Building Critical Thinking with Psychological
Science
!
WARNING
Brain at work
__________
Be curious.
Be skeptical.
Be humble.
Critical Thinking
thoughtful consideration of information encountered
knowledge of the methods of logical inquiry and reasoning
some skill in applying those methods
How psychological science helps us do this...
"The naked intellect is an
extraordinarily inaccurate instrument."
Madeleine L'Engle, novelist
The tendency to believe, after learning
the outcome, that one would have forseen it.
hindsight bias
It's like shooting an arrow...
...and then drawing the target around it.
Overconfidence
"Groups of guitars are on their way out."
 Decca Records, 1962
tendency to think we know more than we do.
Perceiving
Patterns
Bee all that you can bee,
in psycholobee
Scientific Method
A selfcorrecting process for asking questions and making observations.
Theory
explains
organizes observations
predicts behaviors or events
Hypotheses
often implied by theory
testable predictions
Caution: our theories can bias our observations
Research & Observations
use operational definitions
clearly defined research variables
reduce bias
should be repeatable
Howard is obsessed with space
Howard can take any topic and use it to remind you he went to space.
Leonard and Sheldon test and repeat their findings
confirm, reject, or revise
hypotheses
Observation & Description
HowTo
Case Study
close study of an individual, group, or event
discovery of what is true for all of us
misleading, unrepresentative information
Case
Study
Naturalistic
Observation
Survey
observe and describe behavior in the natural environment
Naturalistic Observation
Do we learn the cause of behavior?
What are the benefits?
Survey
looks at many cases
random sample represents population
generalizability
Caution: how and what questions are asked effect results
Finding Correlation
a measure of the extent to which two factors vary together, relationship
Research Study
Independent variable:
number of facebook friends
Dependent variable:
number of hours spent studying
hypothesis?
Finding Correlation
Independent variable:
variable whose value influences another variable (number of facebook friends). In an experiment it is the variable that is manipulated.
Dependent variable:
the outcome factor or variable that may change due to independent variable (number of hours spent studying)
Population:
Louisiana Tech students
Sample?
status
update:
yum
Finding Correlations
What does the scatterplot tell us?
IV & DV are correlated, vary together
negative correlation, as one variable goes up the other goes down
Correlation Coefficient
A number that tells strength & direction of correlation, 1.0, 1.0
strength
: how exactly one variable changes as the other does
direction
: positive or negative correlation
both increase or decrease together = positive
one increases the other decreases = negative
Correlation Coefficient
A number that tells strength & direction of correlation, 1.0, 1.0
Perfect negative correlation
correlation coefficient = 1.0
negative correlation
correlation coefficient = .73
So we found a correlation!
Yay!
What does it mean?
correlation does
not
mean causation!
There is a positive correlation between two variables
ice cream sales
bike theft
How do we explain this?
Finding Causation
Experiment:
manipulate factor(s) to observe the effect on another variable
Random
assignment
Experimental group
Control Group
assignment to
groups by chance
Receives treatment
No Treatment
Does coffee improve student alertness in early morning classes?
Placebo effect:
results caused by expectations alone
doubleblind procedure:
Subjects and research assistants are unaware of who is receiving treatment/placebo
Finding Causation
Independent variable?
Dependent variable?
Caffeine, coffee
Alertness
Are there any other factors that might contribute to student alertness?
Confounding variables:
other factors that might cause an effect on the experiment
Describing Data
Measures of Central Tendency
Mean:
the average
Median:
the middle number, half scored above and half scored below
Mode:
number occurring most
Standard deviation
: measure of the average distance of scores from the mean
Normal
curve
Statistically significant
difference shows that our finding is
not
due to chance or a fluke
Remember these little people?
If the results of this study were
statistically significant
...
We'd know the difference in alertness between students not drinking coffee (control group) and students drinking coffee (experimental group) was not due to chance.
Scientific Method
No blind acceptance of arguments or conclusions
Examine assumptions
Discern hidden values
Evaluate evidence
Assess conclusions
We have a tendency to perceive order in random events
Leads us to overestimate our intuition and assumptions
http://www.angio.net/pi/piquery
Population:
whole group being studied
Random Sample
: represents the population, every member of population has equal chance of being selected
typical
atypical
Misleading Data
Is the Mean misleading? Why?
A bat and ball cost $1.10.
The bat costs one dollar more than the ball.
How much does the ball cost?
If it takes 5 machines 5 minutes to make 5 widgets, how long would it take 100 machines to make 100 widgets?
http://paidpost.nytimes.com/netflix/womeninmatesseparatebutnotequal.html?_r=0#.VQXDOY7F_OV
theory
hypothesis
research
confirm or refine theory
But what's the point, really?
confirmation bias
 we have a tendency to notice instances that confirm our beliefs
illusory correlation

belief that chance events are related
regression toward the mean
 extreme measurements tend to fall back toward the mean
Confirmation bias, illusory correlation, regression toward the mean
Chapter 2: Biology of Mind
How does a neuron communicate?
What are some of the functions of the nervous system?
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Chapter 1 (Myers 11ed)
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