Tuesday January 28 2014 Abnormal Psychology Chapter 2 Research in Abnormal Psychology What do clinical researchers do Researchers use the scientific method to uncover nomothetic principles of abnormal psychological functioning They attempt to identify and examine relationships between variables and depend primarily on three methods of investigation the case study the correlational method and the experimental method The Case Study A case study is a detailed account of a person s life and psychological problems It can serve as a source of ideas about behavior provide support for theories challenge theories clarify new treatment techniques or offer an opportunity to study an unusual problem Yet case studies may be reported by biased observers and rely on subjective evidence In addition they tend to have low internal validity and low external validity The Correlational Method Correlational studies systematically observe the degree to which events or characteristics vary together This method a llo w s re s e a r c h e r s t o dr a w br oad conclusions ab ou t abnormality in the population at large A correlation may have a positive or negative direction and may be high or low in magnitude It can be calculated numerically and is expressed by the correlation coefficient r Researchers perform a statistical analysis to determine w het h er t h e c o r r e l at i on f o und in a study is truly characteristic of the larger population or due to chance Correlational studies generally have high external validity but lack internal validity Two widely used forms of the correlation method are epidemiological studies and longitudinal 1 Tuesday January 28 2014 The Experimental Method In experiments researchers manipulate suspected causes to see whether expected effects will result The variable that is manipulated is called the independent variable and the variable that is expected to change as a result is called the dependent variable Confounds are variables other than the independent variable that are also acting on the dependent variable To minimize their possible influence experimenters use control groups random assignment and blind designs The findings of experiments like those correlational studies must be analyzed statistically Alternative Experimental Designs Clinical experimenters must often settle for experimental designs that are less than ideal including the quasiexperiment the natural experiment the analogue experiment and the single subject experiment The Use of Multiple Research Methods Because research participants have rights that must be respected because the origins of behavior are complex because behavior varies and because the very act of observing an individual s behavior influences that behavior it can be difficult to assess the findings of clinical research Also researchers must take into account their own biases as well as a study s unintended impact on participants usual behavior To help address such obstacles clinical investigators must use multiple research approaches 2