Psychological Research Methods

Psychological Research Methods

Excavating Human Behaviors

Intuition

• We make decisions based off “gut instinct” much of the time

Unfortunately, that “gut instinct” (our intuition) is highlylimited…except with multiple choice questions!

This intuition limits our ability to thinkcritically!

Critical ThinkingWhen we think critically, we do not blindly accept arguments & conclusions!•Examines assumptions•Discerns hidden values•Evaluates evidence

VS

Hindsight Bias

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

Overconfidence• We tend to think we know

more than we do.

“There is no reason for anyone to have a computer in their home.” ~ Ken Olson, President of Digital Equipment Company, 1977

“Heavier-than-air flying machines are impossible.” ~ Lord Kelvin, British mathematician, 1895

“Man will never reach the Moon, regardless of all future scientific advances.” ~ Lee DeForest, inventor, 1957

“We regard the agreement as symbolic of the desire of our two peoples never to go to war with one another again. I believe it is peace for our time.” ~ British Prime Minister Neville Chamberlin, after signing the Munich Agreement with Adolf Hitler in 1938 (Oops)

Psychology is a SCIENCE

RESEARCH METHODS

Remember:

It all starts with a THEORY

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.

Scientific Method

OBSERVE:I observe that when guys take “selfies”,

girls are less interested in them.

THEORIZE (PREDICT):I theorize that the more “selfies” a guy

takes, the less dates he will go on.

Hypothesis

• A tentative theory that has not yet been tested – but can be

• IF __________, THEN __________.

•Have operational definitions.•Be replicable.

The SCIENTIFIC METHOD putting our theories to the

test. 

If a male takes a picture of himself either in the mirror or with his camera facing him (“selfie),

he will go on less dates than a male counterpart who does not take these sorts of pictures.

The key to having a hypothesis is having what scientists call operational definitions. An operational definition clearly identifies how variables will be measured and makes replication possible.

I observe that when guys take “selfies”, girls are less interested in them.

The SCIENTIFIC METHOD putting our theories to the

test. The key to having a hypothesis is having what scientists call operational definitions. An operational definition clearly identifies how variables will be measured and makes replication possible.

I observe that when students sleep in class, their grades drop.

Our methods for researching fall into 3 categories:

TESTING OUR HYPOTHESIS

DESCRIPTIVEsimply describes the event

CORRELATIONAL describes the relationship between variables

and allows one to predict behavior

EXPERIMENTALattempt to actually show a cause/effect

relationship

Descriptive Research

• Any research that observes and records.

• Does not talk about relationships, it just describes.

What is going on in this picture?

We cannot say exactly, but we can describe what we see.

Thus we have…..

Types of Descriptive Research

• The Case Study

• The Survey

• Naturalistic Observation

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?

Naturalistic Observation

• Observing and recording behavior in natural environment.

• No control- just an observer.

What are the benefits and detriments of Naturalistic Observation?

The Survey MethodDescriptive/Correlational

• 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).

Survey Method: The Bad

• Low Response Rate

• People Lie or just misinterpret themselves.

• Wording Effects

How accurate would a survey be about the frequency of diarrhea?

Random Sampling

Components of Survey• Population: all the individuals you are

interested in knowing something abouti.e. the entire student body of Ardrey Kell

• Sample: the individuals you actually question.

i.e. Two homerooms from each grade level, selected at random

• Sampling should always be taken randomly from the population so that it is representative meaning each individual in the population had an equal chance of being selected.

DESCRIPTIVE / CORRELATIONAL RESEARCH

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.

Correlational Research• Detects relationships between variables.

• Does NOT say that one variable causes another.

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

Correlation

does NOT equal Causation

RESEARCH METHODS

Just because there is a relationship between two variables does not mean one caused the other

Correlation does NOT equal

Causation

RESEARCH METHODS

Correlational Studies can help researchers predict behavior.

You and your brother are related (correlation)You did NOT cause your brother (causation)

Think of it this way…

positive correlationindicates a direct relationship (as A , B OR as

A , B )

Ex: The more sit-ups you do, the more fat you will lose.

Ex: The fewer sit-ups you do, the less fat you will lose.

negative correlationindicates an inverse relationship (as A , B )

Ex. The more ice cream you eat, the less fat you will lose.

-1.0 -.5 0 +.5 +1.0

Correlation Coefficients• A number that

measures the strength of a relationship.

• Range is from -1 to +1

• The relationship gets weaker the closer you get to zero.

Illusory CorrelationThe perception of a relationship where none exists

• Does kindergarten lead to crime?

• Are the French really overly rude?

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

Population

SAMPLE

POPULATION

Experimental Group Control Group

AS

SIG

NM

EN

T

• Confounding Variable(s): refers to a “hidden” or uncontrolled aspect of an experiment that can distort the results of an experiment.

Example: Having the experimental group tested in a different room than the control group would be a confounding variable. Why?

Experiments Want to Avoid Confounding (Lurking) Variables

EXPERIMENTAL RESEARCH

Analyze Results

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

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

Statistics

• Recording the results from our studies.

• Must use a common language so we all know what we are talking about.

Descriptive Statistics

• Just describes sets of data.

• You might create a frequency distribution.

• Frequency polygons or histograms.

Normal Distribution• In a normal

distribution, the mean, median and mode are all the same.

Distributions

• Outliers skew distributions.

• If group has one high score, the curve has a positive skew (contains more low scores)

• If a group has a low outlier, the curve has a negative skew (contains more high scores)

A Skewed Distribution

Are the results positively or negatively skewed?

Other measures of variability

• Range: distance from highest to lowest scores.

• Standard Deviation: the variance of scores around the mean.

• The higher the variance or SD, the more spread out the distribution is.

• Do scientists want a big or small SD?

Shaq and Kobe may both score 30 ppg (same mean).But their SDs are very different.

Inferential Statistics

• The purpose is to discover whether the finding can be applied to the larger population from which the sample was collected.

• T-tests, ANOVA or MANOVA

• P-value= .05 for statistical significance.

• 5% likely the results are due to chance.