Transcript File

Psychology
The Study of Human Behavior
Purpose of Psychology
-To describe behavior
- To predict behavior
- To change behavior
Common sense says…
Opposites Attract
Birds of a Feather
Stick Together
Out of Sight
Out of Mind
Absence Makes the
Heart Grow Fonder
Ways to Study Behavior
Observe
Naturalistic
Ask
survey
Test
Experimental method
Case study
longitudinal
Cross section
How to universalize
Who does it apply to….
Population
(Stratified)
Sample
Random selection
assignment
Cause - Effect
Operational Definition; to operationalize
Independent Variable
Dependent Variable
Controlled Variables
Between Group Design vs. With-in Group Design
Operationalize
Billy is on a new behavior program, will it make him act more friendly
toward others
1 People dream more If they have eaten a big meal 3 hours before sleep
2 How do different types of jokes affect a person’s sense of humor.
3 Overall senior girls are prettier than junior girls but the juniors are less
insane
4 People who make over $300,000 a year tend to be snobs
5 School spirit is at an all time low
6 The Rolling Stones are the best rock group ever.
7 College athletes are not as smart as regular students
8 A psychologist wants to know if counseling will make people less
depressed
Hypothesis
Utilize the following format
If-----(IV)
Then -----(DV)
Errors
Every (experiment)
Study (Subject Selection)
Can (Control/Confounding)
Be
(Bias)
Pretty (Practice Effect)
Dirty (Demand Effect)
Experiment Design
Most general of the errors. There are
many, many ways to botch the
design of an experiment.
Subject Selection
Selection must be random
Assignment must be random
If subject reflect the population
Confounding Variables
Other variables
-that could cause the behavior
-stuff not accounted for
Control Errors
Things not kept the same for all
subjects
Bias
Experimenter Bias
Researcher influences results
E.g.
– The experimenter mood,
– facial expression
– actions
Practice Effect
Your subjects get better as they do it
longer.
E.g.
- Most tests of manual dexterity
– Color discrimination
Demand Effect
Subjects intentionally do act the way
the experimenter expects them to.
Examples:
– The good subject – The subject tries to “help”
the experimenter by doing whatever it takes to
confirm the hypothesis
– The negative subject – The subject tries to
destroy the credibility of the study.
Ethics
Consent
Protection
Confidentiality
Debriefing
Animal Studies
Types of Statistics in
Psychology
Descriptive Statistics: Describe data
to get meaning
Inferential Statistics: Use data for
drawing conclusions
Descriptive Statistics
Central Tendency
Measures of Variability
Standard Scores
Bell Curve
Measures of Central Tendency
A number describing a typical score
around which the other scores fall
Mean = average
Median= score that in the middle;
half the values fall and half below
Mode = most frequently occurring
score
Measures of Variability
Provide a single number that tell us
how spread out the scores are
Range = Difference between the
highest and lowest scores
Standard Deviation = how much a
typical score differs from the mean of
a group of scores
Z Score: how many standard
deviations above or below the mean
Bell Curve
Normal Curve: Bell-shaped curve,
most scores in the middle and very
few extremely high and low scores
Mean, Median & Mode all equal
When it isn’t – skewed right or left
Fig. A.3 The normal curve. The normal curve is an idealized mathematical model. However, many
measurements in psychology closely approximate a normal curve. The scales you see here show the
relationship of standard deviations, z-scores, and other measures to the curve.
Fig. A.4 Relationship between the standard deviation and the normal curve.
Inferential Statistics
Statistical Significance: Degree to which
an event is unlikely to have occurred by
chance alone
p<_ .05
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Correlation
Shows a relationship between 2
variables
Corelation Co-efficient between
-1 and 1 (slope)
Bell Curve
Study Chart
Correlation
Professor Perry is interested in testing
whether the amount of time a person
spends with children affects his attitudes
toward having children of his/her own. She
randomly chooses a sample and randomly
assigns them to two groups. Group 1 spends
5 hours a day for a week with a group of
children. Group 2 spends 1 hour a day for a
week with the same group of children. At
the end of the week, Professor Perry
measures their attitudes with a survey.