III. Research MethodsIII. Research Methods

A. How do psychologists A. How do psychologists “do” science?“do” science?

If our intuition, common sense, and folk wisdom is not enough to make valid conclusions about behavior...

Must test our hunches and ideas.– What differentiates psychology from other

disciplines (e.g., philosophy).

A.A. How psychologists “do” scienceHow psychologists “do” science Typical way psychologists approach a problem:

– Make observations, read literature– Come up theory (general explanation).– Develop testable statement (hypothesis) from

theory.

CAN’T STOP THERE!!!– Pick research method, test hypothesis.– Collect data. See if supports hypothesis.

A. How do psychologists “do” science?A. How do psychologists “do” science?

Example:

Children’s aggression & exposure to violent media. 1. Theory:

– An explanation of phenomenon (using an integrated set of principles that organizes or predicts observations).

General claim about behavior.

– Example?

A. How do psychologists “do” science?A. How do psychologists “do” science?

Can’t stop there… 2. Hypothesis:

A testable prediction implied by the theory.

Must be a specific & disconfirmable statement. Example?

B. 4 Goals of PsychologyB. 4 Goals of Psychology

Describe Predict Explain Control/Change

C. Goal #1: C. Goal #1: Describing BehaviorDescribing Behavior

1. 3 Descriptive Research Methods: a. Case Studies:

Study one or a few individuals in depth.

Example: Freud

Limits of method?

C. Goal #1: C. Goal #1: Describing BehaviorDescribing Behavior

1. 3 Descriptive Research Methods: b. Naturalistic Observation:Observe people in their natural environment.

Example: ?Strengths of methodLimits of method: - people may change behavior if know being

observed.

C. Goal #1: C. Goal #1: Describing BehaviorDescribing Behavior

1. 3 Descriptive Research Methods: c. Survey Research:People report behavior, beliefs, or opinions.Examples?Strengths: efficientLimits of method?

- i. honesty of reporting.- ii. biases in survey: wording of questions

Limits of survey method: iii. Sampling: who responded to survey.

Random Sample:

A sample that fairly represents a population because each member has an equal chance of being included in the study.

Aggression and watching violent tv...

If used one of methods above:– What can we conclude?– What haven’t we addressed (can’t we conclude)?:– What should we be aware of when reading about

this research?

C. Goal #1: C. Goal #1: Describing BehaviorDescribing Behavior

2. Statistics used to depict & interpret data: If we collect data, what can we do with it? a. Use graphs to illustrate the data. b. Summarize data by measures of central

tendency.– Mean, median, mode – see text– Is that all?

C. Use measures of variation (dispersion).– Range, standard deviation

D. Goal #2: Predicting BehaviorD. Goal #2: Predicting Behavior

Correlational Research: 1. Involves measuring behaviors or variables that

are already in place.– Could use descriptive methods to get that data. Then...

Apply correlation:

Statistical measurement of the extent to which two variables vary together or are associated/related.

- how much one variable predicts the other.

See overhead:

D. Goal #2: Predicting BehaviorD. Goal #2: Predicting Behavior

Perfect positivecorrelation (+1.00)

No relationship (0.00) Perfect negativecorrelation (-1.00)

D. Goal #2: Predicting BehaviorD. Goal #2: Predicting Behavior Correlation: Value between 1 and –1 2. Two pieces of information correlation

statistic provides:– Direction of the relationship

(sign of correlation: positive or negative)– Strength of relationship

(absolute value of correlation)

D. Goal #2: Predicting BehaviorD. Goal #2: Predicting Behavior

3. Concerns with correlation:– a. “Reverse Causality”

(Cannot determine which variable caused which).

– b. The “third variable” problem

(Something other than two variables that were measured accounts for the relationship).

CANNOT CONCLUDE CAUSALITY

D. Goal #2: Predicting BehaviorD. Goal #2: Predicting Behavior 4. Strengths/Limits Strengths:

– efficient– study things can’t control/manipulate in laboratory– allows for prediction

Limits:– Problems with descriptive methods– No causality

D. Goal #2: Predicting BehaviorD. Goal #2: Predicting Behavior

Aggression and playing violent videogames:

If used correlational research:– What can we conclude?– What haven’t we addressed (can’t conclude)?:– What should we be aware of?

E. Goal #3: Explaining BehaviorE. Goal #3: Explaining Behavior

Experimentation– Creating miniature “drama” or event.– Researcher “manipulates” (“creates”one or

more variables/factors vs. correlational research measures existing variables).

– Controlled setting.

E. Goal #3: Explaining BehaviorE. Goal #3: Explaining Behavior

1. Ingredients of an Experiment:

Independent Variable:Variable that researcher manipulates.

Create an experimental condition.

Control Group:Group in experiment that does not receive treatment,

or what is manipulated.

Serves as comparison group to experimental group.

E. Goal #3: Explaining BehaviorE. Goal #3: Explaining Behavior

Dependent Variable:Behavior that is being measured; what is expected to

change due to independent variable.

Example:independent variables

control group (or other group)

dependent variable

E. Goal #3: Explaining BehaviorE. Goal #3: Explaining Behavior

1. Ingredients, cont’d: Random Assignment:

Assigning subjects to experimental or control groups in an experiment by chance, thereby minimizing pre-existing differences between subjects.

How?

***** vs. Random Sampling….

E. Goal #3: Explaining BehaviorE. Goal #3: Explaining Behavior

2. How do we know the differences between experimental conditions are reliable?– Statistical Significance: The difference in the

variables is NOT due to chance.

3. Limits of experimentation:– a. Artificiality of lab.

Is it generalizable? Do people act differently in lab?

– b. Ethics informed consent debriefing

4. Strengths of experimentation.

E. Goal #3: Explaining BehaviorE. Goal #3: Explaining Behavior

Aggression and watching violent tv:

If used experiment:– What can we conclude?– What should we be aware of?

F. Goal #4: F. Goal #4: Controlling/Changing BehaviorControlling/Changing Behavior

Often involves many steps in process:

>Make observations, develop theory, describe phenomenon. > >

> Attempt to find variables that are related

(correlations) > >

> Use that information to develop experiment. >

> From your findings, conclude what may be useful in changing/controlling behavior – application.

G. Compare/Contrast types of methods...

Are researchers and scientists immune to perceptual biases we’ve discussed?

Conclude:– Psychologists have several goals in mind when

doing research.– Different research methods are used to address

each goal.– Each research methods has its good and bad

points.– Important to be aware of what can/can not

conclude when using each method.