How to Change

Why do our best intentions so often derail when we try to change our habits—whether that means eating healthier, exercising more, or staying focused at work? In How to Change, behavioral scientist Katy Milkman argues that the real challenge isn't knowing what we want to change; it's learning how to overcome the specific psychological obstacles that stand in our way. Her research shows that there’s no one-size-fits-all solution: just as tennis coach Brad Gilbert helped Andre Agassi fix his game by tailoring his strategy to each opponent, you must craft a personalized approach to your own barriers.

Milkman’s central claim is simple but transformative: success comes from understanding your internal opponent—whether that’s impulsivity, procrastination, forgetfulness, laziness, lack of confidence, or pressure to conform—and then applying science-backed tactics designed specifically to counteract that adversary. She turns a complex body of psychological research into an engaging, actionable guide that feels like having a behavioral scientist as your personal coach.

Understanding the Personalized Path to Change

Just as Agassi’s career soared when he stopped forcing himself to play like everyone else and instead exploited what made him unique, Milkman shows that effective behavior change requires personal diagnosis. You don’t fail because change is impossible; you fail because you’re applying the wrong strategy to your particular obstacle. For instance, if you struggle with forgetfulness, a commitment contract won’t help—but cue-based planning might. If you’re lazy, setting clever defaults and habitual systems will outperform sheer willpower. This approach reframes personal transformation as an engineering challenge rather than a moral one.

The Seven Core Obstacles

Milkman divides the journey of change into seven psychological roadblocks: getting started, impulsivity, procrastination, forgetfulness, laziness, confidence, and conformity. Every chapter treats each obstacle as a separate opponent on the tennis court of life and presents empirically proven tactics to conquer it. For example, “Getting Started” examines the Fresh Start Effect—moments like New Year’s Day or birthdays when you feel capable of starting anew. “Impulsivity” teaches how to harness temptation through bundling pleasure with effort. “Procrastination” exposes the power of commitment devices, while “Confidence” shows how giving advice can boost self-belief instead of eroding it.

From Insight to Action

What makes Milkman’s work distinctive is its balance between academic rigor and practical accessibility. Drawing on hundreds of field experiments—from Google to the U.S. Air Force Academy and nonprofit organizations—she reveals how small interventions like timing reminders, setting defaults, or changing peer groups can yield enormous results. Her collaboration with psychologist Angela Duckworth at the Behavior Change for Good Initiative ensures every strategy rests on empirical data, not motivational slogans.

Why This Matters

Milkman emphasizes that personal change is not a sprint but the management of a chronic condition—one requiring continued attention. The obstacles to change are built into human nature, so the right science-based tools must become lifelong habits. Her goal is not just to motivate you but to help you design systems that make good behavior the path of least resistance. In this way, the book offers both hope and realism: lasting transformation is possible, but it demands that you engineer your environment and routines in line with how your brain actually works.

In the chapters that follow, you’ll learn how to harness fresh starts to begin anew, how to make healthy behaviors instantly gratifying, how to tackle procrastination with commitment devices, how to outsmart forgetfulness with cue-based planning, how to turn laziness into an asset through defaults and habits, how to bolster confidence by giving rather than receiving advice, and how to use social forces for good without falling prey to conformity. Together, these insights form a master plan for lasting behavior change—a guide for getting from where you are to where you want to be.

Milkman begins her roadmap with the question of timing: when is the best moment to start change? Through her collaboration with Prasad Setty at Google, she discovered what she calls the Fresh Start Effect—the psychological phenomenon that certain landmark moments make us feel like we’ve wiped the slate clean and can begin anew. Whether it’s New Year’s Day, the first day of spring, or even a birthday, these temporal landmarks help us distance ourselves from past failures and imagine ourselves as a ‘new me.’

Why Fresh Starts Work

Fresh starts operate through three psychological levers. First, they separate your past identity from your present self—you’re no longer the person who failed yesterday. Second, they boost optimism and reduce guilt, shifting the emotional terrain of change. Third, they help you zoom out from daily routines and see the bigger picture, making change feel meaningful. Ray Zahab’s story embodies this effect: after decades of unhealthy living, he quit smoking on New Year’s Eve 1999, framing January 1, 2000, as the dawn of a new century and the beginning of a new life.

