Unit 2 Experimentation

Or How do psychologists get all that data to support their theories???

Psychological studies…

Provide broad scientific information

Explain what we doTell us why we do it and tell us what changes

occur over time!!!

Accurate experiments…

Give us solid information

Allow psychologists to support theories about behavior

Psychologists get data using…

SurveysCase StudiesNaturalistic observation InterviewsCross-sectional studiesLongitudinal studies

Most methods use…

Sample groups (def.-group that represents a

larger group) WHY??? Because its too

expensive and takes too much time to get data from everyone in the whole wide world (even with the internet!!!)

Why do psychologists need so many methods??

Because some work better than other in different situations

Interview– face to face questions Survey- answer questions

usually anonymously Advantage/disadvantage of

each???

All psychologists use …

The Scientific Method!!!

Which is defined as the procedure to gather and interpret data

BUT… EXPERIMENTATION

Is the most used method by psychologists to gather data

Experiments are a causal relationship between two variables or stated this way…

IF X , THEN Y

TWO types of experiments are…

Laboratory – done in a lab (DUH!!!)

Field – conducted out in the real world

What are the advantages and disadvantages of each????

Elements of experiments:

Hypothesis- an educated guess Subjects- people on which the

experiment is conducted Variables- factors in the

experiment (psychologists try to identify and control the variables)

Types of Variables…

Independent variable: has an effect on other variables (is messed with by the psychologist)

Dependent variable: changes in an experiment so it is always measured!!!

Hidden variables– unwanted variables that if not detected can change the results

Many factors influence our behavior. Experiments (1) manipulate factors that interest us, while other factors are kept

under (2) control.

Effects generated by manipulated factors isolate cause and effect relationships.

Exploring Cause & Effect

Placebos…

Has no active ingredients Sometimes called “the sugar

pill” Can also work by the power of

suggestion ( mind over matter) Up to 30% of people on placebos

get better (who’d have thought that!!!)

Subjects are put into groups..

Experimental group- gets the active ingredient (the IV)

Control group- gets the placebo

WHY?? So psychologists can compare the two !!!

Bias can come from…

“Hidden” or confounding variables Participant bias- when the subjects

try to influence the results either deliberately or accidentally

Researcher Bias- when the psychologist influences the results either deliberately or accidentally

Results in “bad” data

How do we know if the results are good?????

Replication!!!!If an experiment can be repeated with the same results… the hypothesis is good.

Correlation

When one trait or behavior accompanies another, we say the two correlate.

Correlation coefficient

Indicates directionof relationship

(positive or negative)

Indicates strengthof relationship(0.00 to 1.00)

r = 0.37+

Correlation Coefficient is a statistical measure of the relationship between two

variables.

or

Correlation and CausationCorrelation does not mean causation!

Illusory Correlation

The perception of a relationship where no relationship actually exists. Parents conceive

children after adoption.

Confirming evidence

Disconfirming evidence

Do notadopt

Disconfirming evidence

Confirming evidence

Adopt

Do not conceiveConceive

Michael N

ewm

an Jr./ Photo Edit

Many factors influence our behavior. Experiments (1) manipulate factors that interest us, while other factors are kept

under (2) control.

Effects generated by manipulated factors isolate cause and effect relationships.

Exploring Cause & Effect

ExperimentationA summary of steps during experimentation.

ComparisonBelow is a comparison of different research

methods.