SCIENTIFIC METHOD Hypothesis is a testable prediction that

SCIENTIFIC METHOD Hypothesis is a testable prediction that lets us accept, reject, or revise a theory. It expresses a relationship between two variables. Theory is an explanation based on evidence that predicts behaviors or events.

To identify cause-and-effect relationships, we conduct experiments: –Directly vary a condition you might think affects behavior –Create two or more groups of subjects, alike in all ways except the condition you are varying –Record whether varying the condition has any effect on behavior

Applied Vs. Basic Research Applied Research has clear, practical applications. Ex--> Cancer research Basic Research explores questions that you may be curious about, but not intended to be immediately used. Ex--> Do old people still show affection?

Process

Terms Participants 1 or subjects Operational Definition 2 – Describes exactly what the variables are and how they are measured within the context of your study, e. g. define what you mean by sleep deprivation and driving performance. Population 3/Random Selection 4/Random Assignment 5 – The group involved in the study How you draw the sample (representative subset of population) of people from your study from a population Equal chances of inclusion How you assign the sample you draw different groups in your study is key fortoyour sample! psychology. ucdavis. edu/faculty_sites/sommerb/sommerdemo/sampling/types. htm

Terms Independent variable (IV)6/[Experimental group]7 Cause (what you are studying) Manipulated by the experimenter—IF Dependent variable (DV)8/[Control group]9 Effect (result of experiment) Measured by the experimenter—THEN Confounding Variable 10 Any variable not controlled; affects validity of results

Variables/Groups A variable is a condition that can change and might affect an experiment's outcome.

Variables

Terms Reliability 11/Validity 12 – Consistency/accuracy of measurements Replication 13 – The study can be duplicated, i. e. retest the hypothesis for procedural and outcome validity

Terms Experimental Bias 14 Unintentional effects experimenters may exert on their results Placebo Effect (leads to self-fulfilling prophecy)15 Experimental results caused by participant’s expectations, rather than actual treatment/condition Single-blind design 16/Double-blind design 17

Is the experiment statistically significant? That is, results gained would occur very rarely by chance alone. The difference must be large enough so that it would occur by chance in less than 5 experiments out of 100. A meta-analysis is a study of results of other studies to note similarities or patterns.

Drug Testing Studies designed to test the effectiveness of psychiatric or medical drugs often involve control groups in which subjects receive placebos. A placebo is a fake pill (sugar) or injection (saline). Placebos alter our expectations about our own emotional and physical reactions. If the placebo has any effect, it might be based on the power of suggestion, not chemistry. Self-fulfilling prophesy --> Changes in behavior that result from belief that one has ingested drugs. These expectancies then influence bodily activities.

Problems With Experiments/Solutions 1. Hindsight Bias--The tendency to believe, after learning the outcome, that you knew it all along. SO…there is a peer process review for experiments -and- there must be replication of the experiment. 2. False consensus effect--The tendency to overestimate, after learning the outcome, the extent to which their beliefs are typical of other beliefs. SO…there is a peer process review for experiments -and- there must be replication of the experiment. 3. Sample bias--The researcher predetermines the individuals who would participate in the experiment. SO. . . the researcher takes a random sample of the population to ensure that subgroups are represented proportionately.

Problems With Experiments/Solutions 4. Culture bias--The researcher assumes before the experiment that behaviors typical in one culture is typical in all cultures. SO. . . the researcher conducts the same study with different participants -or- a variety of ethnic/racial groups to determine if results are consistent. 5. Experiment bias--The researcher during the experiment displays body language/facial expressions or asks leading questions. SO. . . the researcher must use the appropriate research method.

Problems With Experiments/Solutions 6. Participant bias a. The researcher fails to take into account that a participant thinks they received medication when in reality they received a “fake pill” (placebo effect), then acts as if they are getting better (self-fulfilling prophecy) SO…the researcher sets up a single-blind experiment. --subjects have no idea whether they get real treatment or placebo SO…the researcher sets up a double-blind experiment. --subjects and researcher have no idea whether the subjects get real treatment or placebo (independent, neutral observer administers medicine) b. The participant changes their behavior because they are being observed (Hawthorne Effect) -or- accepts general characterizations of themselves and take them to be accurate (Barnum Effect) SO…the researcher must use the appropriate research method.