Unit 0: AP Psychology

critical thinking

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

hindsight bias

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

Theory

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

Hypothesis

A testable prediction, often implied by a theory

operational definition

a carefully worded statement of the exact procedures used in a research study

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

case study

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

naturalistic observation

a descriptive technique of observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

survey

a descriptive technique for obtaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group

sampling bias

a flawed sampling process that produces an unrepresentative sample

Population

all those in a group being studied, from which samples may be drawn

random sample

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

Correlation

A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other.

correlation coefficient

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

Variable

anything that can vary and is feasible and ethical to measure

Scatterplot

a graphed cluster of dots, each of which represents the values of two variables

illusory correlation

perception of a relationship where none exists, or perception of a stronger relationship than actually exists

regression toward the mean

the tendency for extreme or unusual scores to fall back (regress) toward their average.

experiment

A research method in which an investigator manipulates one or more factors to observe the effect on some behavior or mental process

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.

random assignment

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

double-blind procedure

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

placebo effect

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.

independent variable

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

confounding variable

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

dependent variable

in an experiment, the outcome that is measured

Validity

the extent to which a test measures or predicts what it is supposed to

informed consent

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

Debriefing

the postexperimental explanation of a study, including its purpose and any deceptions, to its participants

descriptive statistics

numerical data used to measure and describe characteristics of groups. Includes measures of central tendency and measures of variation.

Histogram

a bar graph depicting a frequency distribution

Mode

the most frequently occurring score(s) in a distribution

mean

the arithmetic average of a distribution, obtained 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

skewed distribution

a representation of scores that lack symmetry around their average value

range

the difference between the highest and lowest scores in a distribution

standard deviation

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

normal curve

the symmetrical bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean and fewer and fewer near the extremes

inferential statistics

numerical data that allow one to generalize- to infer from sample data the probability of something being true of a population

statistical significance

how likely it is that an obtained result occurred by chance

peer reviewers

scientific experts who evaluate a research article's theory, originality, and accuracy

falsifiable

the possibility that an idea, hypothesis, or theory can be disproven by observation or experiment

social desirability bias

bias from people's responding in ways they presume a researcher expects or wishes

self-report bias

bias when people report their behavior inaccurately

single-blind procedure

An experimental procedure in which the research participants are ignorant about whether they have received the treatment or a placebo

experimenter bias

bias caused when researchers may unintentionally influence results to confirm their own beliefs

quantitative research

a research method that relies on quantifiable, numerical data

qualitative research

a research method that relies on in-depth, narrative data that are not translated into numbers

effect size

the strength of the relationship between two variables. The larger the effect size, the more one variable can be explained by the other

percentile rank

the percentage of scores that are lower than a given score