Evaluating a Theory: PEAR

After doing lots of research on a topic, Psychologists may come up with a theory of behavior.  What is a theory in Psychology, and how can we tell the difference between a strong and weak theory?  That's the focus of this page. 
Try it Out: Mindset 

According to Carol Dweck, there are two kinds of mindsets: fixed and growth.  Which mindset do you have?  Take this quiz  to find out.

Now watch the video below to learn about these two mindsets, and the differences between them.  Make a list of all the differences between the fixed and growth mindset.
What is a Theory?

According to Dweck, there are two ways the people think about their talents.  People with a fixed mindset believe their intelligence and abilities are determined by birth.  According to these people, you are either naturally good at something - or you aren't.  On the other hand, people with a growth mindset believe that ability is something that must be developed.  Consequently, people with a growth mindset keep trying hard, even when a task seems impossible, because they believe they can get better and better through practice.  People with a fixed mindset, on the other hand, tend to give up in the face of challenge, because they get discouraged with difficulty and believe they just aren't talented or good enough to succeed.

The concept of two mindsets is an example of a theory in Psychology.  A theory provides a model for understanding people's thoughts, emotions and behaviors.  A good theory does two things: it explains people's behaviors, and it also makes predictions about how they will behave in the future.  Theories in Psychology are built on constructs, which are explanatory variables that are not directly observable.  For example, in Dweck's theory, fixed and growth mindsets are constructs of the theory.  Other well-known constructs in Psychology theories include intelligence, motivation, and personality. We can't actually cut open someone's brain and "see" a fixed or a growth mindset, the way a surgeon can cut open someone's chest and observe their heart.  Nonetheless, the concepts of fixed and growth mindsets are useful because they help explain and predict behavior.

Think Critically: Explaining & Predicting

1.  Sarah was the best in her class in Primary School Math.  She always got top marks on her Math tests, even though she rarely studied.  All of Sarah's Math teachers said she had a natural gift for numbers.  However, as Sarah grew up, and went on to high school, she began to find Calculas really difficult.  Her Math grades dropped sharply, and Sarah started getting discouraged.  She began to think that Math wasn't her strength, after all, and started neglecting her Math homework, spending more time on other subjects.  How does Dweck's Mindset theory explain Sarah's behavior?

2.  Steve was always interested in computers and technology, and rarely spent much time on anything else.  But when Steve went to college, he decided that he really wanted to learn to play the guitar.  Steve never played an instrument before, and knew very little about music.  However, Steve believes that he can pick up any skill, as long as he practices hard enough.  Steve found a guitar teacher through Craigslist, and just had his first guitar lesson.  It was a difficult first lesson.  The guitar felt awkward in his hands, and plucking at strings felt unnatural.  Will Steve give up, or carry on with his lessons?  What does Dweck's Mindset theory predict Steve will do?

Scroll to the bottom of the page for answers

Evaluate a Theory with PEAR

Not all theories in Psychology are good theories.  To help evaluate the strengths and limitations of a theory, remember PEAR.

  • P stands for Predict.  Does the theory make testable predictions about human behavior?
  • E stands for Explain.  Does the theory provide a convincing explanation for behavior?
  • A stands for Applicability.  Is the theory useful in the real world?  Can it be applied to help people?
  • stands for Research Evidence.  Has credible research been carried out in support of the theory?

A good theory must provide a logical, reasonable and convincing explanation of why people behave in a certain way.  But a good theory must not be limited to explaining the past.  A strong theory should also be capable of making predictions about the future, and these predictions should be testable - we should be able to check if the predictions are accurate or not.  For instance, Mindset theory predicts that people with a growth mindset will keep working hard on a tough problem, while people with a fixed mindset will give up quickly.  We could test this prediction by comparing how long people with fixed and growth mindsets spend working on a difficult challenge.

Moreover, a good theory is useful.  It can be be applied to help people in some way, or to solve a problem in the world.  This is where Mindset theory really shines.  If teachers and parents can help their children adopt a growth mindset, then they will tend to practice hard, peresvere in the face of obstacles, and develop their talents through hard work.  Mindset theory is something that can be applied to improve people's lives.

Finally, because Psychology is a Science, a theory must be supported by Research Evidence before it is accepted.  For instance, research can be carried out by testing the predictions made by the theory.  When dozens (or even hundreds) of studies consistently confirm the predictions of a theory, then the theory will gain greater acceptance.   Dweck (and other researchers) have carried out a large number of studies in support of Mindset theory, one of which you'll learn about below.  

