The Frontal Cortex

Willpower

Posted by Jonah Lehrer on December 28, 2009
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Apologies for the light blogging: I’m enjoying a little vacation from my computer. But here is a recent little article about willpower in the WSJ:

Willpower, like a bicep, can only exert itself so long before it gives out; it’s an extremely limited mental resource.

Given its limitations, New Year’s resolutions are exactly the wrong way to change our behavior. It makes no sense to try to quit smoking and lose weight at the same time, or to clean the apartment and give up wine in the same month. Instead, we should respect the feebleness of self-control, and spread our resolutions out over the entire year. Human routines are stubborn things, which helps explain why 88% of all resolutions end in failure, according to a 2007 survey of over 3,000 people conducted by the British psychologist Richard Wiseman. Bad habits are hard to break–and they’re impossible to break if we try to break them all at once.

Some simple tricks can help. The first step is self-awareness: The only way to fix willpower flaws is to know about them. Only then can the right mental muscles get strengthened, making it easier to succeed at our annual ritual of self-improvement.

The brain area largely responsible for willpower, the prefrontal cortex, is located just behind the forehead. While this bit of tissue has greatly expanded during human evolution, it probably hasn’t expanded enough. That’s because the prefrontal cortex has many other things to worry about besides New Year’s resolutions. For instance, scientists have discovered that this chunk of cortex is also in charge of keeping us focused, handling short-term memory and solving abstract problems. Asking it to lose weight is often asking it to do one thing too many.

In one experiment, led by Baba Shiv at Stanford University, several dozen undergraduates were divided into two groups. One group was given a two-digit number to remember, while the second group was given a seven-digit number. Then they were told to walk down the hall, where they were presented with two different snack options: a slice of chocolate cake or a bowl of fruit salad.

Here’s where the results get weird. The students with seven digits to remember were nearly twice as likely to choose the cake as students given two digits. The reason, according to Prof. Shiv, is that those extra numbers took up valuable space in the brain–they were a “cognitive load”–making it that much harder to resist a decadent dessert. In other words, willpower is so weak, and the prefrontal cortex is so overtaxed, that all it takes is five extra bits of information before the brain starts to give in to temptation.

This helps explain why, after a long day at the office, we’re more likely to indulge in a pint of ice cream, or eat one too many slices of leftover pizza. (In fact, one study by researchers at the University of Michigan found that just walking down a crowded city street was enough to reduce measures of self-control, as all the stimuli stressed out the cortex.) A tired brain, preoccupied with its problems, is going to struggle to resist what it wants, even when what it wants isn’t what we need.

There’s something unsettling about this scientific model of willpower. Most of us assume that self-control is largely a character issue, and that we would follow through on our New Year’s resolutions if only we had a bit more discipline. But this research suggests that willpower itself is inherently limited, and that our January promises fail in large part because the brain wasn’t built for success.

Everybody knows that the bicep has practical limitations: If we ask the muscle to hold too much, it will give out and drop everything on the floor. And just as our muscles get tired after a tough workout, and require a rest to recuperate, so does the poor prefrontal cortex need some time off.

In a 2002 experiment, led by Mark Muraven at the University at Albany, a group of male subjects was asked to not think about a white elephant for five minutes while writing down their thoughts. That turns out to be a rather difficult mental challenge, akin to staying focused on a tedious project at work. (A control group was given a few simple arithmetic problems to solve.) Then, Mr. Muraven had the subjects take a beer taste test, although he warned them that their next task involved driving a car. Sure enough, people in the white elephant group drank significantly more beer than people in the control group, which suggests that they had a harder time not indulging in alcohol.

There’s much more, including some great work by Roy Baumeister, et. al. on glucose, willpower and the self-defeating nature of dieting.

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Comments

  1. #1 AM
    December 28, 2009

    This seems to indicate that people who exert significant mental effort in their jobs (ex: PhD students, lawyers, etc) would have trouble exerting willpower in other areas of their life if it is so expendable. What solutions are there to this outside of removing the stimuli?

  2. #2 Maggie Wells
    December 29, 2009

    So this is the perfect explanation for why people with a lot of power,( i.e. politians and golf super-stars), and under a lot of stress, indulge in behavior society considers reckless and self-destructive.

  3. #3 Milt Lee
    December 29, 2009

    One way of actually increasing your ability to exercise self-control is meditation. The reason that it works is that by quieting the mind – consciously not thinking (say by focusing on one thing and returning your focus even when other stuff intrudes)- your mind gets stronger and your ability to make choices about what you are going to do increases. Meditation builds a new neural network for you to use however you want. Very cool.

  4. #4 Sharon Eden
    December 29, 2009

    Whoops, Jonah… notice how at least one of your commenters slips towards using this idea as an apologia for ‘reckless and self-destructive’ behaviours!

    As most experimental subjects are university students the extrapolation to other sectors of the population gives rise to doubt. OK we’re all human… ‘just’ for some of us. And there could of course be influential variables not taken into account in these experiments.

    While neuro-physiological functioning is a factor in all human behaviour, the above seems to me simplistic given the complexity of what I know of as ‘will power’ in this human being’s behaviour.

    Interesting stuff… thank you!

  5. #5 Sophia
    December 31, 2009

    A work-around to the limitations of willpower is to make something (doing it or avoiding it as the case may be) important to our identity. If necessary form a new identity in order to do this.

