1. Chapter 2: Thinking Critically, Scientific Method, Research Methods
Psychology as a Science
Chapter 2: Thinking Critically, Scientific Method, Research Methods 1

2. Overconfidence Effect
“We don’t like their sound. Groups of guitars are on their way out.” Decca Records, in turning down a recording contract with the Beatles in 1962.
Brain Games Overconfidence
Trouble with Overconfidence

3. Perceiving order in Random events.
When shown they aren't accurate, participants explain away the results. Perceiving order in random events. Random sequences often don't look random. Ex. faces on moon or jesus toast.

4. Critical Thinking
Critical thinking does not accept arguments and conclusions blindly.
It examines assumptions, discerns hidden values, evaluates evidence and assesses conclusions. Th
The Amazing Randi
What is he known for in the field of psychology?

5. Thinking Critically… Be All You Can Be! Curious Skeptical Humble
explore to understand
Skeptical
ask why and how – don’t assume
look for evidence
Humble
not all theories workout – test and retest new (and surprising) theories and ideas

6. Goals of Psychology
Goal:
Description of Goal

7. Theories, Hypotheses, Tests, Results
Scientific Method
Theories, Hypotheses, Tests, Results

8. Scientific Method Basic Procedures:
Develop a hypothesis (prediction based on an educated guess – must be testable!)
Perform a controlled test (operational definition – how will it be measured?)
Gather objective data
Analyze results (accept or reject hypothesis)
Publish and replicate results (a well supported hypothesis can be replicated many times with the same results)

9. Scientific Method EXAMPLE:
Theory – “Marijuana use has negative effects on the brain and central nervous system”
Hypothesis – “Marijuana use affects short- term memory”
Controlled Test – sampling of users/non-users and a series of memory exercises/tests

10. Descriptive, Correlational, Experimental
Research Methods
Descriptive, Correlational, Experimental
Psychology’s Goal #3:
Predict behavior

11. Why do we need research? Psychology is a science Overconfidence
it must be based on research (empirical evidence)
Overconfidence
we think we know more than we do
Common sense and intuition are often incorrect and provide no supporting evidence
Hindsight bias
false consensus effect
illusory correlations 11

12. Terms to know: hindsight bias applied research basic research theory
hypothesis
dependent variable (DV)
independent variable(IV)
operational definitions
confounding variables
random sampling
false consensus effect
correlation coefficient
scatterplots
illusory correlation
double-blind effect
placebo effect

13. Case Study, Survey, Naturalistic Observation
Descriptive Research
Case Study, Survey, Naturalistic Observation

14. Descriptive Research Any research that observes and records
Does NOT explain behavior, it only describes
Describe what you see happening in this picture

15. Descriptive Research PROS CONS
The subject remains in a natural, unchanged environment
Used as an overview prior to scientific experiments as to what is reliable or testable
Relatively low cost
CONS
No statistics - can’t analyze results
Results cannot always be replicated
Often seen as unreliable and “unscientific”

16. What could be the strengths and weaknesses of a case study?
One person or situation is observed in depth
Phineas Gage
VA Tech
What could be the strengths and weaknesses of a case study?

17. 1. Case Study PROS CONS full, detailed picture
provides a basis for future experimental study
CONS
some subjects are atypical
cannot always make general conclusions for a larger population

18. How could we obtain a random sample of WBHS students for a survey?
Used in both Description and Correlational research
Interview via mail, phone, internet, etc.
Random Sampling can increase the likelihood that the answers reflect the general population
How could we obtain a random sample of WBHS students for a survey?

19. 2. Survey PROS CONS greater access to diverse populations
easy to get random samples (provide more generalized conclusions for population)
anonymous
cheap
CONS
lacks depth
low response rate
people can lie or misrepresent themselves
wording can affect answers provided

20. 2. Survey By a show of hands…
How many approve government censorship of the media’s portrayal of sex and violence?
How many are in favor of more restrictions on what is shown on TV?

