The New York Times has an opinion piece by Sandra Aamodt and Sam Wang, Tighten Your Belt, Strengthen Your Mind, on the implications of new research on ‘willpower.’ Daniel already noted this research in his post, Glucose, Self Control and Evolution, and linked to the original research paper, Self-Control Relies on Glucose as a Limited Energy Source: Willpower Is More Than a Metaphor.

The New York Times‘ piece discusses the possibility that spending discipline necessitated by economic hard times might lead to less ‘willpower’ when confronting weight control issues. The authors write:

The brain has a limited capacity for self-regulation, so exerting willpower in one area often leads to backsliding in others. The good news, however, is that practice increases willpower capacity, so that in the long run, buying less now may improve our ability to achieve future goals — like losing those 10 pounds we gained when we weren’t out shopping.

Specifically, the research team ‘found that people who successfully accomplish one task requiring self-control are less persistent on a second, seemingly unrelated task.’ In one study, subjects were either given radishes or freshly baked chocolate chip cookies before doing a puzzle (how did they get human ethics clearance for the cookies?!). The folks who ate the radishes lasted longer and were more persistent in experimental tasks than the cookie eaters, or those who were allowed to pass on the radish appetizer.

Daniel’s earlier post has links to several different discussions of the research article and briefly discusses some of the implications for dieting. I’ll let him do the talking (from the earlier post): The research

has implications for our understanding of brain evolution and for social problems like obesity and addiction. Focusing attention and using one part of your brain against another part, that takes significant energy. The brain is already our most energy-intensive organ, so adding the demands of “self control” on top of that is likely to have presented some adaptive issues in the past. Put differently, it’s unlikely to expect that we’ve evolved to be able to maintain self control over extremely long periods of time (say, months), simply because such problems rarely presented themselves in the past (there were few adaptive benefits) and because the energetic costs of doing so would have been quite high.

As Daniel discusses, our cultural ideals may not coincide with how difficult it really is to maintain self control, pitting one part of the brain against others. (You can also see his interesting discussion of Hans-Rudolf Berthoud’s theories about the relation between the environment and our brain around appetite at the end of the post, Obesity: Mortality, Activity and More.)

But it’s not just ‘acts of will,’ like ‘resisting food or drink, suppressing emotional responses, restraining aggressive or sexual impulses, taking exams and trying to impress someone,’ that make it harder to stick with puzzles or concentrate; we also do more poorly when we are physically tired from a strenuous task or from lack of sleep.

According to Aamodt and Wang, we’ve discovered what limits ‘willpower’: it’s blood sugar.

Exerting self-control lowers blood sugar, which reduces the capacity for further self-control. People who drink a glass of lemonade between completing one task requiring self-control and beginning a second one perform equally well on both tasks, while people who drink sugarless diet lemonade make more errors on the second task than on the first. Foods that persistently elevate blood sugar, like those containing protein or complex carbohydrates, might enhance willpower for longer periods.

So you have a limited supply of ‘willpower’ until you get more lemonade. Aamodt and Wang go on to discuss a whole range of scenarios in which a person’s limited stock of on-board ‘willpower’ might be tested (unless they’ve got a thermos of lemonade stashed somewhere): the dangers of window shopping before you go to a party where you’ll have to resist the pressure to drink too much, and conserving willpower for studying instead of using it to clean house.

But don’t worry too much about the ‘willpower’ tradeoffs because you can train it. A whole host of programs that exercise ‘willpower’ have collateral effects on activities that they don’t train:

In psychological studies, even something as simple as using your nondominant hand to brush your teeth for two weeks can increase willpower capacity. People who stick to an exercise program for two months report reducing their impulsive spending, junk food intake, alcohol use and smoking. They also study more, watch less television and do more housework. Other forms of willpower training, like money-management classes, work as well.

I wish blogging regularly were one of those ‘willpower’ increasing activities.

The last two paragraphs of the NYT column deserve to be quoted in full:

No one knows why willpower can grow with practice but it must reflect some biological change in the brain. Perhaps neurons in the frontal cortex, which is responsible for planning behavior, or in the anterior cingulate cortex, which is associated with cognitive control, use blood sugar more efficiently after repeated challenges. Or maybe one of the chemical messengers that neurons use to communicate with one another is produced in larger quantities after it has been used up repeatedly, thereby improving the brain’s willpower capacity.

Whatever the explanation, consistently doing any activity that requires self-control seems to increase willpower — and the ability to resist impulses and delay gratification is highly associated with success in life.

Okay, so wait a minute, ‘willpower’ is affected by blood sugar, and we’re pretty sure that increases in willpower are linked to some change in the brain, but we really have no idea what we’re talking about. It could be any one of several radically different mechanisms, or something we haven’t thought of at all.

