4 1 14 Psychology as a science Natural sciences chemistry physics Social sciences psychology sociology Is psychology less important than natural science Criteria for judging a science o How important are the phenomena Kitty Genovese Woman was stalked and stabbed multiple times and no witnesses called police Phenomena for psychologists to study Violence and aggressive behavior o What made this person engage in this horrific way Why was there no altruistic acts helping behavior o Why did no one help or intervene Depression o Why were these people suffering years after the incident o William Styron suffered crippling depression during the peak of his career Eating behavior o Obesity or anorexia why does this happen o Neurobiology of eating o How adequate are the tools Magnetic resonance imaging MRI Structural scans produces detailed images of brain tissue Functional scans shows what parts of the brain are active during some task ex listening to language o How good are the theories Is psychology a real science o Scientific method Testing hypotheses which stem from theories through careful observation Theory A set of claims that explains some phenomenon and that predicts how the phenomenon will behave under certain conditions Hypothesis Observation A testable prediction stemming from the theory Carefully measuring the phenomenon of interest o An independent variable is manipulated while all other variables are held constant The effects of the independent variable on some measured variable the dependent variable are carefully observed Types of observation Experimental hallmark of science Non experimental e g correlation Experimental observation Experiment Example The disease Pellagra Dr Joseph Goldberger o Question what causes the disease o Hypothesis 1 bacterial infection o Hypothesis 2 related to diet o Testing dietary hypothesis Group A Group B Balanced diet Low protein high carbohydrate diet Independent variable diet Dependent variable number of sick people measure and health Results Many sick people in group B No illness in group A Found that the actual cause was vitamin B3 deficiency Niacin o o o o o Example Drugs and depression Independent variable drug vs no drug Dependent variable number of hours in bed per day o Not directly measuring depression have to rely on other indications of depression Placebo o o Designing an experiment to avoid placebo effect A treatment that has a psychological but no biological effect Benefits of experimental observation Allows prediction of subsequent behavior Allows identification of cause and effect relations between variables Manipulating the independent variable causes a change in the dependent Confounding variable variable A variable other than the independent variable that differentially affects the dependent variable