Having low blood glucose means you are more likely to stick pins in a voodoo doll that represents your spouse, a new study suggests.
And you are more likely to blast your spouse with a loud unpleasant noise – given the chance, finds a study published this week in the Proceedings of the National Academy of Sciences.
The findings could point to a previously unrecognised contribution to aggression between married couples, says lead author Dr Brad Bushman, a professor of communication and psychology at Ohio State University in Columbus.
Preventing aggressive behaviour relies on self control, which is governed by our pre-frontal cortex, says Bushman. Self control requires energy, part of which comes from glucose.
“It’s widely accepted that glucose boosts self control,” says Bushman. On the contrary, when our brain doesn’t get enough glucose, we can get cranky – something most of us can attest to from personal experience.
Voodoo doll experiment
Bushman and colleagues previously showed that glucose was linked to control of anger in a short-term lab experiment involving interactions between strangers. But everyone knows we are most likely to snap at people we’re closest to. So in their latest study, Bushman and colleagues studied interactions between married couples in their own home, over a much longer time frame.
For 21 days, 107 couples had their blood glucose tested daily and just before each glucose test they got the opportunity to express aggression towards their spouse.
They were given a voodoo doll that represented their spouse and told they could stick up to 51 pins in the doll, depending on how angry they felt with their other half.
“People with lower glucose stabbed more pins in the doll than people with higher glucose,” says Bushman. People whose glucose levels were in the lowest 25 per cent put over twice as many pins in the doll as people whose glucose levels were in the top 25 per cent.