4-1-14Psychology 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 behavioro 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?- Depressiono Why were these people suffering years after the incident?o William Styron – suffered crippling depression during the peak of his career- Eating behavioro Obesity or anorexia – why does this happen?o Neurobiology of eatingo 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: - A testable prediction stemming from the theory Observation:- Carefully measuring the phenomenon of interestTypes of observation:- Experimental – hallmark of science- Non-experimental (e.g. correlation)Experimental observation- Experiment:o An independent variable is manipulated while all other variables are held constant. Theeffects of the independent variable on some measured variable (the dependent variable) are carefully observedExample – - The disease “Pellagra”- Dr. Joseph Goldbergero Question: what causes the disease?o Hypothesis 1: bacterial infectiono Hypothesis 2: related to dieto Testing dietary hypothesis: Group A- Balanced diet Group B- Low protein, high carbohydrate diet Independent variable: diet  Dependent variable: number of sick people measure and healtho Results No illness in group A Many sick people in group Bo Found that the actual cause was vitamin B3 deficiency (Niacin) Example – - Drugs and depression- Independent variable: drug vs. no drug- Dependent variable: number of hours in bed per dayo Not directly measuring depression, have to rely on other indications of depression - Placeboo A treatment that has a psychological, but no biological effecto Designing an experiment to avoid placebo effect:- Benefits of experimental observationo Allows prediction of subsequent behavioro Allows identification of cause and effect relations between variables Manipulating the independent variable causes a change in the dependent variable- Confounding variableo A variable other than the independent variable that differentially affects the