How do we know things?The Scientific Method

Psych 231: Research Methods in Psychology

Announcements

Why is this page upside down? Does the course webpage show up in

ReggieNet? Quiz 1 is due Friday Aug 21st @

midnight• Anybody try quiz 1 yet? Does it work okay?

Lab news This week labs are in their usual places,

next week they will be meeting in the library. Milner 164D computer classroom

The Science of Mythbusting

Accept the myth or Test the myth

Testable hypotheses – is the phenomenon something that can be observed and tested

Method – what is best way to make the observations to be tested?

Control groups – comparisons are key Replication – are you more likely to believe something that

happens once, or happens multiple times

Are elephants afraid of mice? long (~8 min)

Exercise: How do we know?

Write down two things that you “know”. Write down HOW you “know” those things.

“Greatest football team ever”

• Coach Bill Walsh

• Joe Montana & Jerry Rice

• 5 Superbowls

1981 1984 1988 1989 1994

Methods of Inquiry

Objective Subjective

Analysis

AcceptanceAuthority

Instruction

Regulation (rules & laws)

Tenacity

Faith

Intuition

Type of knowledge

Way

s of

kno

win

ghaving existence outside of a

person’s mind (“real”)existing in a person’s mind

Persuasion

Rationalism

Deduction

Our focus

Empiricism

Observation

Scientific Method

Reality is not this clear cut: Psychology uses objective techniques to examine what are often subjective things, so there are often some underlying assumptions that you need to keep in mind (later in the course: indirect measures, operational definitions)

Reality is not this clear cut: Psychology uses objective techniques to examine what are often subjective things, so there are often some underlying assumptions that you need to keep in mind (later in the course: indirect measures, operational definitions)

Methods of Inquiry

The Scientific Method A method used to test and analyze claims

about behavior Uses systematic observation and

experimentation 4 Cannons of the Scientific method:

• Empiricism, Determinism, Parsimony, Testability A 6 step process (your book breaks it into 7

slightly different steps, Figure 2.1)

Scientific Method

Step 1: Observation (Empiricism) Pay attention to the world around you, look for

generalizations

write down two generalizations that you have observed about people’s behavior

Two classes of generalizations• Descriptive generalizations – just describe how it is/what

was seen, how frequent, without making predictions• Cause and effect generalizations – makes predictions about

the observed relationship between two (or more) things.• (Determinism: phenomenon have identifiable causes)

Scientific Method

Step 2: Develop a theory or hypothesis Identify the variables associated with your

observations

Variables The characteristics of the behavior and the surrounding context

An explanation for the observed behavior(s)• How are the variables related to one another?

• May be based on past research, common sense, intuition, logic, etc.

Scientific Method

Step 3: Generate a testable prediction Testability: Need to specify how your hypothesis can

be tested through observation.• The relevant variables must be defined and observable.

Falsification is at the heart of the scientific method• Scientists don’t try to prove a theory, but rather set out to

refute (“disprove”) theories • Refutable hypotheses - must be stated in a way that allows

the potential for it to be wrongKarl Popper wiki

Scientific Method

Step 4: Make systematic observations Observational and experimental methods

• Which variables will we examine?• How do we measure these variables?• Which variables can we systematically manipulate?• What variables need to be controlled?• Were (from whom) will we collect the observations?

Scientific Method

Step 5: Evaluate your evidence Refutes theory Supports theory (not “proves the theory”) Leads to the revision of the theory Consider alternative theories

• There are always alternative explanations• Parsimony: Simple explanations are preferred over

more complex ones

Scientific Method

Step 6: Repeat

observations

hypotheses

predictions

systematicobservations

newhypotheses

predictions

systematicobservations

newhypotheses

Next time

Psychology as a science Developing your research ideas Reviewing the literature Moving from ideas to hypotheses

Chapter 2