Chapter Two: Research in Abnormal Psychology
Research in abnormal psychology is especially important: a wrong belief in the field leads to suffering
Schizophrenia: severe disorder that causes people to lose contact with reality
Lobotomies were believed to cure schizophrenia, but this was false
Wasn’t disproven until tens of thousands of people had been lobotomized
Caused irreversible brain damage that left patients withdrawn
What Do Clinical Researchers Do?
Clinical Researchers / Clinical Scientists try to discover universal laws / principles of abnormal psychological functioning using the scientific method
Clinical Practitioners assess, diagnose, and treat individual clients
seek an individualistic understanding of abnormal behavior
Clinical Researchers use three methods of investigation to form hypotheses
Case Study: focused on one individual
Correlational and experimental methods
Observe many individuals
Apply procedures uniformly (allows for replication)
Use statistical tests to analyze results
The Case Study
A detailed description of a person’s life and psychological problems
How Are Case Studies Helpful?
Can be a source of new ideas about behavior
Can challenge a theory’s assumptions
Can show the value of new therapeutic techniques
Can offer opportunities to study unusual problems
What Are the Limitations of Case Studies?
Reported by biased observers
Rely on subjective evidence
Low internal and external validity scores
Little basis for generalization
The Correlational Method
Correlation: the degree to which events / characteristics vary with each other
Correlational Method: research procedure used to determine correlation between variables
Subjects / Participants: people chosen for a study
Sample: collective name for participants in a sample
Must be representative of the larger population
Describing a Correlation
Line of best fit
Positive Direction: when variables change the same way. shows positive correlation
Negative Direction: when variables change in different ways. shows negative correlation
Unrelated variables: there is no consistent relationship between variables and no slope
Magnitude: How closely do the two variables correspond?
The closer the data points are to the line of best fit, the greater the magnitude between the variables
Correlation Coefficient
Positive / negative sign of the coefficient signifies direction
The number represents its magnitude - the closer it is to zero, the lower the relationship the variables have
When Can Correlations Be Trusted?
p < .05: Findings are statistically significant and are thought to reflect the larger population
The larger the magnitude of the correlation and the bigger the sample ➝ the more likely it is that a correlation will be statistically significant
What Are the Merits of the Correlational Method?
High external validity
Lack internal validity - describes the relationship between two variables, but doesn’t explain it
Variables can be correlated for any reason
Correlation doesn’t equal causation
The Experimental Method
Experiment: research procedure in which a variable is manipulated and the manipulation’s effect on another variable is observed
Independent variable
Dependent variable
Confounding variable
To guard against confounding variables, researchers should include a control group, random assignment, and a masked design
ex: bias
Control Group: A group of research participants who are not exposed to the independent variable under investigation
Experimental Group: The participants who are exposed to the independent variable
Statistical Significance: Indicates whether a participant’s improvement in functioning occurred because of treatment
Clinical Significance: Indicates whether the amount of improvement is meaningful in the person’s life
Random Assignment
Random Assignment: Any selection procedure that ensures that every participant in the experiment is as likely to be placed in one group as the other
Reduces the effects of preexisting differences
Masked / Blind Design
Avoids bias in experiments
Individuals are kept unaware of their assigned group
Double-Masked Design: Prevents against both patient bias and experimenter bias
Triple-Masked Design: Experimenters arrange for judges to assess and analyze the outcomes, and the judges are also kept unaware of group assignments
Alternative Research Designs
aka Mixed Designs / Quasi-experimental Designs
Designs that intermix elements of both correlational and experimental studies
Matched Designs
Researchers match the experimental participants with control participants who are similar in age, sex, socioeconomic status, etc.
Make use of groups that already exist in the world (ex: effects of abuse on children. splits children into groups of abused and not abused)
Violates the rule of random assignment
Matched design minimizes confounding variables caused by not using random assignment
Natural Experiments
Nature itself manipulates the independent variable while the experimenter observes the effects
Used for studying the psychological effects of natural disasters and other unpredictable events (floods, plane crashes, fires, etc)
Analogue Experiments
Experimenters induce lab participants to behave in ways that seem to resemble real-life abnormal behavior
Investigators can manipulate independent variables freely while avoiding ethical and practical limitations of clinical research
Often use animals as participants
Single-Subject Experiments
A single participant is observed both before and after the manipulation of an independent variable
Rely on baseline data (information gathered before any manipulations) that can be compared to data gathered after the manipulation of an independent variable
Longitudinal Studies
Researchers observe the same individuals on many occasions over a long period of time
Epidemiological Studies
Determine the incidence and prevalence of a problem in a particular population
Incidence: Number of new cases that emerge in a population during a given period of time
Prevalence: Total number of cases in the population during a given period
Includes both existing and new cases
Help researchers identify groups at risk for particular disorders
Cannot confirm causation alone
Protecting Human Participants
Institutional Review Boards: Committees of five or more members who review and monitor every study conducted at a research facility, starting at proposal
Rules:
Participants enlist voluntarily
Before enlisting, the participants are given informed consent
The participants can end their participation at any time
The benefits of the study outweigh its risks
Participants are protected from physical and psychological harm
Participants have access to info about the study
Participants have protected privacy
IRBs are flawed: Ethical principles can’t always be broken down into simple guidelines
Chapter Two: Research in Abnormal Psychology
Research in abnormal psychology is especially important: a wrong belief in the field leads to suffering
Schizophrenia: severe disorder that causes people to lose contact with reality
Lobotomies were believed to cure schizophrenia, but this was false
Wasn’t disproven until tens of thousands of people had been lobotomized
Caused irreversible brain damage that left patients withdrawn
What Do Clinical Researchers Do?