Life Events as Fresh Starts

Milkman shows that we can harness not just calendar shifts but personal transitions: moving homes, starting a new job, or recovering from illness. These events disrupt routines and open mental space for change. Her former tennis coach, Bob Pass, used a heart valve infection as a catalyst to leave law and found a tennis academy. Likewise, disruptions like the London tube strike or transferring colleges can reset habits simply by altering our environments.

The Downside of Fresh Starts

Too much resetting, however, can sabotage success. Milkman and her student Hengchen Dai found that while fresh starts strengthen motivation after failure, they can also derail high performers. When Major League Baseball players were traded across leagues (creating a statistical fresh start), struggling athletes improved—but top performers declined, losing momentum when their records reset.

Using Fresh Starts Strategically

For companies, timing change matters just as much. Milkman’s postcard experiments with university employees showed that nudges to save for retirement were 20–30 percent more effective when timed to coincide with fresh starts like birthdays or springtime. Google even built a “moments engine” to prompt employees after promotions or relocations—times when people are primed to act differently.

Milkman concludes that if you’ve struggled to begin a change, wait for or create your own fresh start—a new year or a new chapter—and use it to claim momentum. But beware of losing progress when things are already going well. Fresh starts are powerful launchpads, but progress requires steady follow-through.

We all know what the right choice looks like—take the stairs, eat the salad, study for the exam—but we often choose immediate pleasure instead. Milkman identifies this as impulsivity, or ‘present bias,’ the universal tendency to overvalue instant gratification at the expense of long-term rewards. Her solution doesn't rely on suppressing temptation but on harnessing it.

Temptation Bundling

Milkman invented ‘temptation bundling’ during graduate school when she allowed herself to read thrillers only while exercising. The result was two wins: she devoured her favorite stories guilt-free and became a consistent gym-goer. Years later, her Wharton experiments proved its power. Participants given audio novels like The Hunger Games could listen only while working out; their attendance increased 55 percent compared to controls.

In a follow-up with Audible and 24 Hour Fitness, simply suggesting people pair workouts with audiobooks raised weekly exercise for 17 weeks—showing that even soft nudges work when pleasure and discipline intertwine.

Gamification: Turning Work Into Play

Another route to instant gratification is gamification—making effort feel like a game. Economist Jana Gallus’s Wikipedia experiment demonstrated this: volunteers who received symbolic ‘stars’ for contributions were 20 percent more likely to keep editing months later. However, as researchers Ethan Mollick and Nancy Rothbard found, imposed games can backfire if people don’t ‘buy in.’ The magic circle of play must be voluntary.

The Mary Poppins Principle

Milkman calls this the ‘Mary Poppins approach’: add a spoonful of sugar to make the medicine go down. Fun is not childish—it’s strategic engineering for human motivation. Google’s playful offices, Zappos’ virtual happy hours, and reward-based apps all embody the idea. If you can make healthy, productive actions pleasurable in the short term, you’ll stay consistent long enough for them to become habits.

By flipping the script and making gratification serve your long-term interests, you neutralize impulsivity. In short: don’t fight temptation—use it as fuel.

If impulsivity makes us act too soon, procrastination makes us act too late. To counter the urge to delay, Milkman introduces commitment devices—strategies for preemptively restricting your own freedom so you won’t sabotage future goals. Inspired by Odysseus binding himself to his ship’s mast to resist the Sirens’ call, these devices lock you into virtuous behavior before temptation strikes.

Hard Commitments

Some commitments are ‘hard,’ carrying real costs for failure. Green Bank in the Philippines offered customers ‘locked’ savings accounts they couldn’t withdraw from until reaching self-chosen goals. Despite sounding counterintuitive, participants saved 80 percent more than peers, proving that limitations can liberate. Similarly, MIT students who voluntarily set penalties for missing self-imposed deadlines wrote papers with 50 percent fewer errors.

Cash Commitment Devices

Apps like StickK expanded this idea into everyday life: you pledge money you’ll lose if you fail your goal. The threat of forfeiting even $100 transforms vague intentions into serious commitments. Entrepreneur Nick Winter staked $14,000 on finishing his book The Motivation Hacker—and succeeded. As Milkman notes, these tools mix economic logic with human psychology to make consistency contagious.

