1. Psychology as a Science
In this discussion we will explore:
limits of common sense
science - a method for understanding
methods of science
description
correlation
experimentation
evaluating data with statistics
sources of error and bias in research

2. Can we trust our intuition?
How do we know things?
‘We Just Know It’ – Intuition or Common Sense OR
Tried and True Science
Can we trust our intuition?
(Activity - add)

3. Science vs. Common Sense
Why don’t we rely on intuition (common sense)?
(Activity – Research/1st Brain Games clip 0-8:18)
1. Hindsight Bias – tendency to believe, after learning an outcome, that one would have foreseen it.
To find out something has happened, makes it inevitable – I Knew It All Along Phenomenon
(Activity-%)

4. Why don’t we rely on intuition (common sense)?
2. Overconfidence – we tend to think we know more than we do
Humans are usually more confident than correct.
Try these anagrams: WREAT
ETRYN
GRABE
OCHSA

5. Why don’t we rely on intuition (common sense)?
Water
Entry
Barge
Chaos
Once people know the target word, hindsight makes the words obvious. We believe that we should have seen the solution in a shorter period of time.
(2nd Brain Games

6. Science vs. Common Sense
Common sense and intuition often tell us about psychology
e.g., suppose a study tells us that ‘separation weakens romantic attraction’
common sense may tell us - “out of sight, out of mind”
or common sense may say the opposite - “absence makes the heart grow fonder”
Common sense can be inconsistent and based on hindsight

7. Science vs. Common Sense
Science helps build explanations that are consistent and predictive rather than conflicting and postdictive (hindsight)
Science is based on
knowledge of facts
developing theories
testing hypotheses
public and repeatable procedures

8. Scientific Inquiry/Research
Facts are what need to be explained
objective - viewable by others
based on direct observation
reasonable observers agree are true
Theory is a set of ideas that
organizes facts
makes predictions about observations (new facts)
Hypothesis
prediction about new facts (often implied by theory)
can be verified or falsified

9. Scientific Inquiry/Research
As a check on their bias, psychologists report their findings with –
Operational Definitions (of Concepts):
a statement of the procedures used to define research variables
Operational Definitions allow others to replicate the study (repeating the essence of the study to get similar results).

10. Research Methods in Psychology
Setting - field vs. laboratory
Methods of data collection
self-report vs. observational
Research plan or design
descriptive
correlational
experimental

11. Descriptive Research Describes a set of facts
Does not look for relationships between facts
Does not predict what may influence the facts
May or may not include numerical data
Example: measure the % of new students from out-of-state each year since 1980

12. Descriptive Research Types of descriptive research Case Study
In-depth study of one individual
Naturalistic Observation
Recorded observation of people or animals in their natural environment – focus on a specific behavior
Survey

13. Surveys
Wording Effect - need to watch for bias, order of wording, too general
(attractiveness, intelligence)
Sampling
False Consensus Effect – tendency to overestimate other’s agreement with us
Creates the need for a representative sample of the population

14. Surveys Sampling Cont’d.
Population – all the cases in a group, from which samples may be drawn for a study (e.g. study on studying habits – population would be all students)
Random Sample – sample in which every person in a group has equal chance of participating

15. Descriptive Research
Pros vs. Cons

16. Correlational Resarch
Collects a set of facts organized into two or more categories
measure parents disciplinary style
measure children’s behavior
Examines the relationships between 2 or more categories
e.g., more democratic parents have children who behave better

17. Correlational Research
Correlation CANNOT prove causation
Do democratic parents produce better behaved children?
Do better behaved children encourage parents to be democratic?
May be an unmeasured common factor
e.g., good neighborhoods produce democratic adults and well behaved children

18. Correlational Research
Scatterplots – graphed cluster of dots, each of which represents the values of two variables
See pg. 27 for examples
Correlation Coefficient – a statistical measure of relationship
Statistical measure of the extent to which two factors vary together, and thus of how well either factor predicts the other.

19. Correlational Research

20. Direction of a Correlation
(slope of the points)
Positive Correlation – as one variable goes up, the other variable tends to go up (so as one goes down, the other goes down) – max
Negative Correlation – as one variable goes up, the other tends to go down, the inverse is also true – min
No Correlation – correlation is 0.0

21. Strength of Correlation
(amount of scatter)
The higher the correlation coefficient is (without regard to sign) the stronger the correlation is.
The stronger the correlation is, the better one variable can predict the other.

