Some Practice Quizzes for Unit 2

• [Highly recommended] practice quizzes from our textbook publisher.  You will need to create an account (a very quick process).
• A quiz specifically on Research Methods.
• On this site, look under "Research Methods" to find three different quizzes for the unit.

Article Clarifying "Correlation vs. Causation"

Correlation and causation:  what does it all mean?

Psychology Today, 2010

Adi Jaffe, Ph D.

Being clear about inferences in research

Correlation

When researchers say they have found a “correlation," what they are saying is that they found a relationship between two or more variables. For instance, researchers have found a correlation between using marijuana as a teen and having more troublesome relationships in mid- to late-twenties.

Correlations can be positive, meaning that as one variable (marijuana smoking) goes up, so does the other (relationship trouble); or they can be negative, which would mean that as one variable goes up (methamphetamine smoking) another goes down (grade point average).  The trouble is that unless they are properly controlled for, there could be other variables affecting this relationship that the researchers don't know about.  For instance:  education, gender, and mental health issues could be behind the marijuana-relationship association.  (These variables were all controlled for by the researchers in that study.)

Researchers have at their disposal a number of sophisticated statistical tools to control for these, ranging from the relatively simple (like multiple regression) to the highly complex and involved (multi-level modeling and structural equation modeling).  These methods allow researchers to separate the effect of one variable from others, thereby leaving them more confident in making assertions about the true nature of the relationships they found.  Still, even under the best analysis circumstances, correlation is not the same as causation.

Causation

When an article says that causation was found, this means that the researchers found that changes in one variable they measured directly caused changes in the other.  An example would be research showing that jumping off a cliff directly causes great physical damage.  In order to do this, researchers would need to assign people to jump off a cliff and measure the amount of physical damage caused.  When they find that jumping off the cliff causes more damage, they can assert causality.  Good luck recruiting for that study!

Most of the research you read about indicates a correlation—NOT causation—between variables.  You can find the key words by carefully reading.  If the article says something like "men were found to have," or "women were more likely to," they're talking about correlation, not causation.

Why the difference?

The reason is that in order to actually be able to claim causation, the researchers have to split the participants into different groups and assign them the behavior they want to study (like taking a new drug), while the rest don't.  This is in fact what happens in clinical trials of medication because the FDA requires proof that the medication actually makes people better (more so than a placebo).  It's this random assignment to conditions that makes experiments suitable for the discovery of causality.  Unlike in correlational studies, random assignment assures (if everything is designed correctly) that it’s the behavior being studied, and not some other random effect, that is causing the outcome.

Obviously, it is much more difficult to prove causation than it is to prove an association.

So, should we just ignore correlation?

No!  Not at all!  Correlations are crucial for research and still need to be looked at and studied, especially in some areas of research like addiction.

The reason is simple:  we can't randomly give people drugs like methamphetamine as children and study their brain development to see how the stuff affects them, because that would be unethical.  So what we're left with is the study of what meth use (and use of other drugs) correlates with.  It's for this reason that researchers use special statistical methods to assess correlations, making certain that they are also considering other things that may be interfering with their results.

In the case of the marijuana article, the researchers ruled out a number of other interfering variables known to affect relationships, like aggression, gender, education, closeness with other family members, etc.  By doing so, they did their best to assure that the association found between marijuana and relationship status was real.  Obviously other possibilities exist, but as more researchers assess this relationship in different ways, we'll learn more about its true nature.

This is how research works.

It's also how we found out that smoking causes cancer:  through endlessly repeated findings showing an association. That turned out pretty well, I think ...

Unit 2 Calendar

Here's the plan for Unit 2:

Psychological Perpsectives

Another representation of the different psychological perspectives:

Textbook Website

Here is a link to the companion website for our textbook.  By doing a quick registration (name and email address), you will be able to access practice quizzes for each unit.

Practice Quizzes for Unit 1

Recommended practice quizzes to use in securing/checking retention of reading content and preparing for the Unit 1 exam:

• Learnerator Guide for AP Psychology (three separate quizzes for different topics within Unit 1; look under "History and Approaches")
• "Schools of Psychology" Quiz (all Unit 1)
• Thinkspot Chapter 1 Quiz (all Unit 1)

Here's the plan for Unit 1.

Monday 9/08          RTN 2 - 5

Tuesday 9/09         RTN 6 - 8

Thursday 9/11        Flashcards due
                               MULTIPLE CHOICE TEST

Friday 9/12            FRQ TEST

Notetaking & Study Recommendations

Per our discussion of research on note-taking, here are some (hopefully helpful) links and images.


1.  An article about Henry Roediger's research: "Science of learning book offers tips to ‘Make it Stick'"


2.  The full interview with Henry Roediger


3.  Cornell Notes guide:

4.  Matrix Notes sample (Something like this would go in the "Note-Taking Area" of your Cornell Notes.)

5.  Outline Notes sample (also in the "Note-Taking Area")