Unit 1: Research Methods

AP psychology unit 1 with Miss Larochelle (HMHS)

hindsight bias

the tendency to believe, after learning of an outcome, that one would have foreseen it. (Also known as the I-knew-it-all-along phenomenon)

critical thinking

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

theory

an explanation using an integrated set of principles that organizes observations and products behaviors

hypothesis

a testable prediction, often implied by a theory

operational definition

a carefully worded statement of the exact procedures (operations) used in a research study. For example, human intelligence may be operationally defined as what an intelligence test measures

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

naturalistic observation

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

survey

a technique for ascertaining 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. (Note: Except for national studies, this does not refer to a country’s whole population)

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 variables change together, and thus of how well either variable predicts the other

correlation coefficient

a statistical index of the relationship between two variables (from -1.0 to +1.0)

scatterplots

a graphed cluster of dots, each of which represents the values of two variables. The slope of 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)

illusory correlation

the perception of a relationship where none exists

experiment

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

experimental group

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

control group

in an experiment, the group 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 groups by chance, thus minimizing preexisting differences between 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 variables

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

dependant variable

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

validity

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

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

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

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

informed consent

an ethical principle 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

single-blind procedure

participants don’t know which group they’re in but experiment staff do

self-report bias

our tendency to attribute our success to internal factors and our failures to external ones

social-desirability bias

when respondents give answers to questions that they believe will make them look good to others concealing their true opinions or experiences

experimenter bias

when the experimenter affects the results of their own study because of their expectations

effect size

how strong or weak a correlation is

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

meta-analysis

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

regression towards the mean

the tendency for extreme or unusual scores of events to fall back (regress toward the average)

peer reviewers

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

falsifiable

the capacity for some proposition, statement, theory or hypothesis to be proven wrong

variable

things that can be changed or altered, such as characteristics or values. Used in psychology experiments to determine if changes to one thing result in changes to another

percentile rank

the percentage of people in a norm group who scored lower than a particular individual on a test or assessment

standard deviation

a measure of dispersion or scatter in a data set relative to the data's central mean value

skewed distribution

one where frequency data is not spread evenly; the data is clustered at one end

normal curve

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 near the extremes

range

a measure of dispersion obtained by subtracting the lowest score in a distribution from the highest score