Clinical Researchers / Clinical Scientists try to discover universal laws / principles of abnormal psychological functioning using the scientific method
Clinical Practitioners assess, diagnose, and treat individual clients
seek an individualistic understanding of abnormal behavior
Clinical Researchers use three methods of investigation to form hypotheses
Case Study: focused on one individual
Correlational and experimental methods
Observe many individuals
Apply procedures uniformly (allows for replication)
Use statistical tests to analyze results
The Case Study
A detailed description of a person’s life and psychological problems
How Are Case Studies Helpful?
Can be a source of new ideas about behavior
Can challenge a theory’s assumptions
Can show the value of new therapeutic techniques
Can offer opportunities to study unusual problems
What Are the Limitations of Case Studies?
Reported by biased observers
Rely on subjective evidence
Low internal and external validity scores
Little basis for generalization
The Correlational Method
Correlation: the degree to which events / characteristics vary with each other
Correlational Method: research procedure used to determine correlation between variables
Subjects / Participants: people chosen for a study
Sample: collective name for participants in a sample
Must be representative of the larger population
Describing a Correlation
Line of best fit
Positive Direction: when variables change the same way. shows positive correlation
Negative Direction: when variables change in different ways. shows negative correlation
Unrelated variables: there is no consistent relationship between variables and no slope
Magnitude: How closely do the two variables correspond?
The closer the data points are to the line of best fit, the greater the magnitude between the variables
Correlation Coefficient
Positive / negative sign of the coefficient signifies direction
The number represents its magnitude - the closer it is to zero, the lower the relationship the variables have
When Can Correlations Be Trusted?
p < .05: Findings are statistically significant and are thought to reflect the larger population
The larger the magnitude of the correlation and the bigger the sample ➝ the more likely it is that a correlation will be statistically significant
What Are the Merits of the Correlational Method?
High external validity
Lack internal validity - describes the relationship between two variables, but doesn’t explain it
Variables can be correlated for any reason
Correlation doesn’t equal causation
The Experimental Method
Experiment: research procedure in which a variable is manipulated and the manipulation’s effect on another variable is observed
Independent variable
Dependent variable
Confounding variable
To guard against confounding variables, researchers should include a control group, random assignment, and a masked design
ex: bias
Control Group: A group of research participants who are not exposed to the independent variable under investigation
Experimental Group: The participants who are exposed to the independent variable
Statistical Significance: Indicates whether a participant’s improvement in functioning occurred because of treatment
Clinical Significance: Indicates whether the amount of improvement is meaningful in the person’s life
Random Assignment
Random Assignment: Any selection procedure that ensures that every participant in the experiment is as likely to be placed in one group as the other
Reduces the effects of preexisting differences
Masked / Blind Design
Avoids bias in experiments
Individuals are kept unaware of their assigned group
Double-Masked Design: Prevents against both patient bias and experimenter bias
Triple-Masked Design: Experimenters arrange for judges to assess and analyze the outcomes, and the judges are also kept unaware of group assignments
Alternative Research Designs
aka Mixed Designs / Quasi-experimental Designs
Designs that intermix elements of both correlational and experimental studies
Matched Designs
Researchers match the experimental participants with control participants who are similar in age, sex, socioeconomic status, etc.
Make use of groups that already exist in the world (ex: effects of abuse on children. splits children into groups of abused and not abused)
Violates the rule of random assignment
Matched design minimizes confounding variables caused by not using random assignment
Natural Experiments
Nature itself manipulates the independent variable while the experimenter observes the effects
Used for studying the psychological effects of natural disasters and other unpredictable events (floods, plane crashes, fires, etc)
Analogue Experiments
Experimenters induce lab participants to behave in ways that seem to resemble real-life abnormal behavior
Investigators can manipulate independent variables freely while avoiding ethical and practical limitations of clinical research
Often use animals as participants
Single-Subject Experiments
A single participant is observed both before and after the manipulation of an independent variable
Rely on baseline data (information gathered before any manipulations) that can be compared to data gathered after the manipulation of an independent variable
Longitudinal Studies
Researchers observe the same individuals on many occasions over a long period of time
Epidemiological Studies
Determine the incidence and prevalence of a problem in a particular population
Incidence: Number of new cases that emerge in a population during a given period of time
Prevalence: Total number of cases in the population during a given period
Includes both existing and new cases
Help researchers identify groups at risk for particular disorders
Cannot confirm causation alone
Protecting Human Participants
Institutional Review Boards: Committees of five or more members who review and monitor every study conducted at a research facility, starting at proposal
Rules:
Participants enlist voluntarily
Before enlisting, the participants are given informed consent
The participants can end their participation at any time
The benefits of the study outweigh its risks
Participants are protected from physical and psychological harm
Participants have access to info about the study
Participants have protected privacy
IRBs are flawed: Ethical principles can’t always be broken down into simple guidelines