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Psychological Research Methods

Excavating Human Behaviors

“Illusory” Research

Hindsight Bias

• The tendency to believe, after learning the outcome, that you knew it all along.

Only after Kerry won the Iowa Primary, did people begin to say that Dean was too liberal. What would people say about Kerry if Dean won?

Overconfidence• We tend to think we know

more than we do.

82% of U.S. drivers consider themselves to be in the top 30% of their group in

terms of safety

81% of new business owners felt they had an excellent chance of their

businesses succeeding. When asked about the success of their peers, the answer was only 39%. (Now that's

overconfidence!!!)

Scientific Method

1. Observe some aspect of the universe.

2. Invent a theory that is consistent with what you have observed.

3. Use the theory to make predictions.

4. Test those predictions by experiments or further observations.

5. Modify the theory in the light of your results.

6. Go to step 3.

Hypothesis

• A tentative theory that has not yet been tested.

•Have operational definitions.•Be replicable.

Types of Research

• Descriptive

• Correlational

• Experimental

•Case Study

•Survey

•Naturalistic Observation

Descriptive Research

• Any research that observes and records.

• Does not talk about relationships, it just describes.

The Case Study• Where one person (or situation) is

observed in depth.

What are the strengths and weaknesses of using a tragedy like the Columbine School Shootings as a case study?

The Survey Method

• Used in both descriptional and correlational research.

• Use Interview, mail, phone, internet etc…

• The Good- cheap, anonymous, diverse population, and easy to get random sampling (a sampling that represents your population you want to study).

Naturalistic Observation

• Observing and recording behavior in natural environment.

• No control- just an observer.

What are the benefits and detriments of Naturalistic Observation?

Types of Research

• Descriptive

• Correlational

• Experimental

•Case Study

•Survey

•Naturalistic Observation

Why do we sample?

• One reason is the False Consensus Effect: the tendency to overestimate the extent to which others share our beliefs and behaviors.

Measured using a correlation coefficient.

• A statistical measure of the extent to which two factors relate to one another

Correlation Correlation Coefficient

a statistical measure of the extent to which two factors vary together, and thus how well either factor predicts the other

Correlation coefficient

Indicates directionof relationship

(positive or negative)

Indicates strengthof relationship(0.00 to 1.00)

r = +.37

Correlation

There is a positive correlation between ice cream and murder rates. Does that mean that ice cream causes murder?

Correlation

Scatterplot a graphed cluster of dots, each of which represents

the values of two variables the slope of the points suggests the direction of the

relationship the amount of scatter suggests the strength of the

correlation little scatter indicates high correlation

also called a scattergram or scatter diagram

Correlation

Perfect positivecorrelation (+1.00)

No relationship (0.00) Perfect negativecorrelation (-1.00)

Scatterplots, showing patterns of correlations

CorrelationHeight and Temperament of 20 Men

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10

11121314151617181920

80636179746962757760

64767166737063716870

75666090604242608139

48697257637530578439

SubjectHeight in

Inches Temperament SubjectHeight in

Inches Temperament

Correlation

Scatterplot of Height and Temperament

55 60 65 70 75 80 85

959085807570656055504540353025

Temperamentscores

Height in inches

CorrelationThree Possible Cause-Effect Relationships

(1)Low self-esteem

Depression

(2)Depression

Low self-esteem

Low self-esteem

Depression

(3)Distressing events

or biologicalpredisposition

could cause

could cause

could cause

or

or

and

Correlation DOES NOT equal causation

Hippocrates’ Good News Survey found that people who often ate Frosted Flakes as children had half the cancer rate of those who never ate the cereal.

Conversely, those who often ate oatmeal as children were four times more likely to develop cancer than those who did not. Does this mean that Frosted Flakes prevents cancer while oatmeal causes it?

The GNS revealed that people who had had routine physicals in the previous 3 years were twice as likely to report high blood pressure and cholesterol levels. Do physical exams cause health problems?


Children with high self-esteem also tend to have high academic achievement. Why is this?

They are both linked to intelligence and family social status.


John Paulos: Innumeracy: Mathematical Illiteracy and Its Consequences gives this:

Two variables may be correlated because of their relationship to a third factor.

Positive correlation between milk consumption and incidence of cancer.

In the New Hebrides Islands, body lice were at one time thought to produce good health

Positive correlation between the quality of a state’s day care programs and the reported rated of child abuse.

Experimentation

Experimental Research

• Explores cause and effect relationships.

