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Definition:

A variable is something that can have different amounts or different types.

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Examples of Variables

“Energy levels” is a variable. I can have different levels on different days, and I can have different levels than you have.

“Favorite color” is a variable. My favorite color usually is “red,” but on some days I change my mind and it’s “green.”

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Goals of Psychology

1. Describe behavior. 2. Predict behavior. 3. Explain behavior. 4. Optimize behavior.

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GOAL #1 - DESCRIBE

DESCRIBE = List the characteristics of the behavior (or person).– How many? Or How much? Or What

color? etc.– Addresses one variable at a time, never

the relationship between two variables.

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GOAL #2 - PREDICT

Knowledge about one variable is used to make an educated guess about a second variable.

Example: I predict that if someone’s wearing a swim suit, she’ll soon be eating ice cream.

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PREDICT (cont’)

Predicting is made possible when– 1. we know that one variable causes the second

one. Example: Studying affects math grades.

– 2. we know that one variable tends to be seen along with the second variable. (They’re correlated.)

Wearing swim suits corresponds to eating ice cream.

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PREDICT (cont’)

Unlike when we describe, when we predict, we always are utilizing two (or more) variables.

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GOAL #3 - EXPLAIN

Find out if one thing produces another thing.

Does a change in variable X lead to a change in variable Y?

Explain = Cause & Effect

To explain is to say/know why the effect happens.

All of the above are other ways to say “explaining behavior”.

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Goal #3 - EXPLAIN (CONT’)

Just like when we’re predicting, when we explain, we’re always utilizing two (or more) variables.

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GOAL #4 - OPTIMIZE

To improve behavior, relationships, etc. To create the best behavior we can. To help.

Many textbooks will word this more neutrally/negatively as “To Control.”

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RELATING THE GOALS TO RESEARCH METHODS

Generally, when we want to– describe, we use a survey or observational study,

and when we want to– predict, only, we use a correlational study.

Important point ALWAYS, when we plan to use research results to

explain, we must use a study called an experiment (also referred to as experimental design or an experimental study, etc.)

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EXPLAINING: EXPERIMENTS

An experiment is the only study that can tell us about cause & effect because it is the only study that eliminates all but one possible cause for the effect.

This statement is a short version of the main point. I will elaborate in a separate power point.

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EXPLAINING: EXPERIMENTS

Only One Possible Cause – An Example

Lets say I clone a woman 100 times. I then take every other clone, and give her a short dress to wear. The remaining clones get exactly the same style dress, but it’s longer. I then ask all of the women to fill out a questionnaire asking them how “feminine” they feel. My hypothesis is that shorter dresses (the cause) lead women to feel more feminine (the effect). If I find this to be true, I can conclude that it was the length of the dress, AND NOTHING ELSE, that produced the more feminine feelings.

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EXPLAINING: EXPERIMENTS

How do I know it was the dress? Maybe the women in the “short dress” group had more estrogen, and that’s why they felt more feminine. Nope. That’s not it.

I know it was the dress because I had 100 identical clones. Since the women were identical, and we treated both groups exactly the same, IT HAS TO BE THE DRESS that accounts for the two groups feeling two different levels of femininity.

(The more this makes sense to you, the easier time you’ll have with the next power point. Go over this one again until you feel really comfortable.)