Contents

48 PART I: General IssuesKey ConceptBy far the most challenging condition researchers must meet in order tomake a causal inference is eliminating other plausible alternative causes. Considera study in which the effect of two different teaching approaches (activeand passive) is assessed. Suppose the researcher assigns students to teachingconditions by having all men in one group and all women in the other. If thiswere done, any difference between the two groups could be due either to theteaching method or to the gender of the students. Thus, the researcher wouldnot be able to determine whether the difference in performance between thetwo groups was due to the independent variable she tested (active or passivelearning) or to the alternative explanation of students’ gender. Said more formally,the independent variable of teaching method would be “confounded”with the independent variable of gender. Confounding occurs when two potentiallyeffective independent variables are allowed to covary simultaneously.When research is confounded, it is impossible to determine what variable isresponsible for any obtained difference in performance.Researchers seek to explain the causes of phenomena by conductingexperiments. However, even when a carefully controlled experiment allows theresearcher to form a causal inference, additional questions remain. One importantquestion concerns the extent to which the findings of the experiment applyonly to the people who participated in the experiment. Researchers often seekto generalize their findings to describe people who did not participate in theexperiment.Many of the participants in psychology research are introductory psychologystudents in colleges and universities. Are psychologists developingprinciples that apply only to college freshmen and sophomores? Similarly,laboratory re search is often conducted under more controlled conditions thanare found in natural settings. Thus, an important task of the scientist is to determinewhether laboratory findings generalize to the “real world.” Some peopleautomatically assume that laboratory research is useless or irrelevant to realworldconcerns. However, as we explore research methods throughout thistext, we will see that these views about the relationship between laboratoryscience and the real world are not helpful or satisfying. Instead, psychologistsrecognize the importance of both: Findings from laboratory experiments helpto explain phenomena, and this knowledge is applied to real-world problemsin research and interventions.Application• In applied research, psychologists apply their knowledge and researchmethods to improve people’s lives.• Psychologists conduct basic research to gain knowledge about behavior andmental processes and to test theories.The fourth goal of research in psychology is application. Although psychologistsare interested in describing, predicting, and explaining behaviorand mental processes, this knowledge doesn’t exist in a vacuum. Instead, thisknowledge exists in a world in which people suffer from mental disorders andare victims of violence and aggression, and in which stereotypes and prejudices