Hockenbury Discovering Psychology 5th txtbk

18 CHAPTER 1 Introduction and Research MethodsFormulating a Hypothesis: Do Dogs LookLike Their Owners? Hypotheses are oftengenerated from everyday observations.For example, many people believe thatpets resemble their owners (Alpers &Gerdes, 2006). How could this hypothesisbe scientifically tested? PsychologistsMichael Roy and Nicholas Christenfeld(2004, 2005) found that study participantswere able to accurately match photos ofdogs with photos of their owners—butonly if the dogs were purebred. Other researchhas come to the same conclusion(Payne & Jaffe, 2005). The explanation?People tend to choose dogs that resemblethemselves.operational definitionA precise description of how the variables ina study will be manipulated or measured.statisticsA branch of mathematics used byresearchers to organize, summarize, andinterpret data.statistically significantA mathematical indication that researchresults are not very likely to have occurredby chance.meta-analysisA statistical technique that involves combiningand analyzing the results of manyresearch studies on a specific topic in orderto identify overall trends.replicateTo repeat or duplicate a scientific study inorder to increase confidence in the validityof the original findings.be investigated. An operational definition defines the variable in very specificterms as to how it will be measured, manipulated, or changed.Operational definitions are important because many of the concepts that psychologistsinvestigate—such as memory, happiness, or stress—can be measured in morethan one way. In providing operational definitions of the variables in the study, theresearcher spells out in very concrete and precise terms how the variables will be manipulatedor measured. In this way, other researchers can understand exactly howthe variables were measured or manipulated in a particular study.For example, prior to marrying, some couples attend a premarital education classor workshop designed to help their marriage succeed by exploring such topics as relationshipskills, expectations, resolving conflicts, and so on. You could turn that observationinto a testable hypothesis: Premarital education enhances marital quality.To test that specific prediction, you would need to formulate an operational definitionof each variable. How could you operationally define premarital education?Marital quality? What could you observe and measure that would reflect these factors?In looking at that hypothesis, Scott Stanley and his colleagues (2006) operationallydefined premarital education as the couple’s response to a question asking if they attendeda class, workshop, or counseling session designed to help them prepare formarriage. Answering “no” was scored 0, and “yes” was scored 1. Marital quality wasoperationally defined as the person’s 1-to-5 rating in response to several questionsabout their satisfaction with the marriage. Responding with 1 indicated that the personwas not at all satisfied, and 5 indicated that the person was completely satisfied.Step 2. Design the Study and Collect the DataThis step involves deciding which research method to use for collecting data. Thereare two basic categories of methodology or research methods—descriptive and experimental.Each research method answers different kinds of questions and providesdifferent kinds of evidence.Descriptive methods are research strategies for observing and describing behavior, includingidentifying the factors that seem to be associated with a particular phenomenon.Descriptive methods answer the who, what, where, and when kinds of questions aboutbehavior. Who engages in a particular behavior? What factors or events seem to be associatedwith the behavior? Where does the behavior occur? When does the behavioroccur? How often? In the next section, we’ll discuss commonly used descriptive methods,including naturalistic observation, surveys, case studies, and correlational studies.In contrast, the experimental method is used to show that one variable causeschange in a second variable. In an experiment, the researcher deliberately varies onefactor, then measures the changes produced in a second factor. Ideally, all experimentalconditions are kept as constant as possible except for the factor that theresearcher systematically varies. Then, if changes occur in the second factor, thosechanges can be attributed to the variations in the first factor.Step 3. Analyze the Data and Draw ConclusionsOnce observations have been made and measurements have been collected, the rawdata need to be analyzed and summarized. Researchers use the methods of a branchof mathematics known as statistics to analyze, summarize, and draw conclusionsabout the data they have collected.Researchers rely on statistics to determine whether their results support theirhypotheses. They also use statistics to determine whether their findings are statisticallysignificant. If a finding is statistically significant, it means that the results arenot very likely to have occurred by chance. As a rule, statistically significant resultsconfirm the hypothesis. Appendix A provides a more detailed discussion of the useof statistics in psychology research.Keep in mind that statistical significance and practical significance are not necessarilythe same thing. If a study involves a large number of participants, even smalldifferences among groups of subjects may result in a statistically significant finding.