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How Rewards Change Human Behavior
What
happens if someone suddenly gives us money or a prize for doing something we
really love and enjoy? Generally, we would think we would get even more
excited. However, human psychology shows us a strange truth that is exactly the
opposite.
When we do
something we love and receive an external reward in return, our true intrinsic
motivation (inner drive) to do that task drops significantly. In the world of
psychology, this interesting phenomenon is called the 'Overjustification
Effect'.
For
example, let's say you really love playing volleyball. You play it purely for
fun, without looking for any profit. Now, suppose you are paid to play the
exact same game. According to this effect, your natural interest in the game
will slowly begin to decrease.
Why do
rewards, which are supposed to boost our interest, actually lower our inner
motivation? Why does this 'Overjustification Effect' happen? What lessons do
the scientific psychological studies conducted on this topic teach us? We will
see detailed answers to these questions in this article. Through this, we can
clearly understand why our motivation level drops when we get a reward for
doing something that brings us joy.
01. Impact of the Overjustification Effect
This overjustification effect is not just a theoretical
concept; it can cause a very deep and serious impact on our daily activities
and behaviors.
1. Completely Giving Up on Favorite Activities
The worst negative effect of this is that once a person
starts getting money or some other reward for an activity that brought them
immense joy, they might completely stop doing it. This happens because when
something started for pure happiness turns into something done just for profit,
the hold it has on them slips away.
2. Cognitive Evaluation Theory
According to psychologist Edward Deci, the 'Cognitive
Evaluation Theory' clearly explains why humans lose their motivation when they
receive money as a reward.
In the
Self-Determination Theory, there is a very important concept called 'Autonomy'.
That is, autonomy is the freedom of a person to independently choose and do an
activity without any external pressures and controls. However, when money is
given as a reward for a task, it takes away this "freedom of external
constraints" from people.
Deci's Famous Puzzle Experiment
This
was proven very clearly in the early experiments conducted by Edward Deci. He
carried out this study using two groups of people:
- First Group (Unpaid): Solved a
puzzle purely for entertainment and joy. They felt complete mental
freedom.
- Second Group (Paid): Were given money to solve the same puzzle, along with the pressure to perform well.
At the end
of this experiment, Deci found that money and performance-related pressures
create strict limitations within a person and kill their natural interest.
To put it simply, when you put a price tag on an art or talent that should spread its wings freely, it becomes like a bird trapped in a cage. (1,2)
02. Other Key Research on the Overjustification Effect
A few more famous psychological studies were conducted to
prove how this overjustification effect works in children and within our
education system. Here are the interesting facts they tell us:
1. Mark Lepper's Study with Children
Psychologist Mark Lepper conducted a famous study with
children. He asked some children to draw pictures using 'Magic Markers'. In this, a pre-arranged agreement
was made with one group of children that if they drew, they would be given a
"Good Player Award" certificate and a prize. This prize acted as an
external incentive (Extrinsic Motivation). Another group of children was not
promised any prize; they drew purely for their own joy.
The Result of the Study:
The
children who drew expecting a prize showed very little interest in drawing and
also put less effort into it. On the other hand, the children who drew purely
for fun without any reward did so with great interest and dedication.
2. Praise Style and Mindset (Effort vs. Ability Praise)
In another interesting study centered on children, it was
found that the way we praise them determines their future success:
- Praising
Ability: When you praise a child's inherent talent by saying, "You
are so smart!", it creates a state of stagnation in their mind.
- Praising
Effort: Instead, when you praise their effort by saying, "You worked
really hard on this!", they develop a new mindset.
Children who are praised based on their effort in this
manner deeply believe that success is not a talent one is born with, but rather
depends on the hard work we put in. These children with a 'Growth Mindset' do
not get discouraged when obstacles and failures come their way in life;
instead, they gain the courage to face them and keep fighting.
3. Performance-Contingent Reinforcers
Most importantly, researchers have also found an
exception: not all external rewards decrease intrinsic motivation. When a
reward depends on "how well we do a task" rather than just doing it
as a mere chore, this overjustification effect does not come into play.
For example, take a student's exam grades: a grade is not
given for simply sitting around. It is awarded purely on the basis of
'performance'—how well a student studied and how excellently they wrote the
exam.
