People's brain activity shows their political affiliation while buying food

People’s political affiliation can be shown in their brain activity when they carry out mundane chores such as buying food, a new study shows.

How the brain reacts to food purchasing decisions can be used to determine people’s political affiliation with almost 80 per cent accuracy, researchers have found.

Although buying eggs and milk can lack emotional potency and political content, understanding how the neural systems lead people to make indistinguishable choices may help to explain the broader mechanisms of partisanship.

The researchers behind this latest study measured the brain activity of adult US Republicans and Democrats via MRI while they made the food choices.

The two groups didn’t make significantly different decisions about food purchases, but the way their brains activated as they made decisions differed according to their party affiliation. Republicans showed greater neural activity than Democrats in specific regions of the brain, and Democrats had greater neural activity than Republicans in other regions.

The findings suggest that political orientation might be partially rooted in basic neurocognitive mechanisms that occur even when the choices are non-political. This may help to explain the broader mechanisms of partisanship.

What the researchers say: “You cannot tell whether someone is a Democrat or a Republican when you see them buy free-range eggs, but if you were to examine their brain activity, you would see that they are using different parts of their brains in that decision. The brain activity predicts the party, not the purchase,” the lead author explained

“We know from studies of twins that about 50% of your political ideology is biologically heritable and that data from your parents allows us to infer your political party with 69% accuracy,” the researchers added. “So, it is pretty amazing that just the signal from the brain while you’re buying eggs and milk enables us to correctly classify your political party about 80 per cent of the time.”

The fMRI scanner recorded activity in several areas of the brain including the ventromedial prefrontal cortex, which is associated with decision making.

“We can discern your likelihood of being in one party or another from how those brain regions react to what you are choosing even if the choices end up being exactly the same as someone in a different party. I think that is what is intriguing - we can’t tell if you’re a Democrat by the eggs you buy, but by the parts of the brain you use to buy the eggs,” the researchers continued. “We gave the subjects $50 but they were told that one of the products they selected would be given to them at the end of the study and its price would be deducted from their $50. So, they went home with either a jug of milk or a carton of eggs and whatever money they had left after the purchase.”

The researchers chose to use milk and eggs in the study because they wanted common grocery items that were indistinguishable by brand, as branding can make purchasing decisions more personal and changes the way we think about them.

“I would be amazed to find that the results do not hold up with other product choices - the parts of your brain that are active when buying a carton of eggs are active when other decisions are made, the lead author said.

My take: This research adds to a ton of recent research indicating that our political leanings are driven by our biology rather than our rationality.

We are programmed to be either “little liberals or little conservatives” as the song from Gilbert and Sullivan’s opera Iolanthe puts it. This genetic programming determines not just our political preferences, but also many factors in our decision-making including our risk tolerance.

We know from prior research that this genetic difference predisposes “liberals” and “conservatives” to shop in different ways. A number of studies have shown, for example, that people of a “liberal” mindset will more likely buy store-branded goods and search for bargains than “conservatives” who are more likely to stick to a brand. Buying the unbranded goods is seen by them as more of a risk.

Given all this, it is unsurprising that Democrats and Republicans use different parts of the brain to make commonplace decisions.