Eating too many bananas causes Constipation

Steps in Designing an Experiment

1. Hypothesis2. Pick Population: Random Selection then

Random Assignment.3. Operationalize the Variables4. Identify Independent and Dependent

Variables.5. Look for Extraneous Variables6. Type of Experiment: Blind, Double Blind

etc..7. Gather Data8. Analyze Results

Experimental Vocabulary• Independent Variable: factor that is

manipulated• Dependent Variable: factor that is

measured• Extraneous Variables: factors that

effect DV, that are not IV.• Experimental Group: Group exposed

to IV• Control Group: Group not exposed to IV• Placebo: inert substance that is in place

of IV in Control Group

Analyze Results

• Use measures of central tendency (mean, median and mode).

• Use measures of variation (range and standard deviation).

A Skewed Distribution

Are the results positively or negatively skewed?

Some psychological research topics:

• origins of stereotypes

• development of language

• causes of Alzheimer’s disease

• accuracy of eyewitness testimony

• personality & musical preference

• treatment of eating disorders

• causes of romantic love

Sampling Psychology: Examples of Psychological

Research Findings:

• visual perception & optical illusions

• information processing & judgment

• human memory

• self-evaluation

Which center circle is larger?

Here are the same circles again.

Do you see the flashing dots?

The flashing is all in your head.

TO THINK ABOUT OR DISCUSS:

• Does the human visual system behave just like a video camera?

• Could optical illusions ever cause accidents?

• Could optical illusions ever prevent accidents?

A memory test:

1. Please listen carefully to the following list of words.

2. Please DO NOT write the words down. Just listen

carefully.

3. In a little while, I’ll ask you to remember the words.

Now count backwards with me slowly, by threes, from

45 to 3:

45, 42 … 3

1. Write down each word below:

ghost cake blanket sweet rabbit candy

2. Circle only the words you heard on the list.

3. If you VIVIDLY remember hearing a word, circle it

twice.

• sour• candy• sugar• bitter• good• taste• tooth• nice• honey• soda• chocolate

Now examine the list carefully:

TO THINK ABOUT OR DISCUSS : Should this make us worry about eyewitness testimony?

• heart• cake• tart• pie

Now we are going to do a simple activity involving letters of the alphabet.

Based on your gut feelings, quickly write down:

1.Your six FAVORITE letters

2.Your six LEAST FAVORITE letters

Look over each list and circle all of the letters that occur in your own first name. Count the number of circled letters in each list.

Which list included more of theletters from your own first

name??

The preference for the letters in one’sown name is the name letter effect.

TO THINK ABOUT: Would people bemore likely to purchase a product if the

product resembled his or her name?

Should the musician depicted here like M&Ms more than the average person does?

Psychological Science:• addresses important

questions

• can improve people’s lives

• is a lot of fun!

Formal Experiments

• Tests relationship of two or more variables

– Allows conclusions about cause-and-effect

– Quantitative measures of behavior compared in different conditions created by researchers

– Evidence supports or rejects hypothesis

Research Methods In Psychology

Formal Experiments• Elements

– Independent variable – gets manipulated

– Dependent variable – amount of change

– Experimental group – exposed to independent variable or conditions expected to create change

– Control group – presents normal behavior used for comparison

– Random assignment–

– Experimental control


0.02

Nonviolent film

Violent film

0.04

0.06

0.08

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0.12

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0.00

Fig. 2.6

Fig. 2.7

Control group: View nonviolent film

Randomly assign into control and

experimental groups

Full population of interest

Experimental group: exposed to independent variable: view violent film

Formal Experiments• Placebo control

– Placebo effect: provides no active effect– Use in identical conditions for control and

experimental groups

• Blind experiment– Researchers blind to group membership of

participants to rule out experimenter bias

• Strongest experiments – double blind– Researchers and participants kept blind


Describing and Interpreting Data• Descriptive statistics – summarized data for large

groups of participants

– Mean: average

– Median: midpoint in rank-ordered data

– Mode: score appearing most often

– Normal distribution: bell-shaped curve

– Standard deviation: degree to which scores in ordered distribution are spread out


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% G

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Mother’s Age

ModeMean & Median

Describing and Interpreting Data

• Reaching conclusions from data

– Statistical significance

• Size of correlation

• Difference of means are greater than chance

– Two issues for significance

• Larger sample size is better

• Statistical difference does not equal practical significance


Ethical Principles of Research

• Ethics in research with human participants

– Freedom from coercion

– Informed consent

– Limited deception

– Adequate debriefing

– Confidentiality


Ethical Principles of Research

• Ethics of research with nonhuman animals

– Necessity

– Health

– Humane treatment


End

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