AP Psychology by Pbl5Hxt


									      AP Psychology

            Ms. Simon
     September 17-24, 2009
Introduction to Research Methods
         Hindsight Bias

The tendency to believe, after learning
an outcome, that one would have
foreseen it
           Scientific Theories
• Set of principles that organize and predict
  behaviors or events

• Link observed facts

• Imply hypotheses that offer testable
       Subfields of Psychology
• Basic Psychology- research

• Applied Psychology- research put into practice
  as therapist

• Psychiatry- a medical field- deals with mental
  disorders- prescribe medication
There are three main types of
research methods in


       Descriptive Study:
1) Case Study- psychologists study one
   individual in great depth in hopes of
   revealing universal principles
            Case Study Pros
• Detailed information

• Unusual Cases

• Inexpensive

• Few ethical considerations
The Problem with the Case Study:

An individual may be atypical

Cannot generalize results

Difficult to Manipulate Variables

Difficult to quantify data
      Naturalistic Observation
• Observe subjects in natural habitats
  without interacting
     Naturalistic Observation

Pros            Cons
Realistic       No manipulat-
Inexpensive     Ion of
Few ethical     Observer Bias
           Survey Method
• Relies on questions answered by a
  group of people in interviews or
          Survey Method
• Experimenter must identify the
  population to study

• Random sampling picking members
  from a population randomly to
  ensure a representative sample
         Survey Method

Pros              Cons
Can gather lots   Honest
of data           answers?
Few ethical       Need many
considerations    participants
Inexpensive       Wording Effects
           Wording Effects
• In a study by AMNH, 88% of all
  respondents said that they were
  interested in plants and trees, but only
  39% said they were interested in botany.

• One out of five Americans (22 percent)
  doubted that the Holocaust had
  occurred. 12% said they weren’t sure
           What to Watch for…
• Order of choices

• Is the time frame specified?

• How personal or direct is the wording?

• Is there a cultural bias?
        Correlational Studies
• Correlational studies assess the
  association between two or more
  characteristics of interest without
  ascribing causes

• Is a correlational study an experiment?
  Correlation coefficient

Example: R= + .37
Correlational Studies
    Correlational Studies
Pros           Cons
Inexpensive    Confounding
Few ethical    Illusory
considerations correlation
Time           Does not
Objective      I mply
           Illusory Correlation
• When we believe there is a relationship
  between two things, we are likely to notice
  and recall instances that confirm our belief
What is the correlation?
• 1) good looks/popularity
• 2) self-esteem/depression
• 3) brain size/intelligence
• 4) money/happiness
• 5) Education/length of life
 Correlation: determining causation
There is a strong
correlation between
people who ate
oatmeal for
breakfast as a child
and cancer versus
people who ate
Frosted Flakes for
breakfast as a child
    Friday’s Exam: What to Study
• About 40% Historical Approaches, 60%
  Research Methods

• Study mostly from Class Discussion!

• Format: Multiple Choice, One short AP exam
  style essay question, short answer and/or
                    Research Methods
Descriptive          Correlational             Experimental
Explains behavior    assess the                Researcher
using natural        association between       manipulates one
observations         two or more               variable and
                     characteristics of        observes the effect
                     interest                  on another variable

1) Case studies      1) Causation              Experimental Design
2) Naturalistic      2) Illusory correlation   Confounding
3) Surveys           3) Correlational          Variables, double-
                     Coefficient               blind
       Experimental Method
• Researcher manipulates one
  variable (independent variable) and
  observes the effect on another
  variable (dependent variable)

• Allows one to show a causal
• Q: How is the experimental group different
  from the control group?

• A: The experimental group receives or
  reacts to the independent variable and the
  control group does not receive the
  independent variable

• Q: Why is a control group needed?

• A: Provides baseline for comparison
Confounding variable:
 external differences between
the experimental group and the
control group other than those
 resulting from
 the independent
     Confounding Variables

1) Placebo Effect
experimental results caused by
expectations alone
        Confounding Variables
• Demand Characteristics- participants form an
  interpretation of the experiment's purpose
  and unconsciously change their behavior
 How can we control for
confounding variables?
   How can we control for
confounding variables?
       1) Random Assignment
method of assigning subjects to groups to
minimize pre-existing differences between
those groups
 This is an example of Between subjects
design: Participants in the experimental and
control group are different individuals
How can be control for
 confounding variables?
 2) Within subjects design
 Technique where subjects serve as control and
 experimental group.

  3) Twin Studies:
      Confounding Variables
• Experimenter bias- researcher’s
 expectations about the outcome of
 a study influence the results

Q: How can we eliminate
 experimenter bias?
How can we eliminate experimenter bias?
 1. Multiple Experimenters

 2. Double blind procedure-
    research design in which neither
    the experimenter or the
    participants know who is in the
    experimental versus control
 AP Psychology

      Ms. Simon
 September 24, 2009
Experimental Statistics
            Do Now:

• From your reading: Why do we
  need operational definitions?
How do psychologists present data?
• Frequency Distributions
• Statistical significance (p) is the
  likelihood that the observed
  difference between groups
  results from a real difference
  rather than chance alone

• What’s a good p value?
When is data statistically significant?
       ) Large difference between the two means

1) Large difference between
       the two means
When is data statistically significant?
 When is data statistically significant?

2) Small standard deviations
But… what’s a standard deviation?
A standard deviation is the degree by
 which a score varies from the mean

You don’t need to know the equation!
When is data statistically significant?
 When is data statistically significant?

3) Large Sample Size
   Mean, Median, Mode

6, 7, 8, 9, 10, 10, 10, 11, 11, 11,
 11, 12, 12, 13
What’s the mode?

What’s the median?
Normal Distribution
Skewed Data
• Activity: design an experiment to see if
  aggression is related to violent TV watching

  Be sure to address random selection, random
  assignment, experimental versus control
  group, confounding variables, and how you
  will minimize the effects of experimental and
  observer bias.

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