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Scientific Inquiry. What is Scientific Inquiry. Scientific inquiry is the system or procedure by which we seek to understand and explain behavior or the world around us . On a scale of 1 (don’t agree at all) to 5 (completely agree), how much do you agree with the following statement:
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What is Scientific Inquiry • Scientific inquiry is the system or procedure by which we seek to understand and explain behavior or the world around us
On a scale of 1 (don’t agree at all) to 5 (completely agree), how much do you agree with the following statement: People should use this product because it will be beneficial to their health
Canons of Science • Deterministic • events have meaningful causes • Empiricism • Good and bad ways to determine cause and effect • Making observations • Law of Parsimony (Occam’s Razor) • If two explanations are equally good, choose the simpler one
Canons of Science • Scientific theories must be: • Testable • Falsifiable • Define the circumstances under which your theory is wrong • Repeatable • Given the same set of circumstances, the same outcome should occur across observations
The Scientific Process • We make observations about a specific behavior • We develop a theory to account for the behavior • Theory a testable explanation for a set of factors or observations
The Scientific Process • We come up with a hypothesis based on our theory • (a statement that makes predictions about the outcome of a scientific study) • For Example: • If my theory is true under this situation, then X should happen • If, under this situation, X does not happen, then my theory is false
The Scientific Process • We conduct a controlled test of our hypothesis • We gather objective data • We define the variables of interest • We analyze the results • We accept or reject our hypothesis
Pseudoscience • What is it? • Presenting something as fact without sufficient scientific evidence • Not testable • How do we recognize it? • Use of scientific-sounding terms (e.g., quantum; vibrational) • E.G., ESP, Oxygenated Water, Accupuncture, Homeopathy, Feng Shui,
The Flying Spaghetti Monster Taken from: www.venganza.org
The Scientific Method Good Science
Good Science • We make observations • We observe and describe behavior or event • E.G., A man, who was leaving a bar, crashes into a parked car on the way home
Good Science • We develop a theory to explain the behavior or event • What theories can you come up with to account for this behavior and/or outcome? • He was drunk • Drunk driving causes accidents • Alcohol causes impairment of driving abilities • Talking on cell phones causes accidents (was he on a cell phone?) • The brakes on the car malfunctioned • The Flying Spaghetti Monster hates people who drive after leaving bars
Good Science • We come up with a hypothesis based on our theory • Remember: a good theory must generate hypotheses that are testable and falsifiable • We must be able to operationally define the variables of interest
Good Science • Operational Definitions • Define, concretely, how you will measure the variables of interest
Good Science • Theory: Alcohol impairs driving ability • Hypothesis 1: People who drink alcohol are more likely to get into car accidents than those who do not drink alcohol • Hypothesis 2: Alcohol slows down reaction time which causes more accidents • Hypothesis 3: Alcohol increases risk-taking while driving which causes more accidents
Good Science • We conduct a controlled test • We select a research design • We identify the population and select a sample • We define the variables of interest
Research Design • Non-experimental vs Experimental designs • Non-experimental – observe a single group of subjects at one point in time • Observational studies • Survey Studies • Experimental – involves multiple groups or multiple observations across time • Control – standard against which the effects of the experimental condition is compared
Research Design • External Validity • Can we generalize our findings from the experimental context to other people, in other places, at other times?
External Validity • Random Sampling • Identify Population • All people • All adults • All adults who drink alcohol • All adults who drive after drinking alcohol • Select Sample • Select sample from population of interest • Random • Stratified – representative of the population on key characteristics
Research Design • Internal Validity • Can we be confident that the observed outcomes are due to (caused by) our experimental treatment and NOT to some other cause?
Internal Validity • To help subjects “get in the mood,” the bartender played loud and upbeat music during the “drink alcohol” condition. No music was played during the “drink water” condition. • Confound – uncontrolled and/or unmeasured characteristic(s) that accounts for the observed findings
Research Design • Random Assignment • Place subjects at random into different control and experimental conditions • Goal is to ensure that potential confounds are equally represented in both groups • Not always possible, so how do we ensure internal validity?
Testing Hypotheses • Independent variable • Predictor Variable • Variable that is manipulated • Dependent Variable • Predicted variable • Variable that “depends on” or is affected by the independent variable • Operational definition • Concrete description of how your variables will be measured
Testing Hypotheses • Observation – a man leaves a bar and gets into a car accident • Hypothesis 1: Heavier drinkers take more risks while driving than lighter drinkers • Hypothesis 2: Individuals who are intoxicated take more risks while driving than individuals who are sober
Testing Hypotheses • Hypothesis 1 • IV: level of drinking is defined using the quantity frequency index • DV: Risk-taking is defined as • frequency of speeding (i.e., number of days per week that the individual drives 10 + miles over the speed limit) • Frequency of tailgating
Statistical Analysis Variance Explained
Testing Hypotheses • Hypothesis 2 • IV: Intoxication is defined as a BAC of .08 mg% or greater • DV: Risk-taking is defined through use of a simulated driving task as • amount of time spent speeding and • number of times passing cars on a double yellow line
Good Science • A theory becomes a law when • supporting evidence accumulates over multiple tests of the associated hypotheses and • it has never been proven false • E.g., the law of physics • Pseudoscientific claims cannot become laws
Ethical Issues • Informed Consent • Subjects must be fully informed about • Potential risks and benefits of participation • Exactly what the study involves • Deception • Deception can be used if necessary to test hypotheses • Participation is voluntary • Coercion is not acceptable