If you and your spouse are constantly fighting, there may be a cause that makes a little more sense than whether somebody remembered where the serving spoons go. One psychologist thinks it might have to do with blood sugar. But the weird part is how he arrived at that idea.
Psychologist Brad Bushman, with Ohio State University at Columbus, studies the role of blood sugar levels in behavior. A few years ago, he hypothesized that low glucose levels in the blood might be causing spouses to behave more "aggressively" toward each other. The question is, how do you measure the relationship between a person's blood glucose levels and anger levels directed at a spouse?
In Science, Gisela Telis writes:
[Bushman] and colleagues at the University of Kentucky and the University of North Carolina recruited 107 married couples and equipped them with blood glucose meters, voodoo dolls, and 51 pins to record their glucose and anger levels over time.
For 21 days, the couples used the meters to measure their glucose levels each morning before breakfast and each evening before bed. They also assessed how angry they were at their spouse at the end of each day, by recording how many of the 51 pins they stuck into their voodoo dolls just before bed when their partner wasn't looking. After 21 days, the couples were invited into the lab. There, they played a computer game that allowed them to blast their spouse with an unpleasant noise—a mixture of fingernails scratching a chalkboard, ambulance sirens, and dentist drills—as loudly and for as long as he or she wanted, as a proxy for their willingness to act aggressively and make their partner suffer.
What they found, according to Telis, is that "spouses with lower evening glucose levels showed more anger and aggression toward their partners." People who scored in the lowest 25th percentile of glucose levels stuck roughly twice as many pins in their voodoo dolls as those in the upper 25th percentile.
This seems like a really bizarre proxy for anger. First of all, as one expert noted in the Science article, it's hard to say what these glucose levels mean without knowing what caused them. For example, alcohol can lower glucose levels but also raise aggression levels too. But the study didn't ask the subjects what they had been eating and drinking. Second of all, is sticking pins in a doll or secretly desiring to blast somebody with noise really a good proxy for "anger"? It sounds more like a proxy for wanting somebody to suffer, which isn't quite the same thing.
Also, it would have been interesting to find out whether these urges to make the spouse suffer were related to things the spouse had done, or were simply part of an overall rise in aggression caused by blood sugar levels. Presumably glucose levels would affect one's outlook on everyone, not just a spouse.
If you'd like to try part of this experiment at home, here's the noise that subjects blasted at their partners. You'll have to supply the dolls and pins yourself.
Read the full scientific study in the Proceedings of the National Academy of Sciences
Doll image from the study provided by Brad Bushman