Unit 0 AP Psychology 2024

Experimental research

a research method in which one or more independent variables are systematically varied to determine their effect on a dependent variable

Independent variable (IV)

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

Dependent variable (DV)

The variable that is measured by the researcher. Any result/change on the this should be caused by the change in the variable being manipulated

Confounding variables

in an experiment, a factor other than the factor being studied that might influence a study's results

Random assignment

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

Population

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

Sample

a subset of the population

Random sampling

a technique that provides a sample in which each member has an equal chance of inclusion

Representative samples

a small quantity of something that accurately reflects the larger entity

Convenience samples

samples of individuals who are the most readily available

Sampling bias

a flawed sampling process that produces an unrepresentative sample

Generalizability

the extent to which we can claim our findings inform us about a group larger than the one we studied

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.

Placebo group

a control group in an experiment that is exposed to an inert treatment, such as a sugar pill

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.

Single-blind procedure

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

Double-blind procedure

an experimental procedure in which both the research participants and the research staff 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

Case study

a non-experimental technique in which one individual or group is studied in depth in the hope of revealing universal principles

Correlation

A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other. (DOES NOT EQUAL CAUSATION)

Positive correlation

a relationship between two variables in which both variables either increase or decrease together

Negative correlation

the relationship between two variables in which one variable increases as the other variable decreases

Directionality problem

an issue encountered in correlational studies; the researchers find a relationship between two variables, but they cannot determine which variable MAY have influenced changes in the other variable

Third-variable problem

A problem that occurs when the researcher cannot directly manipulate variables; as a result, the researcher cannot be confident that another, unmeasured variable is not the actual cause of differences in the variables of interest.

Scatterplots

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 (little scatter indicates high correlation).

Correlation coefficient

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

Quantitative measures (e.g. Likert scales)

research that gathers quantifiable, numerical data (e.g., rate on a scale from 1-10)

Qualitative measures (e.g. structured interviews)

research that gather in-depth, narrative data that are not translated into numbers (e.g., information gathered from open-ended questions)

Surveys

a non-experimental technique from obtaining the self-reported attitudes of behaviors of a particular group, usually by questioning a representative, random sample of the group

Framing

the way an issue is posed; this can significantly affect decisions and judgments.

Social desirability bias

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

Self-report bias

bias when people report their behavior inaccurately

Meta-analysis

a statistical procedure for analyzing the results of multiple studies to reach an overall conclusion

Naturalistic observation

a non-experimental technique of observing and recording behavior in naturally occurring situations without traying to manipulate or control the situation

Hypothesis

A testable prediction, often implied by a theory

Falsifiability

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

Operational definitions

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

Peer review

A process by which the procedures and results of an experiment are evaluated by other scientists who are in the same field or who are conducting similar research.

Ethical guidelines

suggested rules for acting responsibly and morally when conducting research or in clinical practice

Institutional Review Board (IRB) (for human and non-human research)

A committee at each institution where research is conducted to review every experiment for ethics and methodology.

Informed consent

giving potential participants enough information about a study to enable them to choose whether they wish to participate

Informed assent

a process that allows minors to agree to participate in research studies, clinical trials, or other activities, minors are considered a vulnerable population and can't provide consent in the full sense of the word.

Protection from harm

During a research study, participants should not experience negative physical or psychological effects, such as physical injury, lowered self-esteem, or embarrassment

Confidentiality of participants

protection of the privacy of research participants by prohibiting disclosure of protected information for non-research purposes to anyone not connected with the research except in specific situations

Minimal deception

the use of a little deception as possible if necessary for the success of a research study, will not cause lasting harm and is absolutely necessary.

Confederates

a person who is working with the experimenter and posing as a part of the experiment, but the subjects are not aware of this affiliation

Debriefing

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

Central tendency (mean, median, mode)

The average of a set of numbers, a measure of center in a set of numbers, the most frequently occurring scores

Measures of variation (range and interpret standard deviation)

statistics of how far away the values in the observations (data points) are from each other (the difference between the largest and smallest data point, a computed measure of how much scores vary around the mean)

Normal curve (percentages and percentiles)

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

Skewed distributions

a representation of scores that lack symmetry around their average value (can be positive or negative)

Bimodal distributions

frequency distribution in which there are two high points rather than one

Regression toward the mean

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

Statistical significance

a statistical statement of how likely it is that an obtained result (such as the difference between two samples) occurred by chance, assuming there is no difference between the populations being studied

Effect size

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

Confirmation bias

a tendency to search for information that supports our preconceptions and to ignore or distort contradictory evidence

Hindsight bias

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

Overconfidence

the tendency to be more confident than correct—to overestimate the accuracy of our beliefs and judgments.

mean

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

mode

the most frequently occurring score(s) in a distribution

median

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

percentile rank

the percentage of scores that are lower than a given score

normal curve

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

inferential statistics

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

statistical significance

p value is less than 0.05 (5%)