    For example, a tired Jewish person might cheat on their diet by eating some ice cream but it is unlikely they’d chow down on a bacon burger. Avoiding pork is part of their identity and so it requires little willpower to maintain this goal.

  6. #6 Life Lessons
    January 1, 2010

    Very nice point here. It’s better to deal with self development with scientific principles in the mix.

  7. #7 Beth
    January 1, 2010

    But what about habits that are intertwined such as drinking and smoking cigarettes? Research shows that a higher success rate for quitting those two at the same time (perhaps because one habit triggers the other). I think the research you cite is more supportive of the old HALT adage used in 12 step programs, which acknowledges that willpower fades whenever we become too Hungry, Angry, Lonely or Tired.

  8. #8 dsmccoy
    January 1, 2010

    Remember this is a statistical tendency not an absolute. Cognitive load doesn’t make willpower go away, it just makes it harder to sustain.
    The quote above says the subjects were “nearly twice as likely”, but the actual percentages can be found in a 2008 Frontal Cortex mention of the same research:

    http://scienceblogs.com/cortex/2008/03/glucose_selfcontrol_and_the_pr_1.php

    “Fifty-nine percent of people trying to remember seven digits chose the cake, compared to only 37 percent of the two digit subjects.”

    One way of reading that would be that 41% of the people chose fruit salad no matter what, 37% always chose the cake, leaving a mere 22% who made a different choice if loaded with an extra five digits worth of cognitive load. A very significant effect indeed, but not exactly determinism, and far from a sufficient excuse for randy politicians.

    I only have one minor nit to pick.

    “… all it takes is five extra bits of information …”

    I’m fine with the casual usage of the word “bit”, but this particular case is somewhat unfortunate since the text happens to be referring information. “Bit” has a precise meaning as a measure of information, and, in information science, a decimal digit requires more than one “bit” of information. Extra “digits”, “pieces”, “items”, or some other word would avoid confusing the casual definition of “bit” with its more precise definition as a measure of information.

  9. #9 Ray in Seattle
    January 2, 2010

    Sophia, You suggest that one can modify their behavior by making it part of their identity. I fully agree. But, I don’t think you appreciate how difficult that can be. Identity is developed early in life and becomes more solidified with age, with new layers cementing the earlier ones in place.

    In most cases a permanent change, not just feeling temporarily uncomfortable with one’s self image, requires a life-changing emotionally traumatic event, like a spouse dying for example or a severe bout of depression that utterly destroys one’s self image. Such events can be very painful.

    Identity is all our beliefs about who we are backed by the strongest emotions we possess – everything we’ve learned about how to survive and protect our well-being. Those beliefs form our road map for meeting life’s challenges. We’ll nurture it and go to great lengths to defend it from threats to change it.

    This idea transfers directly to other areas like the ME conflict. One reason that a negotiated solution based on dialog between Israel and its enemies is so elusive is that Palestinain governments have spent decades creating a particular identity in the minds of its people that requires the violent rejection of Israel and Jews from all of the ME. There is no part of that identity that calls for tolerance on that question – or even that sees ethnic tolerance toward any non-Muslim ethnicity as worthwhile. For most Palestinians being Palestinian simply means being a person who violently rejects the existence of Israel.

    It will take several generations of reasonable leadership that values peaceful coexistence working to create the opposite identity in Palestinians’ minds. That leadership must first have a personal identity that sees peace with Israe, even peace with anyone, as worthwhile. Sadly, because of the power of identity, such a radical process has not even been contemplated.

    And there you have identity, the psychological lock that assures that war and suffering will continue in that region into the foreseeable future.

  10. #10 Phil
    January 3, 2010

    I wonder if the administrators of the number memorization experiment established ahead of time that each subject regarded choosing between cake and fruit salad as a matter of making the right choice, rather than a simple matter of personal preference at a particular time. For example, I might choose the cake because I know that fruit salad is easier to prepare, and for the sake of variety decide to go with the item that I’m less likely to find the time to prepare myself.

  11. #11 Marena
    February 10, 2010

    Sophia and Ray in Seattle,

    Sophia is right on track when she says will power increases when a desired behavior is part of who a person thinks they are.

    However it is not necessary to form a new identity. Rather it is necessary to add another characteristic to the person’s identity. That characteristic must also be congruent with all the other beliefs the person holds about themselves or it will be dismissed or only become active under special conditions.

    We indeed go to great lengths to defend our identities and yet a person who wants to change can do so quickly and easily. NLP (Neuro-Linguistic Programming) is the easiest way to make identity changes. I’ve also seen energy work make changes in a person’s identity. Change can happen in an instant and need not be painful or a struggle.

  12. #12 Visualize
    April 14, 2010

    This was a great article, we try to do the same thing in sports when we are correcting skills we just correct one at a time, because it is impossible to correct them all at once, very insightful considering willpower.

  13. #13 deborah
    June 28, 2010

    Sophia, right on. My example has to do with becoming a vegetarian and then a vegan. I stopped eating meat 9 years ago for ethical reasons and was surprised at how effortless it was. I didn’t have to exercise willpower as I thought I would. Then 5 years ago I began to try to go vegan. Having been annoyed at those who ate fish but still said they were vegetarian, I was careful to tell people only that I was “trying to eat vegan”. It went on for months and I would still have cheese a couple times a week. Then at one point, I just started telling people that I was a vegan. It was a lie at the time, but within about a month, it was true. it was not worth the cognitive dissonance.