Soft Commitments and Pledges

Not everyone can stomach penalties. Soft commitments—like public pledges or accountability to a mentor—work through cognitive dissonance. In Los Angeles, doctors posted signed pledges not to prescribe unnecessary antibiotics, cutting misuse by one-third. Milkman’s student Karen Herrera lost 40 pounds by making weekly dietary pledges to her nutritionist. Seeing your own promise in writing creates identity-driven motivation.

Naïfs vs. Sophisticates

Milkman distinguishes between naïfs, who overestimate their willpower, and sophisticates, who accept their fallibility and plan defenses against it. Sophisticates use commitment devices; naïfs rely on hope. The goal, she says, is to become sophisticated—aware that human nature needs guardrails.

In every case, the rule is clear: bind yourself today so your future self can’t wriggle free tomorrow.

Sometimes failure isn’t about weakness—it’s about memory. We forget to vote, to take meds, or to follow through despite good intent. Milkman calls this ‘flake out,’ and identifies forgetting as the silent killer of change. The solution isn’t more motivation—it’s cue-based planning.

The Right Reminders

Not all reminders are created equal. A 2006 study found that telling drivers to ‘buckle up’ only worked when repeated at the exact moment they entered their cars. Delayed reminders failed entirely. Timing matters: prompts must arrive alongside opportunity. Milkman’s flu shot letters timed to clinic days increased vaccinations by 13 percent compared with generic reminders.

Implementation Intentions

Psychologist Peter Gollwitzer’s research shows that linking action cues to concrete triggers—“When X happens, I’ll do Y”—triples success. For instance, employees prompted to write down exactly when they’d get their flu shot were far more likely to follow through. This technique also works for voters: Todd Rogers found turnout rose 9 percent when citizens planned when, where, and how they’d vote.

Distinctive Cues and Checklists

The stranger the cue, the stronger its memory. In Milkman’s café study, patrons told to redeem coupons when they saw a three-eyed Toy Story alien did twice as well as those told to look for a cash register. For more complex tasks, checklists—like surgical safety lists popularized by Atul Gawande—prevent lapses through structured recall.

If forgetting sabotages your follow-through, don’t fight memory—design it. Create vivid cues, timely reminders, and clear checklists so that remembering becomes automatic.

Milkman reclaims laziness from shame. The human tendency to take the path of least resistance, she argues, is not a flaw—it’s efficiency. The trick is to design systems where doing the right thing requires less effort than doing the wrong one. She calls this strategy ‘set it and forget it.’

Defaults: The Power of Inaction

When a Penn Medicine IT developer made generic drugs the default prescription option, doctors’ use of generics jumped from 75 to 98 percent overnight. By exploiting inertia, this simple checkbox saved millions. Similarly, automatic 401(k) enrollment (the default system studied by Brigitte Madrian) revolutionized retirement savings. Defaults turn laziness into ally: if doing nothing yields the right result, people will do it.

Habits: Defaults for Behavior

When defaults can’t help, you need habits—your brain’s autopilot. Firefighter Stephen Kesting saved a colleague’s life because training made his instincts reliable under pressure. Habits are forged through repetition and reward. Milkman’s research with Google discovered that flexible habits stick best: employees who varied gym times built more robust routines than those locked to specific schedules.

Building Sticky Habits

Effective habit formation follows the Franklin-Seinfeld rule: track your streaks and avoid breaks. Franklin charted his 13 virtues daily; Seinfeld writes one joke a day without ‘breaking the chain.’ Tracking fuels accountability and pride. Even birth control manufacturers apply this logic—adding placebo pills to sustain habit loops through off weeks.

Milkman’s takeaway is simple: when laziness steers human behavior, rewire your environment so inaction produces success. Create smart defaults, automate good decisions, and ritualize routines until effort becomes optional.

One of the most surprising insights in Milkman’s playbook is that self-doubt—not ignorance—often blocks success. Drawing on the work of psychologist Lauren Eskreis‑Winkler, she shows that giving advice can be more empowering than receiving it. When you teach others, you affirm your own competence, triggering what psychologists call the ‘saying‑is‑believing’ effect.

Advice as Empowerment

In Milkman’s large‑scale study of 2,000 Florida high schoolers, students asked to give study tips performed significantly better later in the term. This flipped the traditional model of mentorship: confidence grows when we’re viewed as experts. Like drummer Mike Mangini, who built self‑belief when peers asked him for lessons, giving advice changes how we see ourselves.

