Unit 2 Experimentation Or How do psychologists get all that data to support their theories??? Psychological studies… Provide broad scientific information Explain what we do Tell us why we do it and tell us what changes occur over time!!! Accurate experiments… Give us solid information Allow psychologists to support theories about behavior Psychologists get data using… Surveys Case Studies Naturalistic observation Interviews Cross-sectional studies Longitudinal studies Most methods use… Sample groups (def.-group that represents a larger group) WHY??? Because its too expensive and takes too much time to get data from everyone in the whole wide world (even with the internet!!!) Why do psychologists need so many methods?? Because some work better than other in different situations Interview– face to face questions Survey- answer questions usually anonymously Advantage/disadvantage of each??? All psychologists use … The Scientific Method!!! Which is defined as the procedure to gather and interpret data BUT… EXPERIMENTATION Is the most used method by psychologists to gather data Experiments are a causal relationship between two variables or stated this way… IF X , THEN Y TWO types of experiments are… Laboratory – done in a lab (DUH!!!) Field – conducted out in the real world What are the advantages and disadvantages of each???? Elements of experiments: Hypothesis- an educated guess Subjects- people on which the experiment is conducted Variables- factors in the experiment (psychologists try to identify and control the variables) Types of Variables… Independent variable: has an effect on other variables (is messed with by the psychologist) Dependent variable: changes in an experiment so it is always measured!!! Hidden variables– unwanted variables that if not detected can change the results Exploring Cause & Effect Many factors influence our behavior. Experiments (1) manipulate factors that interest us, while other factors are kept under (2) control. Effects generated by manipulated factors isolate cause and effect relationships. Placebos… Has no active ingredients Sometimes called “the sugar pill” Can also work by the power of suggestion ( mind over matter) Up to 30% of people on placebos get better (who’d have thought that!!!) Subjects are put into groups.. Experimental group- gets the active ingredient (the IV) Control group- gets the placebo WHY?? So psychologists can compare the two !!! Bias can come from… “Hidden” or confounding variables Participant bias- when the subjects try to influence the results either deliberately or accidentally Researcher Bias- when the psychologist influences the results either deliberately or accidentally Results in “bad” data How do we know if the results are good????? Replication!!!! If an experiment can be repeated with the same results… the hypothesis is good. Correlation When one trait or behavior accompanies another, we say the two correlate. Indicates strength of relationship (0.00 to 1.00) Correlation coefficient Correlation Coefficient is a statistical measure of the relationship between two variables. r = + 0.37 Indicates direction of relationship (positive or negative) Correlation and Causation Correlation does not mean causation! or Illusory Correlation The perception of a relationship where no relationship actually exists. Parents conceive children after adoption. Do not conceive Adopt Confirming evidence Disconfirming evidence Do not adopt Disconfirming evidence Confirming evidence Michael Newman Jr./ Photo Edit Conceive Exploring Cause & Effect Many factors influence our behavior. Experiments (1) manipulate factors that interest us, while other factors are kept under (2) control. Effects generated by manipulated factors isolate cause and effect relationships. Experimentation A summary of steps during experimentation. Comparison Below is a comparison of different research methods.