Here’s another story from my Just Because It’s In The Newspaper Doesn’t Mean You Should Believe It files.

The New York Times Magazine ran a piece last week about some new—though not exactly groundbreaking—social psychology research on willpower. Seems that people have more trouble making decisions and act more rashly when they’re tired or hungry. Any parent of a cranky toddler could tell you that. But, wait, there’s more.

This so-called decision fatigue, according to one economist who studied (I am not making this up) soap-buying decisions among poverty-stricken villagers in rural India, explains why the poor remain trapped by their financial circumstances. He believes diminished willpower causes crime, alcoholism, poor school performance, and other problems that maintain the cycle of poverty.

“Shopping can be especially tiring for the poor, who have to struggle continually with trade-offs.” That’s why, he says, the economically disadvantaged eat junk food at the mall; they can’t resist the allure of the food court because all the trade-offs deplete their willpower.

The author goes on to talk about the mitigating effect of sugary foods on “ego depletion” (the draining of mental energy used for self-control). And then he makes the following statement: “The ego-depletion effect was even demonstrated with dogs . . .After obeying sit and stay commands for 10 minutes, the dogs performed worse on self-control tests . . .But a dose of glucose restored their willpower.”

Whoa! There’s so much wrong here I hardly know where to begin.

Problem 1: How do you measure willpower?

In one experiment, self-control was measured by how long the subjects could hold their hands in ice water before giving into the urge to pull them out; in the Indian study, it was tested by seeing how long the subjects could squeeze a hand grip. What about individual differences in cold tolerance and grip strength? And couldn’t the poorer Indians have weakened more quickly because of malnutrition rather than lack of willpower?

Problem 2: Correlation does not equal causation.

Any Statistics 101 student knows this cardinal rule. Impulse-control problems may be more prevalent in poorer populations, but that doesn’t mean poverty causes weak willpower. Other factors could just as easily enter into the equation—fatigue resulting from having to perform a physically taxing job, say, or the draw of money-making criminal activities for a person desperate to find a way out of bleak circumstances. And, if the sheer volume of decisions depletes willpower, what about the CEO who constantly has to make decisions to run a company?

Problem 3: Generalizing about human cognition from animal studies is silly.

To say that dogs suffer from “ego” depletion after exercises in sustained self-control is just plain wrong. The concept of ego implies a capacity for self-awareness, which dogs lack. If they look in a mirror, they don’t recognize the image staring back at them as themselves. This has been tested in many different species by painting a dot on an animal’s forehead and presenting it with its reflection in a mirror. Elephants investigate the spot with their trunks; gorillas poke at it; and human children after the age of eighteen months or so notice it. But dogs don’t. They have no sense of self and, hence by definition, no ego.

In all fairness, I haven’t read the original studies, so I don’t know if these problems are in the research or in the way the reporter interpreted it. Still, the average newspaper reader wouldn’t go back to the original sources, either. Most of us take what we read or hear in the news at face value.

It’s easy to confuse fact with fiction if you don’t question the evidence.