Science of Psychology Part II Critical Thinking and the Scientific Method What s wrong with human intuition What is a scientific attitude The Scientific Method Correlation vs Causation Limits of Intuition and Common Sense Intuition and common sense can be faulty Common errors in thinking 1 Hindsight bias I knew it all along 2 Overconfidence we think we know more than we really do They couldn t hit an elephant at this dist Other errors in thinking 3 The Availability Bias recall vivid examples 4 Confirmation bias looking for evidence that supports your theory while ignoring contradictory evidence The Scientific Attitude Approach the world with curious skepticism What do you mean How do you know Show me the evidence Requires humility We may have to reject our own ideas Critical thinking Thinking without blindly accepting arguments and conclusions In our everyday lives How do they know that Where is the evidence Are there other explanations Essentially question things The Scientific Method A process of evaluating claims about the world But first A video Testing Therapeutic Touch The Scientific Method 1 Perceive a question 2 State a clear theory 3 Form hypotheses 4 Test those hypotheses by Collecting Data 5 Evaluate the theory draw conclusions 6 Share Report the results Publish them in a journal The Scientific Method Theory an organized set of principles that describes explains and predicts behavior A good theory Organizes many observations Makes clear predictions Hypothesis a testable prediction derived from a theory The Scientific Method Data Collection Laboratory research research conducted in an environment that can be carefully controlled Field research research conducted in real world settings Naturalistic Observation How do we know if our data supports our theory Statistics mathematics used to analyze data Summarize data Make interpretations about data 3 Research Strategies Part 1 Descriptive in your book p 26 29 Correlational Experimental Correlational Research Are two or more factors naturally associated Correlation coefficient r statistical measure of relationship Range from 1 00 to 1 00 Positive correlations are those above 0 Negative correlations are those below 0 No relationship 0 Correlational Research As one variable goes up the other goes up As one variable goes up the other goes too DOWN NO relationship between variables Example Is this a positive negative or zero correlation Amount of time spent lifting weights Muscle mass A B C Example Is this a positive negative or zero correlation Temperature Amount of clothing worn A B C Example Is this a positive negative or zero correlation Green Lawns Ice Cream Eating A B C This illustrates the SPURIOUS CORRELATION Spurious adj 1 outwardly similar or corresponding to something without having its genuine qualities 2 of falsified or erroneously attributed origin In a spurious correlation things can be correlated but the correlation is due to a 3rd variable that you DON T KNOW ABOUT So in this example the 3rd variable is Season i e Summer This brings up the issue of causality Do green lawns really CAUSE someone to eat Ice cream Is correlation the same thing as causation NO Correlation and Causation Three ways to interpret correlations A B Watching violent TV might cause children to be more aggressive B A C A B Children that are more aggressive are more likely to watch more violent TV Neglectful parenting could be a cause of both A variable MUST meet these 3 criteria to be considered CAUSAL 1 Cause must come BEFORE the effect 2 There MUST be a correlation 3 The causal relationship must be NONSPURIOUS Remember spurious correlations If it is spurious its NOT CAUSAL Take home points 1 Psychology is the science of behavior and mental processes 2 Common sense and intuition are often incorrect 3 We must take a scientific approach and test our ideas 4 Correlation DOES NOT equal causation Science of Psychology Part 3 Experimentation Statistical Reasoning Ethics Experimentation Definition Creating a situation where you 1 Manipulate change one variable 2 Keep other variables constant Independent Variable The variable s that you change or manipulate Dependent Variable The outcome variable that changes due to the IV Control Variable The variable s that you keep the same Defining your Variables How would you define Sleepiness Success Defining your Constructs Conceptual Definition what people think a word means what you find in a dictionary Too vague for scientific research Not everyone agrees on the definition Operational Definition defines a concept by saying precisely how it is measured in a given research study Allows others to know how you measured this variable in your study Defining your Construct Sleepiness Conceptual definition feeling tired needing sleep Operational Definition A person who has slept less than 4 hours in the past 24 hours Experimental Research Random Sampling from a population of interest Participants are randomly assigned to a condition experimental or control Minimizes pre existing differences Everyone has the same chance of being in a condition Example Video Game Violence People who play many violent Video Games tend to be more aggressive To conduct an experiment Bring People into the lab Let them play a video game Violent Nonviolent Measure aggressive acts Statistical Reasoning We use statistics to organize summarize and make inferences from data Statistical Reasoning Making Inferences We are looking for a meaningful difference How likely is it that the result would have occurred by chance Statistically significant If the results could have occurred by chance 5 or fewer times out of 100 Often written as p 05 Ethics Is it ethical to experiment on people Is psychology dangerous The Ethical Standard What are the benefits What are the risks Benefits Risks A Little History Tuskegee Syphilis Study 1932 1972 History Tuskegee Experiment 600 African American men 399 had syphilis 201 did not Told that they were being studied for bad blood Denied treatment Penicillin was invented in 1947 Is This Ethical Participants had given their consent But they had been mislead about the purpose And they were not given the choice to quit Researchers must get informed consent from their participants beforehand Ethics Rights and well being People come first research second Informed consent make an informed decision Deception must be justified Withdraw from the study at anytime Protected from risk or told explicitly what they are