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When I was a kid, my dad did something on family vacations that perplexes me to this day: He ran. Every day, at least four or five miles, rising before the sun and before anyone else was awake. He wasn’t training for anything. He wasn’t trying to lose weight. There was no specific goal, no endpoint, no particular reason he couldn’t take the week off while in the greater Disney World metropolitan area, which, in July, is hotter than the surface of the sun. He was just running, like he had basically every day since time immemorial. My dad will turn 75 next week, and whenever you’re reading this, he has probably already been out for a run today.

My dad didn’t always run. He started a few years before I was born. One day he wasn’t a jogger, and the next day he was, even if he didn’t know at the time that the change was indeed permanent. When I asked him why he started all those years ago, there was no great motivator, no epiphany. "It was the cool thing to do at the time for people like me," he said of the 1980s fitness boom. Now, when my dad doesn’t run, "I feel like I’ve lost something," he told me.

For a lot of people, this is, without exaggeration, the dream: You decide you’d like to start doing something, you get past the initial phase of this new activity being hard and bad and a huge bummer, and then you do that thing for 40 years. It’s a deceptively simple fantasy—and, so often, an impossible one. Right now, I work out once or twice a week, which is less than I’d like to. I’ve tried to form various exercise habits over the years—I bought the equipment, I made a plan, I got out there and did it—and never quite reached the automatic stage, even though I observed it at close range for my entire childhood. My experience is extremely common among people who want to change how they do all kinds of things: to waste less money, to floss, to quit smoking, to drink less, to learn a new language. And it’s a salient dynamic at the beginning of a new year, resolution or not. New beginnings are seductive, and so is our own capacity for change. You tell yourself that, this time, you’re really going to do God-knows-what differently, but all too soon you’re reminded that forever is a pretty long time to keep it up.

Stories like my dad’s often serve as pop-psychological proof that you, too, could become a runner, if you really wanted to. But we all want things—human longing knows no bounds—and plenty of people do genuinely throw themselves into trying something new, without much success at converting those behaviors into lasting habits. If some people can just get up one day and decide to behave differently for the rest of their life, why do most people fail at it again and again?

The conventional wisdom on changing habits goes something like this: You can change if you really want to. Americans especially tend to see ourselves and one another as individuals with identical reservoirs of willpower, which some people choose to use and others do not. If you can’t figure out how to get up at 4:30 in the morning to make sure you get five miles in before commuting to work every day, which my dad somehow did for 30 years, you’re not trying hard enough, or you don’t want it badly enough, or you’re not motivated enough. Try harder.

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Now, as anyone who has ever tried anything might suspect, it sure seems like that idea might be bullshit. Or at least, many researchers have concluded that it does not account for an enormous amount of observed human behavior, according to the psychologist Wendy Wood. In her book Good Habit, Bad Habit, she explains that for the latter half of the 20th century, psychological scholarship more or less affirmed its righteousness. Attitude leads behavior, the theory went, and the circumstances in which you exist aren’t that important to the choices you make. Individuals do certain things and not others mostly because of their own conscious decisions; your fate is largely in your own hands. You can see how this logic permeated culture: The self-help and diet industries boomed, the government slashed the social safety net’s tires, the 1970s became the Me Decade.

In the past 20 years, the field’s tune has begun to change. According to Michael Inzlicht, a social psychologist at the University of Toronto, the most recent research suggests that conscious decision making plays a much more minor role in people’s actions than previously thought, and long-term behavior patterns largely aren’t created by stringing together a series of conscious choices. How people use the phrase self-control, he told me, tends to conflate two different things: a largely immutable element of someone’s personality (a trait) and a way that someone chooses to behave at a particular time (a state). Trait self-control varies from person to person, he said, and the amount you get is probably determined by some combination of heredity, culture, and environment. A person who has high trait self-control might be preternaturally punctual, whereas the timeliness track record of an average person—even one constantly trying hard to make it to things on time—might be more subject to the whims of circumstance.

The key distinction here, Inzlicht told me, is that a person who appears highly self-controlled to others—who is displaying a high level of trait self-control—probably isn’t exercising their behavioral self-control as much as you do. "People who have high trait self-control, they don’t actually engage in more restraint of their behavior and thoughts and emotions in the moment," he said. Instead, they just aren’t tempted or distracted or diverted from their purpose as often or as effectively as the rest of us. For the small number of people at the far end of the trait spectrum, the things that others have to exercise self-control to resist every single time—sleeping in, skipping the gym, making impulsive purchases, having a cigarette even though they’re trying to quit—often just don’t get recognized as viable options in the same way that they do by the rest of us. This doesn’t mean it’s always easy for these people to sit down to study or to get out the door to exercise, but broadly speaking, they’re less readily pulled away from their plans by the siren song of novelty or opportunity, so they don’t have to rely on their active sense of restraint, with its far less reliable results, as frequently.

