Honours Seminar Lecture 3: Critical Thinking

Scientific Reasoning Falsifiable Falsifiable Why am I not necessarily right? Why am I not necessarily right? How often does someone argue against themselves? How often does someone argue against themselves? Logic Logic People do not think logically People do not think logically Comprehensiveness: Comprehensiveness: Does it account for all the data, e.g. 110 year old smoker, thus smoking does not cause problems Does it account for all the data, e.g. 110 year old smoker, thus smoking does not cause problems Honesty – are we objective Honesty – are we objective E.g., international students go to the library together E.g., international students go to the library together

More on Scientific Reasoning Replicability Replicability True effects have been systematically replicated True effects have been systematically replicated Sufficiency Sufficiency Burden of proof is on the claimant, e.g., drugs Burden of proof is on the claimant, e.g., drugs Extraordinary claims neede extraordinary evidence Extraordinary claims neede extraordinary evidence E.g., crop circles E.g., crop circles General contrariness: Some people want to argueanything General contrariness: Some people want to argueanything Strength of prevailing views of science Strength of prevailing views of science

Antiscientific beliefs Post-modernism Post-modernism What is the colour Red? What is the colour Red? There is no such thing as a learning disability There is no such thing as a learning disability “What works is different for everybody” “What works is different for everybody” Bushmills cures sore throats Bushmills cures sore throats Probabilities are irrelevant individuals Probabilities are irrelevant individuals E.g., runner drops dead. People say “see, why run” E.g., runner drops dead. People say “see, why run” Science itself is bad Science itself is bad E.g., testing in schools E.g., testing in schools

Critical thinking Tries to function independently of preconceived notions of how the world functions Tries to function independently of preconceived notions of how the world functions Focuses on the simplest explanation of events Focuses on the simplest explanation of events Thinks of ways in which a conclusion may be at fault Thinks of ways in which a conclusion may be at fault Tries to think of ways to strengthen research designs to isolate an dependent variable Tries to think of ways to strengthen research designs to isolate an dependent variable

Trends in research designs Observational research Observational research Participant observation Participant observation Correlational research Correlational research Quasi-experimental research Quasi-experimental research Experimental research Experimental research Blind, Double-Blind Blind, Double-Blind Example: You wish to show that caffeine causes accelerated motor behaviour in students

Correlational research designs Direction of causality Example: A soccer ball is kicked. It goes up a certain height and is in the air a certain length of time. Does the height cause the time, or does the time cause the height? Example: A soccer ball is kicked. It goes up a certain height and is in the air a certain length of time. Does the height cause the time, or does the time cause the height? A causes B A causes B B causes A B causes A C causes A and B C causes A and B

The importance of experiments Random assignment should equate your groups on individual differences Random assignment should equate your groups on individual differences Self selection to groups means that non-random influences could account for the differences between the groups Self selection to groups means that non-random influences could account for the differences between the groups There are other problems with experiments: There are other problems with experiments: Diffusion of your treatment Diffusion of your treatment “Hypothesis guessing” “Hypothesis guessing” Attrition can result in loss of randomisation Attrition can result in loss of randomisation

Construct validity of measures What are you measuring? What are you measuring? Are you sure you are measuring what you are measuring? Are you sure you are measuring what you are measuring? Example: Example: Obese and non-obese people are in a waiting room Obese and non-obese people are in a waiting room Shelled and non-shelled peanuts are available Shelled and non-shelled peanuts are available Obese people eat more non-shelled peanuts Obese people eat more non-shelled peanuts How do you interpret these results? How do you interpret these results? Can you offer an alternative explanation for these results Can you offer an alternative explanation for these results

External validity Results may not generalise to other samples or populations Results may not generalise to other samples or populations Why? What non-random effects exist in your sample that may differ from others? Why? What non-random effects exist in your sample that may differ from others? Example: A study of reading conducted in Nova Scotia. Will it generalise to other provinces? Why or why not? Example: A study of reading conducted in Nova Scotia. Will it generalise to other provinces? Why or why not? Psychology students are recruited into a study to show that family disruption is related to well-being at university. Psychology students are recruited into a study to show that family disruption is related to well-being at university.

Newspaper task: Identify a testable hypothesis and translate the research questions into an experimental research design Observational research Observational research Participant observation Participant observation Quasi-experimental research Quasi-experimental research Experimental research Experimental research Blind, Double-Blind Blind, Double-Blind

Hypotheses Sarah, Kelly, Tina, Kate: Experimental Sarah, Kelly, Tina, Kate: Experimental Does an Emergency Response Program work, compare 3 kinds of schools randomly selected Does an Emergency Response Program work, compare 3 kinds of schools randomly selected Megan, Nadia, Julia, Andrea: Quasi-experimental Megan, Nadia, Julia, Andrea: Quasi-experimental Adjustment of golfers to loss of parent vs. loss of spouse Adjustment of golfers to loss of parent vs. loss of spouse Practice time, play, scores, Practice time, play, scores, Xian, Marielle, Kara, Susan: Observational Xian, Marielle, Kara, Susan: Observational Dawson College: Trauma of the school shooting will demotivate students Dawson College: Trauma of the school shooting will demotivate students Emily, Beth, Hollie: Correlational Emily, Beth, Hollie: Correlational Personality type and reading you horoscope (e.g., suggestability) Personality type and reading you horoscope (e.g., suggestability)