Day 2: Research Methods• Essentail Learnings: Be able to describe the pros and cons of

experimental research. • Be able to define and identify independent variable,

dependent variable, experimental group, control group, and extraneous variables.

• Be able to design experimental research.

PSYCHOLOGICAL RESEARCH

Observation Methods

Experimental ResearchExperimental Research

There are 5 major methods used to collect data in psychological

research:

Case StudiesCase Studies

SurveysSurveys

Correlational ResearchCorrelational Research

Naturalistic ObservationsNaturalistic

Observations

Observation MethodsExperimental ResearchExperimental Research

Involve the direct manipulation of one factor to better determine its effect

Advantages• allows cause-effect

conclusions• control of extraneous variablesDisadvantages

• artificial situations may not generalize

• costly

Observation Methods

Independent Variable: Variable the experimenter is manipulating (has control over)

Dependent Variable: Variable the experimenter is measuring (no control over)

Example: Caffeine improves memory.

Experimental ResearchExperimental Research

A researcher wanted to study the effects of sleep deprivation on physical coordination.  The researcher selected 25 year-old male college students and deprived some of the subjects to either 24, 36, or 45 hours of sleep.

Independent Variable?

Dependent Variable?

EXAMPLE

EXAMPLE• Duco wants to examine whether a new drug increases the memory

of rats. Duco teaches two groups of older rats to find a piece of tasty rat chow in the maze. One group of rats is given the new drug while they are learning the maze. The second group is not given the drug. One week after having learned the maze she retests the rats and records how long it takes them to find the rat chow.

• Independent Variable?

• Dependent Variable?

Experimental ResearchExperimental Research• Control Group:

• Untreated or unexposed to some procedure (not manipulated) • Serves as the baseline to compare results to – compared with

treated subjects in order to validate the results

• Experimental Group: • contains the treated subjects in the experiment (manipulated)

• Example: Caffeine increases memory

Placebo Effect • Given in the control group – to better conclude cause and

effect relationship

• Caffeine and memory: • One group given a caffeine free mountain dew

Experimental ResearchExperimental Research• Extraneous Variables:

• any other factor that might affect the dependent variable that the experimenter did not account for.

• Example: Caffeine impacts memory?• Previous caffeine use, mood, intelligence, memory test difficulty

EXAMPLE • I believe orbitz gum helps people quit smoking

What two groups would I form for my experiment?

Independent Variable? Dependent? Extraneous?

EXAMPLE • A researcher wanted to assess whether mood influenced people's

memory. The researcher hypothesized that positive moods would lead to greater memory performance than would a negative mood state. On Monday the researcher had 50 subjects learn a random words and then watch a very humorous comedy film. Their recall of the list of words was then assessed. On Tuesday the researcher had a second group of 50 subjects learn the same list of words and then watch an upsetting documentary on World War II. Their recall of the list was then assessed after having watched the film.

• Extraneous Variables?

EXAMPLE

• A researcher wanted to see whether a new way of teaching English was superior to a more traditional approach. The researcher selected two Thursday night classes at a local community college. In one class the instructor used a traditional method, the second instructor used the newer approach. The researcher then assessed students language ability after they had completed the program.

• Extraneous Variable?

Operational Definition • Defines ambiguous terms, specific explanation/definition of

independent and dependent variable

• Example Caffeine impacts memory? • 1 can of mountain dew and a memory task of having 2 minutes to

memorize 20 three digit numbers.

• Hypothesis: Watching violent television increases violent behavior for elementary aged students.

Note

*Hypothesis always in an “IF” “THEN” form

If you drink caffeine then your memory performance will improve

If you get 9.25 hours of sleep a night or more then you will perform better academically

If you workout three times a week or more then you will lose 10 lbs in one month

Sentence Activity Simpson practice worksheet

Create your own experiment

• New Day

Population & Sample

• population: The larger group that the results of research should apply to

• Sample: people that participate in the research • The sample MUST reflect the larger population!

Example

• Research Question: Drug use among adolescents in the United States.

• Research Method: Distribute a survey to Ms. Duco’s two Psychology classes containing 61 students

• Population: • Adolescents in the United States

• Sample: • 61 Psychology students in BHS

Random Sample• Everyone in your population has an equal

chance at being selected

• Sample should be random!• Best representation• Low bias

• Both on your part and/or your subject’s part!

• Did the previous research mentioned use a random sample? • Not a representation of all adolescents in the U.S.

• How can you ensure random sampling?

Why the 1936 Literary Digest Poll Failed

• Alf Landon and Franklin Roosevelt • 10,000,000 surveys (largest ever) were distributed by Literary

Digest. • the individuals surveyed were selected from automobile owners,

telephone subscribers, and country club memberships.• On the basis of 2,300,000 responses Literary Digest predicted

that Republican Alf Landon would defeat Democratic candidate Franklin Roosevelt by a landslide by election standards.

