AP Psychology Research Methods

Hindsight Bias

The tendency to believe, after learning an outcome, that one would have foreseen it

Double Blind Procedure

An experimental procedure in which both the research participants and the research staff are ignorant about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies

Independent Variable

The experimental factor that is manipulated--the variable whose effect is being studied

Dependent Variables

The outcome factor -- the variable that may change in response to manipulations of the independent variable

Mode

The most frequently occurring score(s) in a distribution

Mean

The arithmetic average of a distribution, obtaining by adding the scores and then dividing by the number of scores

Median

The middle score in a distribution--half the scores are above it and half are below it

Standard Deviations

A computed measure of how much scores vary around the mean score

Random Assignment

Assigning participants to experimental and control conditions by chance ,thus minimizing preexisting differences between those assigned to the different groups

Random Sampling

A sample that fairly represents a population because each member has an equal chance of inclusion

Scatter plot

A graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation

Illusory Correlation

The perception of a relationship where none exists

Case Study

An observation technique in which one person is studied in depth in the hope of revealing universal principles

Survey

A technique for ascertaining the self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them

Naturalistic Observation

Observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

Correlation

A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other. The correlation coefficient is the mathematical expression of the relationship, ranging from -1 to +1

Experiment

A research method in which an investigator manipulates one or more factors (independent variables) to observe the effects on some behavior or mental process (the dependent variable). By random assignment of participants, the experimenter aims to control other relevant variable

Replication

Repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances

Statistical Significance

A statistical statement of how likely it is that an obtained result occurred by chance

Operational Definition

A statement of the procedures used to define research variables. Ex human intelligence -- what an intelligence test measures.

Critical Thinking

thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions.

Theory

an explanation using an integrated set of principles that organizes and predicts observations

Hypothesis

a testable prediction, often implied by a theory

Population

all the cases in a group, from which samples may be drawn for a study

Sample

items selected at random from a population and used to test hypotheses about the population

Correlation Coefficient

a statistical index of the relationship between two things (from -1 to +1)

Placebo

experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent.

Placebo Effect

any effect that seems to be a consequence of administering a placebo

Experimental Group

in an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable.

Control Group

in an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.

Confounding Variable

a factor other than the independent variable that might produce an effect in an experiment.

Range

the difference between the highest and lowest scores in a distribution

Normal Curve/distribution

a symmetrical, bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean (68% fall within one standard deviation of it) and fewer near the extremes

Inferential Statistics

numerical methods used to determine whether research data support a hypothesis or whether results were due to chance

Culture

the enduring behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next

Informed Consent

an ethical principle requiring that research participants be told enough to enable them to choose whether they wish to participate

Debriefing

the post-experimental explanation of a study, including its purpose and any deceptions, to its participants

Kenneth and Mamie Clark

Used dolls to study children's attitude towards race. Their findings were used in the Brown vs. Board trial.

Daniel Kahneman

an Israeli psychologist and Nobel laureate, who is notable for his work on the psychology of judgment and decision-making, behavioral economics and hedonistic psychology.

longitudinal study

researchers follow the same subjects over an extended period of time.

Amos Tversky

A key figure in the discovery of systematic human cognitive bias

confirmation bias

experimenter might consciously or unconsciously look to confirm what they already believe about their hypothesis

Null hypothesis

Researchers work to reject, nullify or disprove the null hypothesis. Researchers come up with an alternate hypothesis, one that they think explains a phenomenon, and then work to reject the null hypothesis.

confidentiality

researchers may not release or publish the names of anyone participating in the experiment.

protection of participants

All participants are protected from physical mental and emotional harm.

Right to discontinue

Participants have the right to end their participation during any phase of an experiment.

minimum of deception

Researchers have an obligation to avoid deceiving participants whenever possible.

framing

the way questions are worded can dramatically impact the results of your survey.

Descriptive Statistics

describe the basic features of the data in a study. They provide simple summaries about the sample and the measures.

Skewed distribution to the left

Skewed distribution to the right

variance

measures how far a data set is spread out. The technical definition is "The average of the squared differences from the mean."

Mary Whiton Calkins

Denied a PhD by Harvard though she met the doctoral requirements, but later became first female president of the APA.

Margaret Floy Washburn

First woman to receive a PhD in psychology. Later became the 2nd female president of the APA.

Francis Sumner

First African American man to receive a PhD in psychology in 1920.

Inez Prosser

First African American woman to receive a PhD in psychology in 1933.

Edward Titchener

Studied with Wilhelm Wundt prior to becoming a psychology professor. His ideas created the basis for a school of thought called structuralism.