Cognitive Daily

Greta has a jar of candy in her office, and she eats exactly one piece of candy per day (as well as offering it to her students whenever they visit). By contrast, if I have candy within 50 yards of my office, it will disappear within a day or two at the most (which is why I don’t keep candy in my office!). Why can Greta resist temptation while I cannot? A new study suggests that part of the reason may have to do with heart rate.

The Science Daily headline, “Why We Give In To Temptation,” is a little misleading. The research doesn’t show why I give into temptation while Greta does not; it simply demonstrates some key physiological differences between people who do and don’t have strong will power:

A measure of cardiac regulation called “heart rate variability” (HRV) appears to be linked to self regulation.

The researchers conducted a two-part study in order to test their hypothesis. In the first, participants were instructed to fast for three hours in order to take part in what they believed was a “physiology of food preference” experiment. Participants’ HRV was monitored while they were presented with a tray of cookies, candy and….carrots. Temptation, in this case, was indicated by giving into the tastier but decidedly less healthy snack of cookies and candy.

HRV as it turns out was considerably higher when people were working to resist temptation (eating carrots rather than cookies and chocolate) than when they were not, suggesting that HRV was mirroring the self regulation taking place.

Participants with higher HRV were also more likely to persist at a difficult (actually impossible) puzzle. But does high HRV cause people to have better self regulation? The study doesn’t show that. Perhaps high HRV and self-regulation are both caused by some other factor — the real root of self control. But it’s also possible that we can all get more will power just by taking a pill to increase our HRV.


  1. #1 Liz B
    March 23, 2007

    This is very timely, now that Girl Scout cookies are in circulation. I’ve already failed spectacularly to resist a box of Thin Mints.

  2. #2 Roy Huggins
    March 23, 2007

    So does this mean that a person who persists at difficult tasks well might be likely to suffer anxiety or develop heart disease? Or am I reading too much into the HRV measure?

    And PS: No one can fault you for the Thin Mints, Liz. I think the study should have amended that while self-regulation may be affected by HRV, no one can resist Thin Mints. Even if they don’t even have a heart. 🙂

  3. #3 Natalie
    March 23, 2007

    While I am generally very good at resisting temptation and only eating my personally allotted amount of cookies and candies for the day, certain things are just too tempting. For me it’s not Thin Mints – it’s Robin’s eggs that I will eat until my mouth hurts from the skins. Mmmm

  4. #4 argotnaut
    March 23, 2007

    Only one box, Liz?

  5. #5 mike-2
    March 23, 2007

    This is great news! Now we only need to find out what HRV actually is, we’ll be set.

  6. #6 Liz B
    March 23, 2007

    Roy, I think you’re on to a new marketing slogan: Thin Mints — Even the heartless can’t resist them.

    As for the number of boxes … it was only one. On this most recent occasion, anyway.

  7. #7 aaron
    March 23, 2007

    test subjects would have to be controlled for their cultural background. certain societies take self-control (especially when it comes to food) more seriously than others. for instance, i have an asian friend who would feel obliged to fall on his sword if he gave into the temptation of the cookies or the candy.

  8. #8 Brandon
    March 23, 2007

    Isn’t lower HRV also partly linked to negative emotions like anxiety or depression? Or am I misremembering that?

  9. #9 pdf23ds
    March 23, 2007

    Exercising raises HRV. Exercise for self-control! That’s a bit of chicken-and-egg problem.

  10. #10 Alvaro
    March 24, 2007

    As far as I know, there is no magic pill to increase HRV. But there are biofeedback based systems that allow us to see our HRV in real-time AND train ourselves to improve our HRV quality.

    Brandon: yes, HRV is a good indicator for anxiety and stress, on the one end, or being in the physiological “Zone”, in the other.

    Our discussion on a recent paper (Appelhans BM, Luecken LJ. Heart Rate Variability as an Index of Regulated Emotional Responding. Review of General Psychology. 2006;10:229-240) is below:

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