• Why was the prediction so wrong? • The voters used in the sample were not representative of the

general voting population. In 1936, telephones and automobiles were unaffordable to the average voter

• Moral: Need a representative sample!

Random Assignment • Randomly assigning participants to the experimental and

control group

Double-blind procedure • Neither the participants nor the researcher knows which

group received the placebo

Ethical experimentation on people1. Informed consent

2. Protect them from harm

3. Confidential

4. Debrief

•Create your own experiment • Remember it must be able to be conducted in a

laboratory • Unlimited funding and supplies

Observation MethodsSurveysSurveys

Involve asking people questions about their beliefs and behaviors

Advantages• allows study of difficult-to-observe behaviors, thoughts

and feelings• easy to distribute to large

groupsDisadvantages• people who respond may not be

representative (volunteer bias)• responses may be biased or untruthful

• How much do you know about the American population? • High low game

Observation MethodsNaturalistic

ObservationsNaturalistic

ObservationsInvolve observing behavior as it unfolds in a natural settingAdvantages

• behaviors are spontaneous/natural

• inexpensive

Disadvantages• observer bias & selective attention

• time consuming• Hawthorne effect

Naturalistic Observation

85 percent of men and women observed at public places in Atlanta, Chicago, New York and San Francisco washed their hands after using a public bathroom. In the telephone survey, 96 percent of people said they always washed their hands after using a public bathroom 98% of women observed washed their hands 67% of men observed washed their hands

Observation MethodsCase StudiesCase Studies

Involve intensive examination of a single person or group

Advantages• deep understanding of subject• allows studies of rare behaviors

Disadvantages• difficult to generalize—conclusions may only apply to that particular person or group

Ways to Observe Change Over Time

Longitudinal(p. 309)

Longitudinal(p. 309)

Observe one group of participants over an extended period of time

Advantages• enables researchers to see

how individuals change over time

Disadvantages• time-consuming & expensive• risk of drop-outs

Ways to Observe Change Over Time

Cross-Sectional(p. 309)

Cross-Sectional(p. 309)

Compares people in different age groups all at one time

Advantages• less time-consuming

Disadvantages• differences may not be due to age or development, but due to other factors such as era

• With table partner design research ideas:

• Naturalistic Observation: • Upperclassmen eat healthier than underclassmen. Observe the

cafeteria for three days and record what students eat. • Survey topic for adults:

• Political beliefs of adults. Pass out of survey asking students if they are republican, democrat, not political, or other. Ask how many are planning to vote. Ask how active they are in following politics

• Case study: • Study of terminal cancer patient, how they are coping with their

disease.

All Methods Work to Help Determine…

Correlation the extent to which two or more variables are associated with one another.

If two variables are highly correlated, it means that in the presence of one variable, there is a high likelihood that theother variable will also be present.

Correlation = Causation?

So…If two variables are highly correlated can we determine a cause-

and-effect relationship between them?

Variable A: poor attendance

Variable B: poor grades

Correlation

Variable A could cause variable B.

Poor attendance could cause people to miss tests and homework, and so they end up getting bad grades.

Correlation

Variable B could cause variable A.

The frustrations of poor grades might cause people to decide not to go to school.

CorrelationOr a third variable could cause A and B.

A person might have a full-time job that causes them to miss school and not do their homework.

Correlation vs. Causation

Violence

&

Ice Cream Sales

Or is there a 3rd Variable?

Correlation vs. Causation• It’s important to remember that correlation does NOT equal

causation!• Always question the initial conclusion research might lead you to

believe!“Floss more, live longer”

“Lack of church attendance common denominator in families with ADHD kids.”

People who eat frosted flakes for breakfast are less likely to get cancer than those who eat oatmeal for breakfast.

Correlation Causation

The only way to determine a cause-and-effect relationship is to carry out a laboratory experiment!

The variables are controlled in these experiments, reduce extraneous variables.

Analyzing Correlations• Positive Correlation = Direct relationship

• As one goes up the other goes up • +.6 correlation between drug use and jail time

• Negative Correlation = Inverse relationship • As one goes up the other goes down• -.7 correlation between drug use and years in education

• Range: • -1 to +1 • The closer to one the stronger the correlation • What is stronger -.7 or +.6?

• No correlation: 0 • Perfect correlation: 1 (very rare)

Happiness and helpfulness:as people’s happiness level increases, so does their

helpfulness

GPA and hours of T.V. watched a week

Income and Years of Education

Positive or Negative?

•Class correlational survey results

•Complete Correlation Practice Worksheet

Design survey to implement