., women may have written more detailed, and hence more memorable, descriptions in their diaries).
a. What are the independent and dependent variables in this study? Note: There is one independent (suspected cause) and 2 dependent (suspected effect) variables.
b. Identify the specific levels of the independent variable. Were the levels of the independent variable manipulated or selected? Explain.
c. If one were to correlate subjects' responses on the 7-point scale of how well the event was remembered and time (in days) between the date of the experiment and the date the event actually occurred, what would you expect? Properly graph and explain the relationship of the two variables in terms of magnitude and direction (I want both numbers and words). Also, describe how the two variables change together; be sure to use the units of each variable in your description. Note: The "suspected cause" variable goes on the x-axis, the "suspected effect" on the y-axis. Also, do not graph by gender; put everyone together on the same graph and do not differentiate male and female data points.
2. In the following description of research the independent variable of interest is confounded with another potentially relevant independent variable. Identify the confounding variable. Also state exactly what conclusion can be supported on the basis of the evidence presented. Finally, suggest a way in which the study could be done so that it would be internally valid.
An animal physiologist developed a drug that she thought would revolutionize the world of horse racing. She named the drug Speedo, and it was her contention that this drug would lead horses to run much faster than they do now. She selected two groups of horses and gave one of the groups injections of Speedo once a week for 4 weeks. Because Speedo was known to have adverse effects on the horses' digestive systems, those horses given the Speedo had to be placed on a special high-protein diet. Those horses not given the Speedo were maintained on their regular diet. After the 4-week period, all the horses were timed in a 2-mile race and the mean times for the horses given Speedo were significantly faster than the mean times for those not given Speedo. The physiologist concluded that her drug was effective.