Psychology: from Inquiry to Understanding: Chapter 2

Prefrontal Lobotomy
Surgical procedure that severs fibers connecting the frontal lobes of the brain from the underlying thalamus.

Heuristic
Mental shortcut or rule of thumb that helps us to streamline our thinking and make sense of our world.

Naturalistic Observation
Watching behavior in real-world settings without trying to manipulate the situation.

External Validity
Extent to which we can generalize findings to real-world settings.

Internal Validity
Extent to which we can draw cause and effect inferences from a study.

Case Study
Research design that examines one person or a small number of people in depth, often over an extended time period.

Existence Proof
Demonstration that a given psychological phenomenon can occur.

Random Selection
Procedure that ensures every person in a population has an equal chance of being chosen to participate.

Reliability
Consistency of Measurement

Validity
Extent to which a measure assesses what it purports to measure.

Response Set
Tendency of research participants to distort their responses to questionnaire items.

Correlational Design
Research design that examines the extent to which two variables are associated.

Scatterplot
Grouping of points on a two-dimensional graph in which each dot represents a single person’s data.

Illusionary Correlation
Perception of a statistical association between two variables where none exists.

Experiment
Research design characterized by random assignment of participants to conditions and manipulation.

Control Group
In an experiment, the group of participants that doesn’t receive the manipulation.

Independent Variable
Variable that an experimenter manipulates.

Dependent Variable
Variable that an experimenter measures to see whether the manipulation has an effect.

Operational Definition
A working definition of what a researcher is measuring.

Placebo Effect
Improvement resulting from the mere expectation of improvement.

Blind
Unaware of whether one is in the experimental group or control group.

Experimenter Expectancy Effect
Phenomenon in which researchers’ hypotheses lead them to unintentionally bias the outcome of a study.

Double-Blind
When neither researchers nor participants are aware of who’s in the experimental or control group.

Demand Characteristics
Cues that participants pick up from a study that allow them to generate guesses regarding the researcher’s hypothesis.

Informed Consent
Informing research participants of what is involved in a study before asking them to participate.

Statistics
Application of mathematics to describing and analyzing data.

Descriptive Statistics
Numerical characterizations that describe data.

Central Tendency
Measure of the “central” scores in a data set, or where the group tends to cluster.

Mean
Average; a measure of central tendency

Median
Middle score in a data set; a measure of central tendency

Mode
Most frequent score in a data set; a measure of central tendency.

Variability
Measure of how loosely or tightly bunched scores are.

Range
Difference between the highest and lowest scores; a measure of variability.

Standard Deviation
Measure of variability that takes into account how far each data point is from the mean.

Inferential Statistics
Mathematical methods that allow us to determine whether we can generalize findings from our sample to the full population.