21. 2. Survey

22. 3. Naturalistic Observation
Observing and recording behavior in a natural environment
Observer controls nothing

23. 3. Naturalistic Observation
PROS
View subject in natural environment
Unobtrusive
Leads to correlational research to understand cause/effect
CONS
Observations can be skewed if subject is aware
Only describes, does not explain why

24. Correlational Research
Correlation and Causation, Illusory Correlations

25. Correlational Research
Detects relationships between two variables
Measured using a correlation coefficient
= a statistical measure of relationship (scores range from +1.0 to -1.0)
Graphed using a scatterplot
DOES NOT PROVIDE CAUSE-EFFECT EXPLANATION!

26. EXAMPLE: Is there a correlation between watching TV and low grades in school?

27. Reading a Correlation Coefficient:

28. Scatterplots

29. Is there a correlation between watching TV and lower grades in school?
Reading a Scatterplot
Is there a correlation between watching TV and lower grades in school?
This is a negative correlation - as more hours are spent watching TV, grades in school decrease

30. What information can we gather from this scatterplot?
Reading a Scatterplot
What information can we gather from this scatterplot?
This is a negative correlation - as the weight of the car goes up, the mileage per gallon goes down

31. EXAMPLE: Is there a correlation between a person’s level of income and years of education?
Participant
Income
Years of Education #1
125,000 19 #2
100,000 20 #3
40,000 16 #4
35,000 #5
41,000 18 #6
29,000 12 #7 14 #8
24,000 #9
50,000
#10
60,000 17

32. CORRELATION DOES NOT PROVE CAUSATION!!!
How is this possible?
There is a positive correlation between ice cream sales and murder rates.
CORRELATION DOES NOT PROVE CAUSATION!!!

33. Illusory Correlations
Perception of a relationship where none exists
EX: Large dogs are more aggressive and have more instances of biting people than small dogs.
If you believe there is a relationship, then you will begin to notice and recall events that support your belief (“self-serving bias”)

34. Correlational Research
PROS
Shows relationships between behaviors
Statistically shows how strongly behaviors are related
CONS
Does not identify the cause, only reports relationships
Cannot “prove” anything, only predicts possible behavior

35. Experimental Research
Blind, Double-Blind

36. Experimental Research
Demonstrates cause-effect relationships
Blind Experiments
Double-Blind Experiments

37. Steps in Designing an Experiment:
Hypothesis
Random Selection of population
Identification of independent variable (manipulated) and dependent variable (measured)
Operational definitions for the variables (control confounding variables)
Random Assignment of population into experimental group (exposed to IV) or control group (not exposed to IV; might be exposed to placebo)
Use of blind or double blind procedures
Gathering of data
Analysis of results
Replication

39. Now, Let’s Practice: Hypothesis:
Students who eat an oatmeal raisin cookie before class each day will have higher average scores on the semester final than students who don’t eat a cookie.

40. Confounding variables? Operational definitions Random assignment?
Eating cookies before class each day will lead to higher average scores.
YOUR GROUP MUST IDENTIFY/EXPLAIN:
Random sample?
IV? DV?
Confounding variables?
Operational definitions
Random assignment?
Control group? Placebo?
Experimental group?
Blind? Double blind?
Gather data?
Analysis. Generalizable? 40

41. Experimental Research
PROS
Demonstrates cause- effect relationships
Empirical Evidence to support hypotheses/ theories
CONS
Not always feasible to perform experiments
Not ethical to manipulate certain variables

42. Experiments Using Animals:
Three advantages to using animals -
Behavior of animals can be controlled in a manner not possible with humans (cages, etc.)
Short life spans
(Can study several generations )
Some experiments can be performed on animals but not on humans
(EX: UPenn baboon experiments to study effects of whiplash on the brain; drug therapy)

43. Ethical Guidelines for Human Experiments:
1. Informed consent
2. Protection from harm
3. Right to withdraw
4. Confidentiality
5. Debriefing