My father, I suspect, is one of the people at the far end of this personality continuum. It’s not just the running: He smoked for more than 20 years—back when everyone smoked, he would want me to stipulate—but he quit on his first try and never looked back. After he decided he liked running every morning, he added on an evening strength-training routine several days a week, and has stuck to the two-a-days for decades. He always eats breakfast, and the meal—a big bowl of Raisin Bran and a buttered, toasted bagel for much of my childhood—goes unchanged for years at a time. He is always reading a book, often about history, and has probably consumed hundreds of thousands of pages of dry descriptions of obscure military battles in my lifetime, for fun. He is what happens if you make the whole plane out of New Year’s resolutions.

Inzlicht described the evidence that any given person can increase their level of trait self-control to be more like my dad as "extremely weak," but said that researchers should nonetheless still keep looking for ways it might be possible. Having the inherent ability to more easily form good habits and jettison harmful ones is enormously beneficial—people who can do that tend to be healthier, happier, and more financially stable. My dad is an easygoing, curious, nonjudgmental guy, and a very good dad. He’s not constantly working against himself to do the "right" thing, or to do anything at all. This is just how he is. "I don’t get out in that lane, I don’t get out in this lane, I stay in my lane," he said, when I asked him about his routines. "These are the things that I like to do."

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According to Wood, the Good Habit, Bad Habit author, forming new long-term behavioral patterns is possible to some extent for most people, and it’s largely a function of learning to do something so automatically that you perform the task without having to consciously decide to do it, like brushing your teeth before you go to bed. She runs the University of Southern California’s Habit Lab, where she studies how and why people learn to change their behavior. She says that people who go to the gym a lot, for instance, don’t have to decide to go every time—they just sort of find themselves headed in that direction at the appropriate moment.

For those to whom habit-formation doesn’t come so naturally, the circumstances you’re in can make a big difference. Stability, for instance, is an enormous boon: Many people who leave work at the same time every day are able to rely on their routine as a cue to tell themselves that it’s time to go to the gym. If only half your workdays end when the gym is open, converting that choice to a habit can be much harder. Having money to buy the tools that make a new behavior easier or more rewarding is also enormously helpful, as is consistent access to the environs in which new tasks can best be performed. My dad started running on safe, low-traffic streets, which gave him the opportunity to realize that he really, really liked the rush of endorphins that is often called a runner’s high, which reinforced the creation of his new habit in ways that Wood has found to be crucial.

One study Wood described found that people who lived within four miles of a gym went much more frequently than people who lived farther away, even when the difference between the two groups was only a mile or two. Another study found that adding farm stands outside of schools and community centers in a low-income area of Austin, Texas, meant local residents ate more vegetables, even if nothing else was done to encourage people to change their dietary habits, or even to tell them the farm stands were there. "That’s part of the health advantage of higher-income folks," Wood told me. "They live in environments that are more conducive to exercise; they’re less likely to live in food deserts; they have access to restaurants beyond just fast food." For many people who make something out of their good intentions and healthy tendencies, those successes have been supported by policy choices that they had nothing to do with. To Wood, the implication is clear: If you want people to behave differently en masse, you’re going to have to change—to improve—the circumstances in which a lot of them live.

I do not mean to sound fatalistic here. It’s not that personal change or self-improvement is impossible—most people can change their habits and create new ones, according to Wood, if they set realistic goals and they’re able to create cues and rewards that effectively encourage repetition. Much of that involves tinkering with the circumstances of your existence that you can affect. For instance, I became a more frequent flosser by taking the package of floss out of my medicine cabinet and sitting it next to my toothbrush, where I could always see it. I used to procrastinate on washing dishes, but now I do them every day like clockwork, thanks to a Bluetooth speaker that I use to listen to podcasts while I stand at the sink. Having a clean kitchen, in turn, means I cook more—an activity I really enjoy—and resort to expensive takeout orders less frequently. I figured out what was stopping me from doing some of the things I knew I could do, and I tried to eliminate the obstacles I could control, to reasonable success. Figuring out how to do something a little less or a little more is likely to yield the best results for most people, even if it’s not going to turn you into a different human.

Before you do any of this, though, or before you decide you’ve failed, it’s probably worth making peace with who you are as a person. My irregular exercise habits don’t really bother me anymore, mostly because I do not take myself as seriously as I used to. I figure that I am who I am, give or take a reasonable capacity for marginal change. I have exercise equipment in my apartment that I could use more often, but I simply do not feel like it. I have never once felt like it, even if I have often wanted to be a person who does. What I can actually do for myself over the next year to make my life better probably will not include a spontaneous dedication to daily exercise. It may include more careful attention to, say, reading or cooking—things that I already love, and that are good for me. Before I left my parents’ house over the holidays, Dad made sure to pass on a few books he thought I’d enjoy. None of them is about war.