Chapter 2 - The Measure of Mind

The Scientific Methods of Psychology

Science

A method for learning about reality through systematic observation and experimentation

Objectivity

The practice of basing conclusions on facts, without the influence of personal emotion and bias

Confirmation bias

The tendency to notice and remember instances that support your beliefs more than instances that contradict them

Critical thinking

The ability to think clearly, rationally, and independently

Theory

A set of facts and relationships between facts that can explain and predict related phenomena

Hypothesis

A proposed explanation for a situation, usually taking the form “If A happens, then B will be the result.”

Replication

Repeating an experiment and producing the same results

Descriptive method

Research methods designed for making careful, systematic observations

Case study

An in-depth analysis of the behavior of one person or a small number of people

Naturalistic observation

An in-depth study of a phenomenon in its natural setting

Survey

A descriptive method in which participants are asked the same questions

Sample

A subset of a population being studied

Population

The entire group from which a sample is taken

Correlation

A measure of the direction and strength of the relationship between two variables

Variable

A factor that has a range of values

Measure

A method for describing a variable’s quantity

Third variable

A variable that is responsible for a correlation observed between two other variables of interest

Experiment

A research method that tests hypotheses and allows researchers to make conclusions about causality

Independent variable

An experimental variable controlled and manipulated by the experimenter, the “if A happens” part of a hypothesis

Dependent variable

A measure that demonstrates the effects of an independent variable, the “result” part of a hypothesis

Control group

A group that experiences all experimental procedures, with the exception of exposure to the independent variable

Experimental group

A group of participants who are exposed to the independent variable

Random assignment

The procedure in which each participant has an equal chance of being placed in any group in an experiment

Confounding variable

Variables that are irrelevant to the hypothesis being tested but can alter a researcher’s conclusions

Operationalization

Defining variables in ways that allow them to be measured

Meta-analysis

A statistical analysis of many previous experiments on a single topic

Publication bias

The possibility that published studies are not representative of all work done on a particular phenomenon

Cross-sectional study

An experimental design for assessing age-related changes in which data are obtained simultaneously from people of differing ages

Longitudinal study

An experimental design for assessing age-related changes in which data are obtained from the same individuals over a long period of time

Mixed longitudinal design

A method for assessing age-related changes that combines the cross-sectional and longitudinal approaches by observing a cross-section of participants over a shorter period than is used typically in longitudinal studies

Reliability

The consistency of a measure, including test-retest, interrupter, inter-method, and internal consistency

Validity

A quality of a measure that leads to correct conclusions (i.e., the measure evaluates the concept that it was designed to do)

Descriptive statistics

Statistical methods that organize data into meaningful patterns and summaries, such as finding the average value

Inferential statistics

Statistical methods that allow experiments to extend conclusions from samples to larger populations

Generalize

To extend conclusions to larger populations outside your research sample

Null hypothesis

A hypothesis stating the default position that there is no real difference between two measures

Statistical significance

A standard for deciding whether an observed result is likely in the event the null hypothesis is true

Informed consent

Permission obtained from a research participant after the risks and benefits of an experimental procedure have been thoroughly explained