The Scientific method

Psych 231: Research Methods in Psychology

Announcements & outline Chris has put together a course webpage

www.ilstu.edu/~cnwahlh/home (I’ve also posted a link on the course syllabus page)

If you are in his sections, please consult the page prior to going to lab

Today: The scientific method Problems getting a research idea Reviewing the literature

Methods of Inquiry

The scientific method A method used to test and analyze claims

about behavior Uses scientific methods of systematic

observation and experimentation.

Scientific Method write down two generalizations that you have

observed about people’s behavior. Step 1: Observation

Pay attention to the world around you, look for generalizations

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

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

the observed relationship between two (or more) things.

Scientific Method Step 2: Develop a theory or hypothesis

An explanation for the observed behavior(s)• May be based on past research, common sense, intuition,

logic, etc.

Scientific Method Step 3: Generate a testable prediction

Need to specify how your hypothesis can be tested. Falsification is at the heart of the scientific method

• More on this next lecture

Scientific Method Step 4: Make systematic observations

Observational and experimental methods• What are the relevant variables?• How do we measure the variables?• What needs to be controlled?

Much of the rest of this course deals with these

Scientific Method Step 5: Evaluate your evidence

Refutes theory Supports theory Leads to the revision of the theory Consider alternative theories

The importance of a critical eye There are always alternative explanations:

Psychic Uri Geller

Psychic watch repair Uri Geller, famous psychic. In Australia

(and other places), would “heal” watches in audiences and even over radio.

How did he do it? Geller’s claim: Psychic energy from him.

Psychic watch repair Problem:

Someone else replayed tape of the broadcast and found it worked then too

Alternative explanation: Old watches usually not working because oil

gummed up. Heat of hands is sufficient for a short time.

Experimental Solution: Add a control group

Scientific Method Step 6: Repeat

observations

hypotheses

predictions

systematicobservations

newhypotheses

predictions

systematicobservations

newhypotheses

Getting ideas for research

Classic barriers Where do they

come from? What is a “good”

idea?

Classic barriers to good research ideas

I’m not smart enough. Yes you are, but it may be hard work

Classic barriers to good research ideas

I’m not smart enough. Somebody else must have already done this.

• review the literature, if somebody has done it remember two things:

• replication is an important part of science• perhaps there is a new angle to add to the research

idea

Classic barriers to good research ideas

I’m not smart enough. Somebody else must have already done this. I don’t know how to pursue the idea.

again, review the literature, how have others examined similar issues

Classic barriers to good research ideas

I’m not smart enough. Somebody else must have already done this. I don’t know how to pursue the idea. It’s too simple, something must be wrong.

Parsimony (simplicity) is generally a GOOD thing

Classic barriers to good research ideas

I’m not smart enough. Somebody else must have already done this. I don’t know how to pursue the idea. It’s too simple, something must be wrong. The idea will take too much work.

don’t be afraid to work hard sometimes you can think of ways to simplify things to

reduce the workload

Classic barriers to good research ideas

I’m not smart enough. Somebody else must have already done this. I don’t know how to pursue the idea. It’s too simple, something must be wrong. The idea will take too much work.

Our goal is that you come away from this course with the knowledge and ability to see past these pitfalls.

Why review the literature What is the underlying motivation(s) for doing a review

of the literature? Getting ideas. What has been done, what hasn’t been done? Avoid past mistakes. Understanding the relevant theories. What variables are important?

What is the literature? Primary Sources - essentially reading the original

report Journal articles Edited books (sometimes) Professional meetings Electronic publishing (fairly new, pluses and minuses) Faculty members & other personal communications

Secondary Sources - reading a report of the report Literature Reviews

Psychological Bulletin, Annual Review of Psychology Text books Citations in books and articles

What is the literature? Secondary Sources:

Advantages: • Good starting place• Often reviews a lot of relevant literature• Relatively brief descriptions

Disadvantages:• Somebody else’s description

• May be incorrect • May be biased

• Not enough detail

Next week

How to review the literature & evaluating your research ideas

Read chapter 2 this weekend