Research Methods Flashcards

Independent variable (IV): what the researcher manipulates. Dependent variable (DV): what the researcher measures. Memory trick: the DV depends on what happens with the IV.

A variable other than the IV that could influence the DV, threatening the validity of the experiment. Good experimental design controls for confounds.

Randomly placing participants into experimental or control groups. It reduces pre-existing differences between groups, allowing researchers to infer causation.

Random sampling: selecting participants from the population (affects generalizability). Random assignment: placing selected participants into groups (affects causation claims).

Neither the participants nor the researchers interacting with them know who is in the experimental vs. control group. This controls for both placebo effects and experimenter bias.

When participants show improvement simply because they believe they are receiving treatment, not because of the treatment itself.

A precise description of how a variable will be measured or manipulated in a study. Example: defining 'aggression' as 'number of times a child hits a toy during a 10-minute observation.'

Correlation means two variables are related (they change together). Causation means one variable directly causes changes in another. Only experiments with random assignment can establish causation.

A strong negative correlation: as one variable increases, the other decreases. The closer to -1.0, the stronger the relationship. The sign indicates direction, not strength.

Reliability: consistency of results (do you get the same result each time?). Validity: accuracy (does the test measure what it claims to measure?).

Participants must be told about the study's purpose, procedures, risks, and their right to withdraw at any time before agreeing to participate. Required by APA ethical guidelines.

A study that follows the same group of participants over an extended period. Strength: tracks change over time. Weakness: expensive, participants may drop out (attrition).

A study comparing different age groups at a single point in time. Faster and cheaper than longitudinal, but cannot track individual change and may reflect cohort effects.

Mean: arithmetic average. Median: middle value when data is ordered. Mode: most frequent value. Median is best when data has extreme outliers.

A measure of how spread out scores are from the mean. Low SD means scores cluster near the mean; high SD means scores are widely dispersed.

There is less than a 5% probability that the results occurred by chance alone. This threshold is the standard in psychology for concluding that the IV affected the DV.

An in-depth investigation of a single individual or small group. Rich detail but cannot generalize to the broader population. Famous example: Phineas Gage.

Observing behavior in its natural environment without intervention. Provides ecological validity but lacks control over variables and cannot establish causation.

Experimental group: receives the treatment or manipulation. Control group: does not receive the treatment, serving as a baseline for comparison.

A symmetrical distribution where most scores fall near the mean, with fewer scores at the extremes. About 68% of scores fall within one standard deviation of the mean.