Variables Flashcards
What is the definition of a variable?
- Basically, things that vary. But, many formal definitions:
- Any characteristic, trait, or condition that can change or vary
- Characteristics or conditions that change or have different values for different
individuals - Characteristics, traits, or factors that can be measured or observed within
individuals
What are the types of variables in psychology?
- Well-defined, easily observed, and easily measured
Examples: Height, Marital status, Cannabis user, “Boomer” (people born between 1946 and 1964 - Intangible or abstract attributes
Examples: Motivation, Self-esteem, Stress
What is the measurement of the intangible or abstract?
When a variable cannot be observed or measured directly but is useful for describing and explaining behavior, we refer to this as a sConstruct (aka Hypothetical Construct)
What is a construct?
Constructs are Hypothetical entities created from theory and speculation
- They cannot be seen, but are assumed to exist
- They help explain and predict behavior in a theory
What are some typical constructs in psychology?
Intelligence
Honesty
Memory
Attention
What distinguishes science from pseudoscience?
Scientific research relies on evidence that is gathered from careful, systematic, and objective observations
How can we make our observations of a construct Objective?
Although its not the same “thing” as the construct, we ensure objectivity in measurement through the use of operational definitions
What is the definition of operational definition
A clear, concise, and replicable
procedure used to measure a construct
Can there be multiple operational definitions of the same construct?
Science often uses multiple definitions of the same construct
In developed areas of science, you will see many operational definitions for a construct!
There is not always agreement though…
- Emotional Intelligence: Trait vs. skill
- Rationality: Psychology vs. Economics
Operational definitions are generally revisited and updated based on evidence
- Side note: Disagreements can lead to great discoveries (e.g. behavioral economics)
How does science define stress?
An adaptive response to a perceived danger or threat that involves physiological, cognitive, affective, and behavioral components (NIMH)
- Holmes & Rahe (1967) – Different points per stressful event (e.g., changed jobs = 36 points, divorce = 73 points)
- Delongis et al., (1972) - Everyday stressors like misplacing things and being concerned about one’s weight.
- Cohen et al., (1983) - self-report measure that focuses on people’s feelings of stress (e.g., “How often have you felt nervous and stressed?”)
Is someone right/wrong? Is one measure better/worse than another?
What are the two general criteria for evaluating the quality of any measurement procedure?
Validity of measurement
Reliability of measurement
What is the validity of measurement?
The degree to which the measurement process measures the variable it claims to measure
What is the reliability of measurement?
The degree of stability or consistency of the measurement
What is face validity?
A measure superficially appears to measure what it claims to measure
What is concurrent validity?
A measure is correlated with a more established measure of the same construct
What is predictive validity?
Scores obtained from a measure accurately predict behavior according to a theory
What is construct validity?
Scores obtained from a measurement behave exactly the same as the variable itself
What is convergent validity?
Strong relationship between the scores obtained from two (or more) different methods of measuring the same construct
What is divergent validity?
Showing little or no relationship between the measurements of two different constructs
What is test-retest reliability?
Compares scores of two successive measurements of
the same individuals and correlates the scores
What is inter-rater reliability?
Agreement between two observers who simultaneously record measurements of the behaviors
What is the relationship between reliability and validity?
Reliability is a prerequisite for validity
- A measurement procedure cannot be valid unless it is reliable
It is not necessary for a measurement to be valid for it to be reliable
- Consistency of measurement is no guarantee of validity
What is the nominal scale?
Represents qualitative differences in the variable measures
What is the ordinal scale?
Represents differences in a series of ranks
What is the interval scale?
Consist of a series of equal intervals like the inches on a ruler but lacks a true zero. Rather, the zero point is arbitrary and does not represent a complete absence of the variable
What is a ratio scale?
Consist of a series of equal intervals but also has a true zero value
What numbers do we use in our measurements?
Nominal scale
Ordinal scale
Interval scale
A ratio scale
What are the 3 modalities of measurement?
Self-report
Physiological measures
Behavioral measures
What is a self-report measure?
Self-report measures ask participants direct questions to study behavior
- Provides a direct measure; validity is dubious
What is physiological measures based on?
Physiological measures are based on manifestations of the underlying construct (i.e brain activity during an MRI)
- Provide objective measures
- Require expensive equipment; may not provide valid measures of constructs
What are behavioral measures based on?
Behavioral measures are based on overt behaviors that can be observed and measured
- Provide researchers with a vast number of options
- Possible to select the behavior(s) that seem to be best for defining and measuring the construct
- Behaviors may be only a temporary or situational indicators of an underlying construct
What are problems with measurements in general?
Artifact
Experimenter bias
Demand characteristics
The Hawthorne effect
- Essentially, anything that is not part of the intended manipulation but affects the outcome of the study is an artifact
What is an artifact?
A non-natural feature that can unintentionally influences and distort the results of a study
What are the examples of an artifact?
Experimenter bias: measurements are influenced by the experimenter’s expectations regarding the outcome of the study
Demand characteristics: Participants guess the study’s aim and behave accordingly
The Hawthorne effect: participants change their behavior due to being observed