Instead of causing a person to study just for the sake of obligation, these kinds of performance-contingent rewards stimulate their inner intrinsic motivation to study even better, and never diminish it. (3,4,5)
03. The First Historical Experiment to Prove the Overjustification Effect
In the 1970s, Edward Deci, a psychology professor at the
University of Rochester in New York, conducted a series of three consecutive
experiments using college students to prove this effect. Let's look at how his
highly significant first experiment (Experiment One) was planned and what its
results were.
The First Experiment: Cube Puzzles and College Students
For his first experiment, Deci selected 24 students studying
in an introductory psychology class. They were told, "This is an
experiment examining your problem-solving concepts."
The students were given 1-inch wooden blocks (cubes). They
had to use these blocks to replicate certain shapes drawn on paper within 13
minutes. (In the history of psychology, this is known as the famous 'Soma
Puzzle').
This experiment was conducted by dividing it into three main
stages (Sessions):
1. First Session: Equal Start – Measuring Intrinsic
Motivation
In this stage, no reward (money or prize) was given to
either of the two groups. The students solved the puzzles based solely on their
natural, inherent interest.
2. Second Session: Introduction of Monetary Incentive –
Separation and Analysis
Now, the students were split into two separate groups.
3. Third Session: Stopping the Reward – Discovering the
Effect
In this final stage, no money was given to either group.
The money for the rewarded group was cut off, citing reasons such as "the
budget has run out."
The Researcher's Secret Strategy (The Secret Observation)
During
each session, Professor Deci employed a clever tactic. While the experiment was
underway, he left the room for 8 minutes under the pretext of having some other
work to attend to. Before leaving, he told the students, "You can do
whatever you want until I get back (you can rest, read the magazines over
there, or continue playing with the puzzles)."
However,
he was actually watching the students closely through a one-way mirror during
that 8-minute break. His true objective was to measure exactly how much time
the students chose to spend playing with the puzzle entirely of their own free
will.
Fascinating Results of the Experiment
|
Experimental
Session |
Control
Group (Unpaid) |
Reward
Group (Paid) |
|
Session
1 (No money involved) |
Continued
to play with the puzzle enthusiastically during the break. |
Played
with the puzzle enthusiastically, on par with the control group. |
|
Session
2 (When money was given) |
Spent
the same amount of time with the puzzle as usual. |
Spent
more time trying to solve the puzzle (driven by the monetary incentive). |
|
Session
3 (When money was stopped) |
Continued
to play without losing their natural, inherent interest. |
Their
interest in the puzzle dropped drastically. They completely stopped playing
during the break. |
Professor Deci's Conclusion:
This
experiment made it crystal clear that when external rewards (money) are
introduced and then suddenly removed, a person's intrinsic motivation hits rock
bottom.
However,
because the number of students who participated in this experiment was very low
(24 people), more extensive research was needed to officially confirm this
conclusion. As a follow-up, the subsequent experiments he conducted brought
even more fascinating facts to light.
Experiment Two: An Interesting Field Study in the Real World
Deci
planned to investigate how this overjustification effect works in a real-world
setting (field study), moving beyond a controlled laboratory environment. For
this purpose, he chose a college newspaper office.
Design and Stages of the Experiment
Eight
students who wrote headlines for the college newspaper participated in this
experiment. The study was conducted during the final 10 weeks of the
newspaper's production cycle. These 10 weeks were divided into three periods as
follows:
- First Stage: 4 weeks
- Second Stage: 3 weeks
- Third Stage: 3 weeks
The
students were divided into two groups based on the days they worked:
Group
Classification and Rewards
|
Group
Type |
Working
Days |
Reward
Provided (Money) |
|
Experimental
Group |
Tuesday
editions |
Paid
at a rate of $0.50 per headline only during the second stage. (No money was
given during the first and third stages). |
|
Control
Group |
Friday
editions |
No
money was provided to them at any stage of the experiment. |
Secretly Measured 'Interest'
An
interesting tactic was employed in this experiment. The time students took to
write the headlines was secretly recorded without their knowledge. In
psychology, this method is called unobtrusive measurement. Thanks to this, the
students behaved naturally without the anxiety of knowing they were being
watched. Their motivation level towards their work was calculated based
entirely on the speed with which they wrote the headlines.
The Truth Revealed by the Results
At the
end of the experiment, a significant difference was observed in the performance
of the two groups:
- Control Group (Unpaid): Their
performance steadily improved step-by-step from the first stage to the
final stage. As they gained more experience, their speed naturally
increased.
