Contents

CHAPTER 2: The Scientific Method 5512 What is the difference between basic and applied research?13 What is an intervening variable? Propose a psychological construct that couldserve as an intervening variable between “insult” (present/absent) and “aggressiveresponses.” Explain how these variables might be related by proposing a hypothesisthat includes your intervening variable.14 Describe the roles of logical consistency and empirical testing in evaluating a scientifictheory.15 Explain why rigorous tests of a theory that seek to falsify a theory’s propositions canbe more informative than tests that seek to confirm a theory’s propositions.CHALLENGE QUESTIONS1 In each of the following descriptions of researchstudies, you are to identify the independentvariable(s). You should also be able to identify atleast one dependent variable in each study.A A psychologist was interested in the effect offood deprivation on motor activity. She assignedeach of 60 rats to one of four conditions differingin the length of time for which the animals weredeprived of food: 0 hours, 8 hours, 16 hours,24 hours. She then measured the amount of timethe animals spent in the activity wheel in theircages.B A physical education instructor was interestedin specifying the changes in motor coordinationthat occur as children gain experience withlarge playground equipment (e.g., slides,swings, climbing walls). For a span of 8 weeks,preschool children were assigned to 4, 6,or 8 hours per week for time allowed onthe equipment. She then tested their motorcoordination by asking them to skip, jump, andstand on one foot.C A developmental psychologist was interestedin the amount of verbal behavior very youngchildren displayed depending on who elsewas present. The children in the study were3 years old. These children were observed in alaboratory set ting for a 30-minute period. Halfof the children were assigned to a condition inwhich an adult was present with the child duringthe session. The other half of the children wereassigned to a condition in which another youngchild was present during the session with thechild being observed. The psychologist measuredthe number, duration, and complexity ofthe verbal utterances of each observed child.2 A physiological psychologist developed a drug thatshe thought would revolutionize the world of horseracing. She named the drug Speedo, and it washer contention that this drug would lead horses torun much faster than they do now. (For the sakeof this hypothetical problem, we are ignoring thefact that it is illegal to give drugs to racehorses.)She selected two groups of horses and gave oneof the groups injections of Speedo once a weekfor 4 weeks. Because Speedo was known to havesome negative effects on the horses’ digestivesystems, those horses given the Speedo had to beplaced on a special high-protein diet. Those horsesnot given the Speedo were maintained on theirregular diet. After the 4-week period, all the horseswere timed in a 2-mile race and the mean (average)times for the horses given Speedo were significantlyfaster than the mean times for those not givenSpeedo. The psychologist concluded that her drugwas effective.A Identify the independent variable of interest (andits levels) and a potentially relevant independentvariable with which the primary independentvariable is confounded. Explain clearly how theconfounding occurred.B State exactly what conclusion about the effectof the drug Speedo can be supported by theevidence presented.C Finally, suggest ways in which the studycould be done so that you could make a clearconclusion about the effectiveness of the drugSpeedo.3 The New York Times reported the results ofa 2-year, $1.5 million study by researchers atCarnegie Mellon University funded by the NationalScience Foundation and major technologycompanies. There were 169 participants inthe study drawn from the Pittsburgh area. Theresearchers examined the relationship betweenInternet use and psychological well-being. Adirector of the study stated that the study didnot involve testing extreme amounts of Internetuse. The participants were normal adults andtheir families. On average, for those who used the(continued)