Sweet Science: Squirting Milkshakes?

By John M Grohol PsyD
October 18, 2008

A study was published yesterday in Science that demonstrated an association between obese individuals and a particular gene version that has fewer dopamine receptors:

Eating can temporarily boost dopamine levels. Previous brain scans have suggested that the obese have fewer dopamine receptors in their brains than lean people. And a particular gene version, called Taq1A1, is linked to fewer dopamine receptors.

What caught my eye wasn’t that this was another fMRI study, but that neuroscientists are becoming increasingly imaginative in ways to get around the fact that an fMRI scan is not a natural thing for anyone to do.

fMRIs only work when you’re motionless. Movement screws up the data, so the more you move, the less useful the data is to the researchers. So as researchers seek to study more and more human behaviors, they have to become more and more innovative in having people engage in normal everyday activities while in a small cylindrical tube in a hospital.

In this study, researchers needed to get the participants to drink a milkshake. You know, that delicious frozen concoction you slurp slowly through a big straw. Like most eating or drinking, it’s a behavior that involves multiple senses — not simply the act of digesting some tasty liquid into one’s stomach.

But that’s what neuroscientists boil it down to for their research. In the study, the researchers squirted the milkshake into participants’ mouths to simulate the effect of a milkshake. Really?

I’m sorry, but I don’t see how you can squirt a milkshake anywhere (at least a properly made one). And how we can engage in research like this and pretend it approaches anything close to normal human behavior. I can’t wait until scientists — in the name of science, of course — find a way to have two people have intercourse in one of these things and measure their brains. (You know it’s only a matter of time.) Will they have to put one of their heads in a neurosurgery skull clamp to keep it from moving?

Despite the completely artificial situation and what must’ve been an icky-tasting milkshake, the researchers still found the positive data they were looking for. The researchers concluded that when the brain doesn’t sense enough gratification from food, people may overeat to compensate.

Suggesting that perhaps you can do active-behavior research in an fMRI machine after all.

Read the full article: Study ties weight gain link to taste of foods

Read the Science article: Relation Between Obesity and Blunted Striatal Response to Food Is Moderated by TaqIA A1 Allele

Dr. John Grohol is the CEO and founder of Psych Central. He has been writing about online behavior, mental health and psychology issues, and the intersection of technology and psychology since 1992.