Video Activity: Research on Mindset Theory

What determines whether a child develops a fixed or a growth mindset?  According to Dweck, one answer is how children are praised.  If a child is always praised for being smart, they will tend to develop a fixed mindset, believing that success or failure depends on natural intelligence.  On the other hand, if a child is regularly praised for their effort, they will tend to develop a growth mindset, associating hard work with success.

In the video below, you'll see a simple experiment, in which Dweck puts this prediction to the test.  Watch the video below, and answer the following questions:

1.  What research method does this study utilize?

2.  What are the independent and dependent variables?

3.  Identify one strength and one limitation of this study

Scroll to the bottom of the page for answers

Exam Tip: Evaluation 

When writing an essay about a theory, you should first describe the theory, explaining its constructs and processes.  Then, you also need to evaluate the theory, based on PEAR.  When discussing the Reseach Evidence for a theory, the strengths and limitations of the research are also relevant in evaluating the theory.  If a theory has lots of strong supporting research, then this suggests the theory is sound.  On the other hand, if there are lots of problems or limitations in the research, then perhaps the theory itself is open to question.  To recap,

  • Step 1: Explain the theory

  • Step 2: Describe the supporting research (Aim, Procedure, Findings, & Conclusion) 

  • Step 3: Evaluate the supporting research (GRAVE)

  • Step 4: Evaluate the theory (PEAR), making reference to the strengths and limitations of the supporting research in your evaluation


  • I can describe a theory by discussing its constructs, processes and assumptions

  • I can evaluate a theory by assessing how well it explains & predicts behavior

  • I can evaluate a theory based on how useful it is in real life
  • I can evaluate the quantity and quality of research evidence in support of a theory
Quiz Yourself!

1.  What is a construct in a Psychological theory?

(a) An explanatory variable that is directly observable

(b) An explanatory variable that is not directly observable

(c) An explanatory research study that is directly observable

(d) An explanatory research study that is not directly observable

2.  A good theory in Psychology should..

(a) Manipulate an independent variable and measure a dependent variable

(b) Control all extraneous variables

(c) Have high replicability

(d) Make testable predictions about human behavior

3.  According to a theory by Gottman, healthy communication is the most important factor for marriages to work.  If this theory has predictive power, Gottman should be able to...

(a) Offer effective counselling to couples to improve their relationship

(b) Identify which couples will divorce, based on how they communicate

(c) Identify the communication style used by each couple

(d) Judge which person was most responsible for a failed relationship

4.  A theory has high applicability if it is capable of...

(a) Making testable predictions

(b) Explaining behavior

(c) Being supported by a large body of research evidence

(d) Making a difference in the real world

5.  A theory has been supported by dozens of research studies.  However, all of the research has been carried out on American college students.  What can be said of the theory?

(a) It may not apply to other populations

(b) It may lack ecological validity

(c) It may not be applicable to real life situations

(d) It may not be based on constructs

Think Critically - Explaining & Prediction

1.  Sarah has a fixed mindset.  She once believed she had a natural gift at Math, and so expected to excel in the subject without much effort.  As soon as Sarah ran into obstacles, she began to doubt her talents, and began questioning whether she was smart enough to succeed.  Instead of working hard to develop her Math skills, Sarah gives up at the first experience of difficulty, because to her that's a sign that she isn't so talented, after all.

2.  Because Steve has a growth mindset, he believes that he can develop and grow new skills.  Although Steve knows that he isn't good at playing the guitar right now, he is confident that he could become a skilled musician with enough determination and practice.  Therefore, Mindset Theory predicts that Steve will carry on with his guitar lessons, despite the difficulty of learning the instrument.

Research on Mindset Theory

1.  This study is a lab experiment.

2.  The independant variable is the type of praise that children receive (praise for effort vs. praise for ability) and the dependent variable is how children respond to the difficult puzzle (how long they continue working on them, and whether they ask for more easy or difficult puzzles).

3.  A strength is that variables are carefully manipulated and controlled.  For instance, the same wording is used for all participants, both in the praise they are given in each condition, and when presented with a choice of easy or difficult puzzles.  A limitation is that participants are all 9 and 10 year old, so more research would have to be carried out to see if these results apply to younger and older children.

Quiz Yourself

1 - B, 2 - D, 3 - B, 4 - D, 5 - A