22. Correlational Research
Correlations make visible relationships that we might otherwise miss.
They also restrain our “seeing” relationships that actually do not exist – illusory correlations – perception of a relationship where none exists
(e.g., superstitious beliefs)
Believe – likely to notice and recall

23. Perceiving Order
As humans we want to make sense of our world, so we look for meaningful patterns.
Prob – Random sequences often don’t look random – leads to illusory corr.
If someone flipped a coin six times, which of the following sequences of H and T would be most likely?
HHHTTT HTTHTH HHHHHH

24. Correlational Research
A little note about correlation –
CORRELATION
DOES NOT PROVE CAUSATION!!

25. Experiments
Direct way to test a hypothesis about a cause-effect relationship between variables
One variable is controlled by the experimenter
e.g., democratic vs. authoritarian classroom
The other is observed and measured
e.g., cooperative behavior among students

26. Experimental Variables
Independent variable
the controlled factor in an experiment – what the experimenter manipulates
hypothesized to cause an effect on another variable
Dependent variable
the measured facts/data
hypothesized to be affected

27. Independent Variable Must have at least two levels
categories - male vs. female
numeric - ages 10, 12, 14
Simplest is experimental vs. control
experimental condition gets treatment
(e.g., gets the new drug)
control condition does not
(e.g., gets the placebo)
(created when using a double-blind procedure)

28. Experimental Design Levels may differ between or within people
Within-subject experiment - different levels of the independent variable are applied to the same subject
Between-groups experiment - different levels of the independent variable are applied to different groups of subjects

29. (e.g., placebo takes a study skills seminar, non random assignment)
Sources of Bias
Confounding Variables -
Any variable besides the independent variable that affects the dependent variable in one group but not the other.
(e.g., placebo takes a study skills seminar, non random assignment)

30. Experimental Design
Random sample - every member of the population being studied should have an equal chance of being selected for the study
Random assignment - every subject in the study should have an equal chance of being placed in either the experimental or control group
Randomization helps avoid false results

31. Experimental Design
Validity – extent to which a test measures or predicts what it is supposed to
Internal Validity – controlled for confounding variables (if random assignment is violated, can destroy internal validity)
External Validity – generalizability (if random sample is violated, can destroy external validity)

32. Sources of Bias Observer-expectancy effect Subject-expectancy effect
researcher has expectations that influence measurements
Subject-expectancy effect
subject knows design and tries to produce expected result
Blinding
minimize expectancy by removing knowledge about experimental conditions

33. Blinding
Single-blind study - when subjects are kept uninformed as to the treatment they are receiving
Double-blind study - when both subjects and experimenter are kept uninformed about aspects of the study that could lead to differential expectations

34. Double Blind Procedures
Double Blind Procedures allow researchers to check for a treatment’s actual effects apart from the placebo effect –
- experimental results caused by expectations alone; such as a research participants’ enthusiasm for it or the healing power of belief

35. Research Settings Laboratory Field research
a setting designed for research
provide uniform conditions for all subjects
permits elimination of irrelevant factors
may seem artificial
Field research
behavior observed in real-world setting
poor control over conditions
measures may be more representative of reality

36. Data-Collection Methods
Self-report - procedures in which people rate or describe their own behavior or mental state
questionnaires
rating scales
on a scale from 1 to 7 rate your opinion of …
judgements about perceptions
on a scale from 1 to 100 how hot is ...

37. Data-Collection Methods
Observational methods - researchers directly observe and record behavior rather than relying on subject descriptions
naturalistic observation - researcher records behavior as it occurs naturally
tests - researcher presents stimuli or problems and records responses

38. Data-Collection Methods
Cross-Sectional Studies –study in which subjects of different ages are compared at a given time
Longitudinal Studies – study in which subjects are followed and periodically reassessed over a period of time

39. Data-Collection Methods
Meta-Analysis – combine and analyze data from many studies; it determines how much of the variance in scores across all studies can be explained by a particular variable