Abnormal PsychologyChapter 2: Research in Abnormal PsychologyDefinitions: - Nomothetic Understanding - a general understanding of the nature, causes, and treatments of abnormal psychological functioning in the form of laws or principles.- Scientific Method - the process of systematically gathering and evaluating information through careful observations to gain an understanding of a phenomenon.- Hypothesis - a hunch or prediction that certain variables are related in certain ways.- Case Study - a detailed account of a person’s life and psychological problems.- Internal Validity - the accuracy with which a study can pinpoint one of various possible factors as the cause of phenomenon.- External Validity - the degree to which the results of a study may be generalized beyond that study.- Correlation - the degree to which events or characteristics vary along with each other.- Correlational Method - a research procedure used to determine how much events or characteristics vary along with each other. - Epidemiological Study - a study that measures the incidence and prevalence of a disorder in a given population.- Incidence - the number of new cases of a disorder occurring in a population over a specific period of time. - Prevalence - the total number of cases of a disorder occurring in a population over aspecific period of time.- Longitudinal Study - a study that observes the same participants on many occasions over a long period of time. - Experiment - a research procedure in which a variable is manipulated and the effectof the manipulation is observed. - Independent Variable - the variable in an experiment that is manipulated to determine whether it has an effect on another variable.- Dependent Variable - the variable in an experiment that is expected to change as the independent variable is manipulated.- Confound - in an experiment, a variable other than the independent variable that is also acting on the dependent variable.- Control Group - in an experiment, a group of participants who are not exposed to the independent variable.- Experimental Group - in an experiment, the participants who are exposed to the independent variable under investigation.- Random Assignment - a selection procedure that ensure that participants are randomly placed either in the control group or in the experimental group. - Blind Design - an experiment in which participants do not know whether they are inthe experimental or the control condition.- Placebo Therapy - a sham treatment that the participant in an experiment believes to be genuine. - Double-Blind Design - experimental procedure in which neither the participant northe experimenter knows whether the participant has received the experimental treatment or placebo.- Quasi-Experiment - an experiment in which investigators make use of control and experimental groups that already exist in the world at large. Also called a mixed design.- Natural Experiment - an experiment in which nature, rather than the experimenter,manipulates an independent variable.- Analogue Experiment - a research method in which the experimenter produces abnormal-like behavior in laboratory participants and then conducts experiments on the participants.- Single-Subject Experimental Design - a research method in which a single participant is observed and measured both before and after the manipulation of an independent variable. Key Concepts:What Do Clinical Researchers Do?o researchers use the scientific method to uncover nomothetic characteristics of abnormal psychologyo 3 methods used to examine relationships between variables1. case study2. correlational method3. experimental methodCase Studyo detailed account of a person’s life & psychological problemso purposes…i. source of ideas about behaviorii. support for theoriesiii. challenges existing theoriesiv. clarifies new treatment techniquesv. offers as an opportunity to study rare caseso downfalls…i. observer biasii. relies on subjective evidenceiii. low internal & external validity Correlational Methodo systematic observation of the degree to which events or characteristics vary togethero allows researchers to draw broad conclusions about abnormality in the population at largeo correlation may have a POSITIVE or NEGATIVE DIRECTIONo correlation may be HIGH or LOW in MAGNITUDEo correlational coefficient= ro p <.05  correlation is considered statistically significant o high external validityo low internal validityo two widely used forms 1. epidemiological studiesgoal DESCRIBE the incidence or prevalence of a disorder within groups or populations without trying to predict or explain why it occurs2. longitudinal studiesgoal observe the same participants over a long period of time Experimental Methodo researchers manipulate suspected causes to see whether expected effects will resulto aspects of an experimenti. independent variableii. dependent variableiii. control groupiv. experimental groupv. random assignmentvi. confoundsvii. blind designsAlternative Experimental Designso quasi-experimental design  use of groups that already exist because making control and experimental groups may be unethical example: effects of child abusei. children who have been abused (group 1)ii. matched control participants (group 2) children of the same age, sex, race, etc. as those in group 1o natural experiments  nature itself manipulates the independent variable example: participants who have just experienced a natural disaster vs. participants of neighboring cities who were not affected (matched control participants)o analogue experiments  often use animals as participants induce laboratory participants to behave in ways that seem to resemble real-life abnormal behavior example: depression feeling of loss of control over one’s lifei. laboratory participants subjected to loud noises and shocksii. emotions are monitoredo single-subject experiment  rare disorders = few participants ABAB design subject is its own comparison groupi. baseline period & application/removal of independent variable (IV) ii. participant is exposed to the variable and then it is removed for researchers to compare the subject’s behavioriii. IV applied (condition A)iv. IV removed (condition B)v. IV applied (condition A, again)vi. IV removed (condition B,