Research in Psychology
Agenda
1. Bell Ringer: The Molly Case? (10)
2. Lecture: Research Methods (20)
3. Handout 1-11 and Discussion. (15)
4. M&M Activity, Sampling BB#2 (20)
5. Finish Case Study from yesterday
Objective

By the end of this lesson you will be able to
identify the research methods of
Psychology.

You will be able to define research terms.
Why
do we need research?
Intuition and Critical Thinking
Human Intuition is highly limited.
 Critically thinking rarely comes easily to us!
– Critical Thinking: thinking that does not
blindly accept arguments and conclusions
»examines assumptions
»discerns hidden values
»evaluates evidence
»An awareness to our own vulnerability

Hindsight bias – “I knew it all along”
phenomenon where after learning an
outcome, one believes s/he could have
predicted that very outcome
 Overconfidence – we think we know
more than we actually know
 This is why we need psychological
science.

Natural Observation - Systematic
study of behavior in a natural setting

Description:
– Careful observation of humans or animals in
real-life situations

Strength:
– provides descriptions of behavior

Weakness:
– DOES NOT explain how or why the behavior
occurs – only describes it
Example: Jane Goodall’s research
was naturalistic observation
Case Studies

Description: detailed information gathered over
time on a specific individual

Strength: provides descriptive data over a period
of time and analyzes new phenomena

Weakness: emotional attachment or personal
prejudice to subject can effect objectivity
Example:

Studying patients with gunshot wounds to
the head over a period of years to see how
injuries changed their behavior.
Survey
Description: a technique for gathering the selfreported attitudes, opinions, or behaviors of
people
Strengths:
1. easy administration, scoring, and statistical
analysis.

Weaknesses:
1. people lie or are opinionated
2. groups should be representative or data is
skewed
3. wording of question can sway answers


Example:
– Survey students about their opinions on
homework
Sampling when doing studies:

Representative samples are necessary
because you can’t survey everyone in a
given population.

Thus you create a random sample that
fairly represents a population. (Every person
in a group has an equal chance to
participate)

Ex. You want to survey the school
about attitudes on HW. By using a
students list where everyone is
numbered, you pick as many as
possible to participate.

The bigger the sample the better – as
long as it is representative.
M&M Activity
No, you may not eat
your candy. This is
an experiment.

All the packages together make up the
population from which we are getting the
_________
___________________,
representative sample which is each
individual package.

Each student who selected a pack of
M&M’s have selected a
random sample
_______________.

Separate the colors on the desk.
You should have according the
the Mars company,
30% brown
 20% red
 20% yellow
 10% green
 10% orange
 with a total of 24 M&M’s in a pack.

Correlational Method

Description: Used to look at relationships
between two variables.

Strengths: The stronger the correlation the
more successfully one variable can be
predicted from the other

Weaknesses: Does not est. cause and
effect. Often a 3rd (an intervening variable)
involved
Example

There is a positive
correlation showing
that people who go to
college will have
higher incomes.

an increase in one
variable tends to be
associated with an
increase in the other
Example 2

If an increase in one
variable tends to be
associated with a
decrease in the other
then this is known as a
negative correlation

There is a negative
correlation showing that
the more education a
person has the LESS
likely the are to be racist
Correlation and Causation
Scatterplot

A graph comprised of points that are
generated by values of two variables.

The slope of the points depict the direction,
while the amount of scatter depicts the
strength of the relationship.

Correlational coefficient: a statistical
measure of the degree of relatedness or
association between two sets of data that
ranges from -1 to 1.
Perfect
positive
correlation
Perfect
negative
correlation
No
relationship
What is the relationship between
height and temperament shown in
the scatterplot below?

It shows a moderate positive correlation.
+0.63
Experimental Method
Description: researcher manipulates a
variable under controlled conditions and
observes a response
 Strengths: Can establish cause and effect
relationships. Experiments should be able
to be replicated in order to be found valid
and reliable.
 Weakness: Because it is done under
controlled conditions hard to apply to real
world situation

Other types of studies

Longitudinal study – study one person
or event over a long period of time

Ex-post facto study – study something
after it happened naturally – look at
effect – seek cause
Statistics

Measures of central tendency – typical
scores
– Mean – average of scores
– Median: middle score in a rank
distribution
– Mode: most frequent score


Statistical procedures analyze and interpret
data allowing us to see what the unaided eye
misses.
Researchers are looking for statistical
significance
Measures of Variation
Range – difference between the
highest and lowest scores in a
distribution
 Standard deviation – a computed
measure of how much scores vary
around the mean (BELL CURVE)

A skewed distribution
Closure
Directions: For each of the following
hypotheses, explain which research method
would be best and why that method is best.
If a cancer patient receives chemotherapy, then
they will live longer than a cancer patient who
does not.
 Do people think coffee helps performance at
work?
 How does playing a high school sport effect
amount of friends you have?
 If there are no cars around, then most people do
not completely stop at a stop sign


If students study more, then they will do
better on tests.

What percentage of students actually use
the bathroom when they ask to go to the
bathroom?

Students behave differently around teachers.

How does laser eye surgery effect vision
later in life?