I have written a few times about factors that affect
willpower. Willpower is the name that we
give to the mechanisms (most of which involve the frontal lobes of the brain)
that prevent us from carrying out a behavior we really want to perform.
Over the past several years, there have been a number of
studies showing that if you make people work hard to control their behavior,
then they have difficulty continuing to use willpower in a later situation that
calls for preventing behavior. The idea
that willpower is a resource that can be used up is called ego-depletion. It has been
studied extensively by Roy Baumeister, Kathleen Vohs and their colleagues.
A paper by Veronika Job, Carol Dweck, and Gregory Walton in
the November, 2010 issue of Psychological
Science suggests that one factor that affects whether you show
ego-depletion effects is whether you believe that willpower is a limited
resource.
In one study, they asked people a number of questions about
willpower. Some people gave answers
suggesting that they believe that willpower is a limited resource. Other people gave answers suggesting that
willpower is actually an unlimited resource.
Later in the study, people did a difficult task that was
either relatively easy or one that was hard.
The easy task involved crossing out all of the letter es on a page of
written text. The harder task asked
people cross out all of the ‘e’s for a while, and then switch so that they
crossed out every ‘e’ except for the ones that were followed by another
vowel. This task is difficult, because
people have to prevent themselves from doing a behavior that they had already
built up some habit to perform.
After doing this task, people performed a Stroop task. In the Stroop task, people see words naming
colors that are written in a colored font.
People have particular difficulty naming the color of the font when the
word is the name of a different color.
For example, people are prone to make mistakes when they see the word “yellow”
written in red font.
Putting all this together, people who believed that
willpower is a limited resource made more mistakes on the Stroop task following
the difficult letter-crossing task than following the easy letter-crossing
task. That is, these people showed the
typical ego-depletion effect where doing one difficult self-control task makes
it hard to do a second.
In contrast, the people who believed that willpower is
essentially unlimited did equally well no matter which letter-crossing task
they did. That is, those people who
think that willpower is unlimited did not show the ego-depletion effect.
Now, it is possible that there are just differences between
people. Some people have limited
willpower resources and others don’t. On
that view, it isn’t that your beliefs about willpower affect your performance,
but rather that your beliefs about willpower reflect your actual abilities.
To explore this possibility, a second study actually
manipulated people’s beliefs about willpower by using a biased
questionnaire. One version of the
questionnaire got people to agree with statements suggesting that willpower is
a limited resource (“Working on a strenuous mental task can make you feel tired
so that you need a break before accomplishing a new task.”) A second version used a questionnaire that
got people to agree with statements suggesting that willpower is unlimited
(“Sometimes working on a strenuous mental task can make you feel energized for
further challenging activities.”)
After these questionnaires, the groups did the same tasks as
before.
In this study, the group that was biased to believe that
willpower is limited did more poorly on the Stroop task following the difficult
letter-crossing task than following the easy one. In contrast, the group that was biased to
believe that willpower is unlimited did just as well on the Stroop task
regardless of which letter-crossing task they did.
Taken together, these studies suggest that people’s beliefs
about their own willpower are one factor that affects how effective their
willpower will be. The more that you
believe that willpower can keep you from doing things that you don’t want to
do, the more likely you will be to use your willpower successfully.
All this suggests that it is well worth believing in
willpower.
