Abnormal Psychology Chapter #4

dependent variable
in an experimental study, the phenomenon that is measured and expected to be influenced
external validity
extent to which research findings generalize, or apply, to people and settings not involved in the study
hypothesis
educated guess or statement to be tested by research
internal validity
extent to which the results of a study can be attributed to the independent variable after confounding alternative explanations have been ruled out
independent variable
phenomenon manipulated by the experiment in a study and expected to influence the dependent variable
research design
plan of experimentation used to test a hypothesis
testability
ability of a hypothesis, for example, to be subjected to scientific scrutiny and to be accepted or rejected, a necessary condition for the hypothesis to be useful
analog model
approach to research that employs subjects who are similar to clinical clients, allowing replication of a clinical problem under controlled conditions
confound
any factor occurring in a study that makes the results uninterpretable because its effects cannot be separated from those of the variables being studied
confounding variable
variable in a research study that was not part of the intended design and that may contribute to changes in the dependent variable
control group
group of individuals in a study who are similar to the experimental subjects in every way but are not exposed to the treatment received by the experimental group. their presence allows for a comparison of the differential effects of the treatment
generalizability
extent to which research results apply to a range of individuals not included in the study
randomization
method for placing individuals into research groups that assures each an equal chance of being assigned to any group, thus eliminating any systematic differences across groups
case study method
research procedure in which a single person or small group is studied in detail. the method does not allow conclusions about cause-and-effect relationships, and findings can be generalized only with great caution (contrast with single-case experimental designs)
clinical significance
degree to which research findings have useful and meaningful applications to real problems
effect size
statistical measure that shows the amount of difference among the members of a group in a clinical study
patient uniformity in myth
tendency to consider all members of a category as more similar than they are, ignoring their individual differences
statistical significance
probability that obtaining the observed research findings merely by chance is small
correlation
degree to which two variables are associated. in positive correlation, the two variables increase or decrease together. in a negative correlation, one variable decreases as the other increases
correlation coefficient
computed statistic reflecting the strength and direction of any association between the two variables
positive correlation
association between two variables in which one increases as the other increases
directionality
possibility that when two variables, A and B, are correlated variable A causes variable B or variable B causes variable A
epidemiology
psychopathology research method examining the prevalence, distribution, and consequences of disorders in population
negative correlation
association between two variables in which one increases as the other decreases
experiment
research method that can establish causation by manipulating the variables in question and controlling for alternative explanation of any observed effects
placebo control group
in an outcome experiment, a control group that does not receive the experimental manipulation but is given a similar procedure with an identical expectation of change, allowing the researcher to assess any placebo effect
placebo effect
behavior change resulting from the person’s expectation of change rather than from the experimental manipulation itself
comparative treatment research
outcome research that contrasts two or more treatment methods to determine which is most effective
double-blind control
procedure in outcome studies that prevents bias by ensuring that neither the subjects nor the providers of the experimental treatment know who is receiving treatment and who is receiving placebo
repeated measurement
when responses are measured on more than two occasions (not just before and after intervention) to assess trends
single-case experimental design
research tactic in which an independent variable is manipulated for a single individual, allowing for cause-and-effect conclusions but with limited generalizability (contrast with case study method)
baseline
measured rate of behavior before introduction of an intervention that allows comparison and assessment of the effects of the intervention
level
degree of behavior change with different interventions (for example, high or low)
trend
direction of change of a behavior or behaviors (for example, increasing or decreasing)
variability
degree of change in a phenomenon over time
withdrawal design
removing a treatment to note whether it has been effective. in single-case experimental designs, a behavior is measured (baseline), an independent variable is introduced (intervention), and then the intervention is withdrawn. because the behavior continues to be measured throughout (repeated measurement), any effects of the intervention can be noted. also called reversal design
genotype
specific genetic makeup of an individual
multiple baseline
single-case experimental design in which measures are taken on two or more behaviors or on a single behavior in two or more situations. a particular intervention is introduced for each at different times. if behavior change is coincident with each introduction, this is strong evidence the intervention caused the change
phenotype
observable characteristics or behaviors of an individual
endophenotypes
genetic mechanisms that contribute to the underlying problems causing the symptoms and difficulties experienced by people with psychological disorders
human genome project
ongoing scientific attempt to develop a comprehensive map of all human genes
adoption studies
in genetics research, the study of first-degree relatives reared in different families and environments. if they share common characteristics, such as a disorder, this finding suggests that those characteristics have a genetic component
family studies
genetic studies that examine patterns of traits and behaviors among relatives
genetic linkage analysis
study that seeks to match the inheritance pattern of a disorder to that of a genetic marker. this helps researchers establish the location of the gene responsible for the disorder
proband
in genetics research, the individual displaying the trait or characteristic being studied
twin studies
in genetics research, the comparison of twins with unrelated or less closely related individuals. if twins, particularly monozygotic twins who share identical genotypes, share common characteristics such as a disorder, even if they were reared in different environments, this is strong evidence of genetic involvement in those characteristics
association studies
research strategies for comparing genetic markers in groups of people without a particular disorder
genetic marker
inherited characteristic for which the chromosomal location of the responsible gene is known
cohort
participants in each age group of a study with a cross-sectional design
cohort effect
observation that people of different age groups differ in their values and experiences
cross-sectional design
methodology to examine a characteristic by comparing individuals of different ages
longitudinal design
systematic study of changes in the same individual or group examined over time
retrospective information
literally “the view back;” data collected by examining records or recollections of the past. it is limited by the accuracy, validity, and thoroughness of the sources
cross-generational effect
limit on the generalizability of longitudinal research because the group under study may differ from others in culture and experience
sequential design
combination of the cross-sectional and longitudinal designs involving repeated study of different cohorts over time
informed consent
ethical requirement whereby research subjects agree to participate in a study only after they receive full disclosure about the nature of the study and their own role in it