RESEARCH IN ABNORMAL PSYCHOLOGY; CHAPTER 2 WHY DO WE NEED RESEARCH METHODS? PURPOSE OF RESEARCH IN CLINICAL PSYCHOLOGY To discover universal laws/principles of abnormal psychological functioning To gain a nomothetic (vs. idiographic) understanding of abnormal psychology CLINICAL RESEARCH METHODS Psychologists use the scientific method to gain information about abnormal psychological functioning They generate and then test hypotheses about how variables are related to each other…and draw conclusions about why the relationships existCLINICAL RESEARCH Types of clinical research: Case Study Correlational Method Experimental Method CASE STUDIES EVALUATING THE CASE STUDY What are some Pros? Source of new ideas May offer tentative support for or challenge a theory Richness of data What are some Cons? Observers are biased Data collection relies on subjective evidence (low internal validity) Low external validity Correlational Method Design used to determine how much events or characteristics vary with each other Use correlations to assess relationship strength and direction▪ r varies from -1 to 1 A correlation does NOT imply that one variable causes another Examples:▪ Ice cream and crime▪ Weight and use of sweet ‘n low▪ Dumbo’s feather▪ Therapeutic alliance and symptom improvement Special Forms of Correlational Research Epidemiological Studies▪ Reveal the incidence and prevalence of a disorder in a population Incidence: number of new cases in a certain period of time Prevalence: total number of cases over a period of time Longitudinal Studies EVALUATING THE CORRELATIONAL METHOD What are some pros?▪ High external validity (can generalize findings)▪ Can replicate What are some cons?▪ Low internal validity Results do not explain relationships EXPERIMENTAL METHOD Design where an independent variable is manipulated and the effects of this manipulation are observed on a dependent variable. Variables Independent variable (IV): Variable the experimenter manipulates to see if it causes change in the DV Dependent variable (DV): Variable the experimenter measures, to see if the IV had an effect on it Confounding variable (confounds): Variables other than the IV that causes a difference between groups on the DV Inferential statisticsStatistical Significance vs. Practical SignificanceStatistical significance: the likelihood that a result will not happen by chance does NOT indicate the IMPORTANCE of the result Likelihood that improvement was caused by treatment Practical/Clinical significance: Is the improvement meaningful in the individual’s life Experimental Group: receives the manipulation you’re interested in, for example the treatment you’re studying Control Group : does not receive manipulation you’re interested in, but possibly something else that is similar MORE EXPERIMENT TERMS Random Assignment: Randomly sort participants into groups Placebo Effect: Improvements resulting from expectation alone Example: Sugar pill decreasing symptoms of depression MORE EXPERIMENT TERMS Experimenter Bias : Researchers unintentionally bias the outcomes of their study Double Blind Design : Neither researchers nor subjects know who is in the experimental or control group Alternative Experimental Designs Quasi-Experimental (Mixed) Design e.g., Child Abuse as Predictor of Mood Disorder Natural Experiments e.g., Anxiety in Katrina survivors Analogue Experiments e.g., Medication research in “depressed” rats Single-subject research e.g., Treating extreme food refusal (reward /
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