Expectation Shapes Reality

Milkman connects this idea to psychologist Alia Crum’s research on placebo mindsets. Hotel housekeepers who were told their jobs counted as exercise lost weight and lowered blood pressure without changing routines—their beliefs reshaped their physiology. When mentors and leaders expect excellence, people rise to it. Milkman’s own advisor Max Bazerman exemplifies this: his unwavering faith in his graduate students’ potential helped them become world‑class academics.

Recovering from Failure

Self‑confidence is fragile. To prevent ‘what‑the‑hell’ spirals after mistakes, Wharton professor Marissa Sharif created ‘mulligans’—two emergency passes per week for missed workouts. The allowance makes persistence easier without erasing commitment. Coupled with Carol Dweck’s growth mindset—the belief that intelligence and ability can improve through effort—such framing turns setbacks into feedback rather than defeat.

Milkman closes with a reminder from psychology pioneer Claude Steele: affirming personal values before challenges improves resilience. Confidence, she insists, is not arrogance—it’s belief in your capacity to grow. To change for good, you must first believe you can.

Humans are herd creatures. Milkman’s chapter on conformity shows that social forces can be the most potent—and dangerous—drivers of change. We learn behaviors by copying peers, yet we risk losing autonomy when we follow crowds blindly. The goal is to use social influence strategically, not succumb to it.

The Power of Peers

At the Air Force Academy, economist Scott Carrell found that cadets randomly assigned to high‑performing squads improved their grades dramatically. Peer ambition rubs off. Similarly, when her friend Kassie Brabaw trained with vegetarian co‑workers, she became one herself by observing their practical habits—the ‘copy and paste’ method.

Social Proof and Descriptive Norms

People follow what feels typical. Psychologists Noah Goldstein and Robert Cialdini proved this with hotel towels: when guests learned that 75 percent of others reused towels, compliance rose 18 percent. The lesson—describe desirable behavior as common. Facebook’s voting experiment showed similar effects: seeing that friends had voted quadrupled turnout.

When Conformity Backfires

If role models feel unreachable, norms can discourage. At the academy, mixing top and bottom students backfired—the groups segregated, and weaker students performed worse. Likewise, workers told that 90 percent of peers saved for retirement gave up, feeling too far behind. Social proof works only when goals seem attainable.

Accountability and Recognition

Public visibility amplifies norms. When Michigan voters received letters showing neighbors’ voting records, turnout jumped 8 percent—but anger exploded. Milkman advises using social pressure positively: let people brag about good deeds rather than shame them for failures. Public recognition boards for green energy sign‑ups tripled participation with no backlash.

The secret is balance: seek inspiring peers, share progress publicly, and model attainable excellence. Conformity can elevate you—if it’s used consciously.

In her final chapter, Milkman confronts the toughest question: how do you make change last? After massive experiments with Angela Duckworth and 24 Hour Fitness, she realized that short‑term interventions fade quickly. People improved gym attendance during programs but relapsed once incentives ended. The insight from economist Kevin Volpp reframed her thinking: change must be treated like a chronic condition, not a temporary cure.

Ongoing Treatment for Human Nature

You wouldn’t stop insulin after a month of progress; human motivation needs continual reinforcement. Behavioral patterns decay at predictable rates, much like Opower’s home‑energy reports, where conservation dropped 10–20 percent yearly after reminders stopped. The lesson is consistency—make proven tools permanent fixtures of life.

A Personalized System of Tactics

Milkman revisits student Karen Herrera, who lost weight and kept it off by combining multiple strategies: scheduled weigh‑ins, accountability meetings, cue‑based meal planning, and temptation management. Each method addressed a different obstacle—forgetfulness, impulsivity, laziness, and confidence. Change endures when you tailor strategies to your unique adversaries and sustain them indefinitely.

Recalibrating and Redefining Goals

Sometimes goals fail not because of effort but because they’re poorly matched to your strengths. When a tactic stalls, reassess your opponent and redesign the plan. Milkman compares this to a tennis match: if your adversary changes tactics, so should you. And if one goal (like going to the gym) resists progress, redefine the broader purpose (getting fit) and find new paths—like morning walks or team sports.

In short, lasting change demands personalization, persistence, and periodic renewal. Treat self‑improvement as ongoing care—engineer your environment, monitor your motivations, and adapt your strategy. The fight to become who you want to be isn’t a one‑time battle—it’s a lifelong game.