week 2

PSY-101:
Principles of

Chapter 2

Chapter 2:
Psychological Research

WHY IS RESEARCH IMPORTANT?
● We need a way of knowing if our beliefs are

supported
● Research that uses the scientific method allows us

to make predictions based upon our beliefs, and
then observe whether or not those predictions come
true under controlled conditions
○ Allows us to separate fact from opinion so we

can make better decisions

THE SCIENTIFIC METHOD
Five main steps

1. Identify question of interest
2. Formulate an explanation (i.e., a theory)
3. Make a specific prediction (i.e., a hypothesis)
4. Collect and analyze data from an observation

or experiment
5. Communicate the findings (then back to step 1)

APPROACHES TO RESEARCH
The major research methods

● Case Study
● Naturalistic Observation
● Survey Research
● Correlational Methods
● Experimental Methods

CASE STUDY
● An in-depth, intensive investigation of a single

person or a small group
● Get LOTS of data about the condition being

studied
● However, can’t generalize findings to other

people

NATURALISTIC OBSERVATION
● Observe naturally occurring behavior

○ What do people actually do?
● Very valid (i.e., accurate) results
● However, no control over the study

○ The researcher just watches
● Researcher should be hidden and stay as

objective as possible

SURVEY RESEARCH
● A sample of people is chosen to represent a larger

group of interest (i.e., the population)
○ Asked a series of questions about their

knowledge, attitudes, or behaviors
● Ideally achieve a large representative sample

○ Allows for generalizations to the population
● We assume accurate self-report data

CORRELATIONAL METHODS
● Two variables are examined to determine

whether they are associated (or “correlated”)
○ As one variable changes, does the other

change along with it?
● Great for making predictions
● However, we CANNOT infer causality

EXPERIMENTAL METHODS
● Investigates the causal relationship between two

or more variables by:
1. Randomly splitting a sample into two groups
2. Changing one variable within only one of those

groups in a controlled situation
3. Observing the effects of that change by

comparing the two groups on another variable

EXPERIMENTAL METHODS
Independent Variable (IV)
● The thing that is changed (i.e., manipulated) by the

experimenter
● The two groups are made different ONLY on this variable

Dependent Variable (DV)
● The thing that is measured
● Expected to change along with changes of the IV
● We use this to compare the two groups after the manipulation

EXPERIMENTAL METHODS
Experimental group
● Receives the change (i.e., manipulated IV)
Control group
● Is not changed (i.e., no manipulated IV)

We compare the experimental group with the control group on the DV
to see if they’re different
● If different, we argue that the difference must have been due to the

manipulation (i.e., the changed IV caused the change in the DV)

RESEARCH ETHICS
Ethical Guidelines:
● Protect people from physical and mental harm
● Protect participants’ privacy
● Assure that participation is voluntary
● Inform participants about procedures

Research must be approved by an IRB (Institutional Review Board)
● An impartial committee convened to determine whether or not the

research study follows ethical guidelines
● Weren’t necessarily established until 1979

TO WRAP UP…
● NOT ALL RESEARCH IS SCIENTIFIC!
● Please be critical of everything you see and hear

○ Have some healthy skepticism
● Just because someone has done “research” in no

way implies that it was methodologically valid
research