Vicious cycle effects should undermine belief in free will
A follow-up on free will, feedback loops, and why effort isn't the clean lever we think it is
Last time I argued that a lot of what we praise and blame people for, their grades, their income, their waistlines, traces back to things they never chose: their genes, their birth date, the zip code they grew up in. Here's the part that makes the free-will problem worse. Disadvantages don't sit still. They compound. The state you're in starts producing the very thing that keeps you in it.
Take testosterone and body fat. Endocrinologists even have a name for the loop: the hypogonadal–obesity cycle. Fat tissue is loaded with aromatase, an enzyme that converts testosterone into estrogen, so the more fat you carry the more testosterone you lose. Low testosterone then does its own damage. It parks fat around the abdomen, eats into muscle, and saps the energy and drive you'd need to train it off. More fat, less testosterone, less muscle, less will, more fat. Round and round.
Figure 1 in this paper) has a crazy scatterplot showing total testosterone increase rising with percentage of body weight lost across nine studies - with large effect sizes.
The figure shows the hopeful half. Lose weight and testosterone climbs back, roughly in step with how much you shed. The men at the top right, who lost about a third of their body weight through bariatric surgery, got the biggest rebound. So the loop breaks. But look at what breaking it asks of you: row hard upstream against a current your own body is generating, using the energy that current is busy draining.
Poverty has the same shape. In a 2013 study, researchers tested the same Indian sugarcane farmers twice, once before harvest when they were broke and once after when they'd been paid. The same men scored noticeably higher after harvest, on the order of nine or ten IQ points, a gap comparable to a sleepless night. The reasoning is that worrying about money is itself cognitively expensive: it eats the mental bandwidth you'd otherwise spend on planning and self-control. There's the trap. Poverty taxes the exact faculty you need to climb out of it. (In fairness, the flashier lab versions of this "scarcity" effect have taken a beating in replication fights, though the harvest result is the sturdier leg of the story.)
This is why a feedback loop is nastier for free will than a bad starting hand. A bad start is a one-time disadvantage you might, with effort, overcome. A vicious cycle goes after the effort itself. "Just try harder" assumes the trying is sitting there available, when the whole problem is that your situation has quietly confiscated it.
Which is roughly where I landed last time. For policy, plan around the loops and break them structurally, rather than scolding people for failing to out-will their own biochemistry or bank balance. In person, by all means keep telling your kid to study. Just don't confuse the pep talk for a theory of how the world works.