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: People should use this product because it will be beneficial to their health

Science vs Pseudoscience

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:

The Scientific Method 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

We analyze the data and reject or accept our hypothesis

Statistical Analysis

Correlations

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

Statistical Analysis

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

Research Ethics The Belmont Report –Summarizes the basic ethical principles that guide the conduct of biomedical and behavioral research –Originally published in 1979 Developed and published in response to the Tuskegee Syphilis Study

Basic Ethical Principles Respect for Persons –Respect for a persons right to make decisions based on adequate information –Protect those who are unable to make decisions for themselves Beneficence –Do NO harm –Maximize possible benefits while minimizing potential costs Justice –All people should be treated equally

Applications Informed consent –Information (full disclosure vs deception) –Comprehension (competence) –Voluntariness (non-coercive) Assessment of Risks and Benefits –Is the research justified? Selection of Participants –Procedures for selecting must be faired and unbiased

Applications Institutional Review Boards –Research watchdogs whose job it is to enforce the ethical principles –Include representatives from the research and lay communities; also experts in the field e.g., prisoner advocates; child psychologists; etc.