- Experimental Group (Paid): In
the second stage when they were paid, their headline-writing speed
increased slightly. However, in the third stage, as soon as the monetary
reward was stopped, their speed and performance plummeted lower than ever
before.
The Psychological Fact:
The
overjustification effect was proven once again through this field study. This
college newspaper study clearly shows us that temporary monetary rewards
introduced midway can disrupt our long-term effort and interest, far more than
the drive we initially have within ourselves to do a task.
Experiment Three:
In his
previous two experiments, Edward Deci investigated the impact of rewards using
money as the primary incentive. However, what kind of impact do verbal praise
and encouraging words—excluding money—have on human psychology? He designed his
third experiment to understand exactly that.
The Power of Words and the Excellence of Praise (Experiment Three)
In
terms of design, Deci's third experiment was identical to his first one. Here
too, 24 students from an introductory psychology class participated. They were
divided equally, with half assigned to the Experimental Group and the remaining
half to the Control Group.
A New Strategy: Praise Instead of Money!
Deci
introduced a key change in this experiment. During the second session (Session
Two), instead of giving money to the experimental group, he offered verbal
praise and positive comments (Verbal Reinforcements & Positive Feedback).
- Regardless of whether the
students successfully solved the puzzle or not, they were praised for the
efforts they put in (for example: "Excellent effort!", "You
are approaching this very meticulously!").
- At the same time, the control
group, as usual, received no praise or rewards whatsoever.
Just
like the previous experiments, the amount of time the students voluntarily
spent playing with the puzzle during the break was secretly monitored this time
as well.
The Surprising Results of the Experiment
The
behavior of the students who received praise yielded completely different,
positive results compared to the previous experiments:
Experimental
Groups and Behavioral Changes
|
Experimental
Groups |
Changes
Observed During the Experiment |
|
Experimental
Group (Praised) |
During
the 8-minute free break, the time they spent with the puzzle did not decrease
at all. In fact, their interest in solving the puzzle actually increased
slightly during the second session when the praise was delivered. |
|
Control
Group (Unpraised) |
Their
interest steadily declined as each session of the experiment passed. |
The Great Truth Professor Deci Told the World
Based
on the results of these experiments, Professor Edward Deci proclaimed two
highly crucial truths regarding human motivation to the world:
- The Positive Drive of Words:
Verbal praise and positive feedback that acknowledge a person's effort
increase their intrinsic motivation. Words achieve what money fails to do!
- The Long-Term Impact of Money:
Financial rewards offered on the basis of money destroy a person's natural
interest and cause that decline in interest to persist for a very long
time.
Final Thought:
Professor Deci's trilogy of experiments firmly makes us realize that we do not need to open our wallets to motivate someone; just two genuine kind words recognizing their effort are more than enough to awaken their inner drive to work hard.
04. Why Does the Overjustification Effect Occur? (Theories Behind It)
Researchers have discovered that when we receive money or a
prize for an activity we already enjoy doing, our intrinsic interest to perform
that action in the future decreases.
But how exactly does a reward diminish our genuine
motivation? Here are three major theories that explain the psychological
reasons behind this:
Here is the English translation of the text:
1. Over-attribution Theory: Excessive Focus on the Reward
According to basic human psychology, when an external reward
enters the picture during an activity, our brain automatically focuses its
attention on the thing that is easily visible.
- The
Shift: Instead of focusing on how much we enjoy performing the activity,
our attention shifts to the money or prize we are going to receive.
- The
Outcome: As a result, rather than thinking, "I am doing this activity
because I enjoy it," our mind mistakenly constructs a reason for it (over-attribution),
thinking, "I am doing this only for the sake of this external
reward."
2. The Feeling of 'Bribery' and Coercion
Another interesting explanation is that people sometimes
view external rewards as a coercive force.
- The
Shift: The reward given to us creates an internal feeling as if we are
being forced to do the task, or as if we are being "bribed" to
get the work done.
- The Outcome: Because our mind begins to consider that "we are not doing this work freely; we are doing it for some external pressure," our natural interest fades away.
3. Cognitive Evaluation Theory (CET)
A sub-theory of Self-Determination Theory, 'Cognitive
Evaluation Theory' states that external rewards directly strip away a person's
sense of 'Autonomy'.
