The Research Process: How We Find Things Out

The Scientific Method What are the components of the scientific method? Specify a problem Systematic observation Data Replication Form a hypothesis Test the hypothesis Operational definition Formulate a theory Test the theory

The Scientific Method What is the relationship between theory, prediction (hypothesis), and data? Prediction Theory Data Theory development, validation, correction

Descriptive Research Naturalistic observation Case studies Surveys Allows one to see patterns in the real world Case studies Focus on a single interesting case in detail Surveys A set of questions put to a number of participants about their beliefs, attitudes, preferences, or activities

Correlational Research Studies where the relationships between two or more variables are measured but not manipulated Examples Family income and IQ score Height and shoe size MAO levels and thrill seeking

Correlation Strength and direction

Correlation Research Strength Weakness Can study variables that cannot be manipulated Weakness Correlation does not imply causation

Designing Experiments: Independent Variable The aspect of a situation that is intentionally varied while another aspect is measured Examples Amount of practice allowed Participants randomly assigned so that they receive a drug or placebo Present visual or auditory stimuli Temperature of room

Designing Experiments: Dependent Variable The aspect of a situation that is measured while the independent variable is changed Examples Number of words recalled Speed of response Number of cigarettes smoked Electrical activity in the brain

Designing Experiments: Effects The difference in the dependent variable that is due to changes in the independent variable Examples Drug X impairs short-term memory Visualization improves athletic performance Practice improves reading speed

Experiments Experimental group Control group Random assignment Strength Rigorous control, causal inferences Weakness Not all variables can be manipulated

Quasi-Experiments Like experiments but without random assignment Strength Real-world phenomena that cannot be studied in experiments Weakness Lack of control means limited causal inferences

Being a Critical Consumer Reliability Validity Face validity Content validity Criterion validity Construct validity

Bias and Expectation Response bias Sampling bias Experimenter expectancy effects Double-blind design

Pseudopsychology Unsupported opinion pretending to be psychological science What makes a discipline a science? Is it the topic of study? Is it the method of study? Examples ESP Astrology

Statistics: Measuring Reality Benjamin Disraeli: “There are three kinds of lies: lies, damned lies, and statistics.” Be a critical statistics consumer; know the basics Two main types of statistics Descriptive Inferential

Descriptive Statistics Central tendency Mean Median Mode Normal distribution

Descriptive Statistics Variability Range Standard deviation Relative standing Percentile rank

Inferential Statistics Do patterns in measurement reflect true patterns or just chance variation? Statistical significance A measured relationship is not simply due to chance Expressed in terms of probability (p) Psychologists generally view a finding as “statistically significant” if it has no more than a 5% probability of occurring by chance

Inferential Statistics Sampling Population Sample Sampling error Meta-analysis Population Sample

Lying with Statistics Selective reporting Which statistics are reported and which are omitted?

Lying with Graphs Shortening the Y axis

Lying with Graphs Lengthening the Y axis

Lying with Graphs “Tricking” the visual system Using 3-D graphics to exaggerate size Changing width with height Plotting transformed data

Reading Research Reports QALMRI method Question Alternatives Logic of the study Method Results Inferences

Writing Research Papers Introduction Method Results Discussion