I don’t want to be overly dismissive because I do think that behavioral research, like the psychology experiments being discussed, are valid on their own merits and point to interesting potential for neuroimaging studies (like on what area of the brains might be especially involved in acts of ‘willpower’). In fact, a fair bit of what we’re doing as neuroanthropology is exactly this sort of theoretical triangulation, taking data from behavioral observations, individuals’ testimony, and brain imaging — sometimes on different tasks or phenomena — and trying to draw some conclusions in spite of the leaps that must be made between the diverse data. So I have a lot of sympathy, on the one hand, for the attempt to think about what might be involved in ‘willpower,’ using different types of data and making some lengthy theoretical leaps when required.

However, we really don’t know much more from reading this article than we already could deduce from American folk ideas about ‘willpower.’ ‘Willpower’ is limited, so don’t tempt yourself too much; good training — like enlisting the kid in the Army or doing exercise for two months — will increase your ‘willpower.’ But I’m still not convinced that we even have a thing in the brain called ‘willpower’ (that’s why I keep putting it in quotes). Like the ‘tightening the belt’ in the mind of my admittedly tongue-in-cheek title, I’m not sure that ‘willpower’ is more than a metaphor, albeit an interesting one and one based in some regularities of experience. (Believing that the concept depends upon some observable regularity, feature, or pattern of experience and is not just a cultural creation is what makes my tendencies in cultural anthropology phenomenological rather than symbolic or hermeneutic, for our anthropologist readers.)

The original article insists that ‘willpower is more than a metaphor,’ and in some sense, sure, I can accept that. Acts of ‘will’ require blood sugar. No problem. Low blood sugar makes all sorts of mental tasks more difficult. But that still doesn’t easily settle the question of what ‘the will’ is and whether we have ‘a will.’ It just demonstrates that some acts of executive brain control get more difficult with less blood sugar, even if the brain itself has depleted the body’s stores (and we know that the brain is an energy hog in the body).

Now one issue I have with ‘willpower’ is the lack of specificity about the experimental stimuli. Basically, the Aamodt and Wang article has lumped together things that are significantly different. In the radish-cookie experiment, for example, the radish eaters didn’t have to resist eating the cookies; they just weren’t offered to them in the first place. Maybe radishes are just lousy brain food or giving people radishes as the first step in an experiment makes them want to go brush their teeth or convinces them that they’re not too into you as a researcher. And I’m not sure that ‘taking exams or trying to impress someone’ are acts of ‘willpower’ either. And sleep, well, that’s a whole other set of issues.

In other words, IF you group every experimental manipulation that causes performance on puzzles and concentration tasks together and label them all ‘expenditures of willpower,’ well then you get pretty clear evidence that using the will makes it difficult to do later tasks. But what you’ve really got evidence for is a whole list of tasks that make subsequent tasks more difficult, some of which involve stress, create physical fatigue, require a lot of concentration, or involve radishes and cookies.

I suspect that this thing Westerners call ‘willpower,’ especially if it demonstrated by all these experiments (some of which I would not label as ‘acts of will’), is various forms of executive control. For example, getting myself to exercise might require very different motivational mechanisms than avoiding an extra drink at a party. And both of these are very different processes, likely, than concentrating on puzzles or a videotape, both tasks used in the experiments. But I can imagine that, if we continue to use the Western concept of ‘willpower,’ we’re likely to have some sterile debates because we can be talking past each other. For example, the ‘willpower’ involved in dealing with pain is likely quite different than that involved in circling letters on a page of text, losing weight, or stopping oneself from lighting up a cigarette.

‘Willpower’ is, however, a phenomenologically consistent term. It clearly points to some characteristic of experience that is regular enough that the term makes some kind of sense to the people who use it, disclosing a quality of our experience. It’s possible that this quality is the actual effort required by different forms of executive control in the brian, or of different forms of auto-inhibition or social resistance. In that case, there may be a whole range of mechanisms that get involved BUT the shared quality of them — the thing that makes the term ‘willpower’ coherent — is the sense of effort, which might in fact be linked to something like use of blood sugar. In other words, ‘willpower’ might not be the action of a mental ‘will’ module but the sense of excessive energy being used by mental efforts that comes from a variety of acts. It would be interesting, for example, to learn if all ‘acts of will’ involve drops in blood sugar or are affected by them. I suspect that most would involve these drops and would become more difficult, but perhaps not to the same degree.

And some acts that we think of as related to ‘willpower’ might not have this sort of blood sugar mechanism involved. In this case, it would be more interesting to an anthropologist to ask why they get labeled ‘willpower’ by ‘natives,’ rather than just try to argue against the validity of the term, ‘willpower.’

Reference
Matthew T. Gailliot, Roy F. Baumeister, C. Nathan DeWall, Jon K. Maner, E. Ashby Plant, Dianne M. Tice, Lauren E. Brewer, and Brandon J. Schmeichel. 2007. Self-control relies on glucose as a limited energy source: willpower is more than a metaphor. Journal of Personality and Social Psychology 92(2): 325-36. (pdf, abstract)