HUNGRY
HOW A SEXY NARRATIVE CAN MAKE US FORGET THAT CORRELATION DOES NOT EQUAL CAUSATION
Ego depletion is the hypothesis that willpower and self-control are limited resources that diminish with use, like when we exercise or resist a plate of cookies or do hard math problems.
The original result that kicked off the ego-depletion hypothesis came from Roy Baumeister, et. al. in 1998 showing that
people who are forced to resist a plate of cookies give up on solving hard puzzles more quickly.
Other results followed including a
famous study showing that willpower could be replenished with sugary drinks.
It’s a sexy narrative.
Break down and eat a pint of ice cream at the end of the day? Ego Depletion!
Eat that huge muffin after working out? Ego Depletion!
It turns out, though, that many of the more famous ego depletion studies
don’t replicate.
One of the more well-publicized studies found that judges issued harsher sentences right before lunch.
The interpretation?
“
Judges’ Rulings Are Harsher When They Are Hungrier“ declared just one headline describing the findings.
Shai Danziger and colleagues took data from 1,112 parole decisions by Israeli judges. They found “the likelihood of a favorable ruling is greater at the very beginning of the work day or after a food break than later in the sequence of cases.”
What followed was the prescriptive advice that simply taking a food break “may lead judges to rule differently in cases with similar legal characteristics.”
That fit neatly with the then-hot concept of ego depletion.
But
a subsequent paper by Keren Weinshall-Margel and John Shapard revealed a much more mundane explanation for the harsher sentencing: prisoners without lawyers receive parole at a much lower rate.
And, guess what?
Defendants without representation have their hearings scheduled at the end of sessions, before breaks.
Like lunch breaks.
No one is questioning the data collection of the original research. The correlation was based on facts (the dispositions and the time of day of the dispositions) ascertainable with a high degree of certainty.
The conclusion of ego depletion (in this case the judges being hungry), however, was not a fact. It was an inference of what caused the correlation between time of day and how the judges granted or denied parole.
Facts and truth aren’t the same thing.