Psychologically, for a person to engage in an activity with
complete interest, three core psychological needs must be satisfied:
Core Psychological Needs
|
Need |
Explanation |
|
Autonomy |
The freedom to make choices voluntarily, without any
external pressure or constraints. |
|
Competence |
The self-confidence that we can perform a task effectively
and skillfully. |
|
Relatedness |
The sense of satisfaction that we are connected with other
people and that we belong as a part of a community. |
Key Concept of CET:
External rewards break down the sense of freedom found in 'Autonomy', which is the most crucial of these three pillars. When we feel like we are losing control over our own actions, the level of our inherent, inner motivation naturally shrinks as well. (6,7,8,9)
Key Takeaways: Things to Keep in Mind
Here are the three most critical lessons we must learn from
this overjustification effect:
- Interest
is the Motivation, Not the Reward: External rewards (such as money and
prizes) given for an activity that we already like and enjoy doing will,
over time, diminish our natural interest and engagement in that activity.
- When
the Purpose Changes, the Interest Shifts: Our brain easily gets distracted
when rewards are introduced. The noble thought of "we are doing this
activity because we love it" disappears, and the narrow mindset of
"doing it solely for the reward" begins to take over. This ruins
our inner satisfaction.
- Freedom is the Lifeblood of Motivation: Autonomy (the feeling of acting freely) is absolutely essential for us to gain complete motivation to do a task. However, external pressures and rewards strip away this sense of freedom from us, leaving us feeling as if we are under a heavy burden.
Final Thought:
Whether you wish to nurture an art form, master a new skill,
or teach your children new habits—kind words that recognize their effort and
the freedom for them to act voluntarily will safeguard their interest for a
lifetime, far better than money or prizes!
References.
1. Cerasoli, Nicklin, & Ford (2014)
Cerasoli, C. P., Nicklin, J. M., & Ford, M. T. (2014).
Intrinsic motivation and extrinsic incentives jointly predict performance: A
40-year meta-analysis. Psychological Bulletin, 140(4), 980–1008. https://doi.org/10.1037/a0035661
2. Deci (1971)
Deci, E. L. (1971). Effects of externally mediated rewards
on intrinsic motivation. Journal of Personality and Social Psychology, 18(1),
105–115. https://doi.org/10.1037/h0030644
3. Gunderson et al. (2018)
Gunderson, E. A., Sorhagen, N. S., Gripshover, S. J., Dweck,
C. S., Goldin-Meadow, S., & Levine, S. C. (2018). Parent praise to toddlers
predicts fourth grade academic achievement via children’s growth mindset. Developmental
Psychology, 54(3), 432–441. https://doi.org/10.1037/dev0000444
4. Levy et al. (2016)
Levy, A., DeLeon, I. G., Martinez, C. K., Fernandez, N. H.,
Gage, N. A., Sigurdsson, S. Ó., & Frank-Crawford, M. A. (2016). A
quantitative review of overjustification effects in persons with intellectual
and developmental disabilities. Journal of Applied Behavior Analysis, 50(1),
206–221. https://doi.org/10.1002/jaba.359
5. Martela & Riekki (2018)
Martela, F., & Riekki, T. J. (2018). Autonomy,
competence, relatedness, and beneficence: A multicultural comparison of the
four pathways to meaningful work. Frontiers in Psychology, 9,
Article 1157. https://doi.org/10.3389/fpsyg.2018.01157
6. Morris et al. (2022)
Morris, L. S., Grehl, M. M., Rutter, S. B., Mehta, M., &
Westwater, M. L. (2022). On what motivates us: A detailed review of intrinsic
v. extrinsic motivation. Psychological Medicine, 52(10),
1801–1816. https://doi.org/10.1017/s0033291722001611
7. Riley (2016)
Riley, G. (2016). The role of self-determination theory and
cognitive evaluation theory in home education. Cogent Education, 3(1),
Article 1163651. https://doi.org/10.1080/2331186x.2016.1163651
8. Stanford University (2018) — News Article
Stanford University. (2018, March 12). Mark Lepper:
Intrinsic motivation, extrinsic motivation, and process learning. Bing
Nursery School. https://bingschool.stanford.edu/news/mark-lepper-intrinsic-motivation-extrinsic-motivation-and-process-learning
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