Thinking Critically with Psychological Science

Theory

Organizes observations and predicts behaviour or events

Hypothesis

testable prediction. often implied by the theory

Operational definition

Carefully worded statement with exact procedures.

Replication

repeating the essence of a research study with different circumstances/ participants to see whether study findings extend to other circumstances.

correlation coefficient

a statistic representing how closely two variables vary together. how well can a change in one variable predict a change in another?

Descriptive research

a systematic, objective observation of people: to provide a clear, accurate picture. Nothing is manipulated.

correlational research

to detect naturally occuring relationships and assess how well one variable can predict another. Nothing is manipulated.

experimental research

to explore cause and effect. Involves manipulating variables.

Case study

examines one individual in depth. provides fruitful ideas. cannot be used to draw general conclusions

Naturalistic observation

records behaviour in their natural environment. Describes but does not explain behaviour. can be revealing.

Survey and interview

Examine many cases in depth. Caution: wording effect.

Random sampling

when surveying, survey a random sample of your target population for best results.

Scatterplot

each dot represents the value of 2 variables. must look at: slope of points (correlation), amount of scatter

illusory correlation

the perception of a relationship between two variables when only a minor or no relationship actually exists (fed by regression towards the mean)

Regression towards the mean

the tendency for extreme or unusual scores/ results to fall back (regress) towards someone’s personal average

Random assignment

when designing an experiment. Randomly assign people to each condition, effectively equalizing all the variables.

double blind procedure

eliminating bias by keeping secrets not only from the participants but also the doctors that are administering the placebo. separates actual treatment effects from possible placebo effects.

placebo effect

results caused by expectations/anticipation alone

Independent variable

factor that is manipulated and whose effect is being studied

Dependent variable

factor that is measured. may change when the independent variable is manipulated

Cofounding variable

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

mode

most frequently occurring score(s) in a distribution

mean

Avg of distribution. Add all scores and then divide by the number of scores.

Median

Middle score in a distribution. half of the scores are above it, half are below it. (write scores from lowest to highest and find the very centre value.)

range

difference between highest and lowest scores in a distribution

standard deviation

measuring how much your scores deviate (differ) from one another