Book Review: Hooked: How to Build Habit-Forming Products

Published Feb 2, 2018

The fact that technology can be highly addictive is no surprise to anyone familiar with the inexplicable urge to check email at 2pm on a Saturday. Or anyone who sits bolt upright at the bing of an inbound text. Pavlov himself may have blushed to see how his theory has held up.

It’s also no great surprise that these addictive qualities are often quite intentional, deliberately engineered into the products that we feel so compelled to use, often dozens of times a day.

Nir Eyal’s important book Hooked: How to Build Habit-Forming Products (Penguin, 2014) explores the mechanics, economics, and ethics behind technology products that draw us in and hold us rapt. He offers an instructive methodology for product leaders considering what it takes to design habit-forming products; and, crucially, a framework (which boils down to a modest variation on the Golden Rule) for considering the ethics of what has the potential to become an instrument of manipulation, if not engineered addiction.

Eyal suggests that habit-forming products create an itch that demands to be scratched. The “Hook” model he proposes begins with a trigger, which drives an action, which yields a reward, which compels the user to make an investment back into the product—which, in combination, compels them to use the product over and over again. It’s a virtuous—or virulent—cycle.

The trigger: Activating user behavior

Eyal describes triggers as the actuators of user behavior. These can be external and internal. External triggers are the manufactured stimuli that drive initial engagement and trial, often through advertising and other paid means; through relationships and social pressure; and through conveniently located product real estate co-opted to trigger new user actions.

Internal triggers happen more organically. These are the side effect of the product experience itself, where the designed elements and game mechanics of the product create impulses with users that can become habits—and habits that can become compulsion or even addictions.

The action: Satisfying the need

Eyal describes the action as the simplest user behavior in anticipation of the reward. He says the action depends on two things: motivation and ability. Motivation comes from an understanding of the user and his or her desires, goals and needs. This empathy allows us to design rewards systems that compel users to take action. Ability is the most basic element of a product experience, offering the fastest possible path from trigger to reward. Here, friction can mean frustration–and frustration can mean failure, where the user never bridges the gap between the trigger and the reward beyond.

The reward: Feeding the beast

Anyone with who has taken an intro to psych class knows about Pavlov and his dog, the famous experiment that proved the principle of classical conditioning. Pavlov demonstrated how a simple stimulus paired with a reward created a conditioned response. A century later, American psychologist B.F. Skinner expanded Pavlovian conditioning with the principle of variability, which shows how the introduction of a variable reward system created an even more potent craving.

Similar principles apply in the design of habit-forming products. Eyal makes the important point that product rewards should be variable. After all, what compels a slot machine junkie to feed the beast isn’t the knowledge of what’s next to come; it’s the not knowing that becomes the thrill of the hunt. In fact, if the rewards were predictable, the avid gambler might soon see the one-armed bandit for the dull companion it most certainly is.

The investment: Skin in the game

Finally, Eyal discusses the idea of building in mechanisms that allow users to invest back into the product. Eyal cites what Dan Ariely calls “The IKEA Effect,” which suggests that humans generally attach more value to things they’ve had a hand in making.  

The IKEA example is obvious enough: the consumer who labors over the assembly of some obscurely named TV console fashioned of flat-stacked particle board will probably hold the product in higher esteem than it possibly deserves (maybe short of some priceless heirloom, but greater than the sum of its infinite plastic parts). In the world of technology products, a now classic example of this sort of investment is user-generated content. With Ariely’s theory, Eyal suggests that, on the margin, users tend to value their own contributions substantially more than third parties and nearly as highly as the contributions of bona fide experts.

Ultimately, as product leaders, we’re all motivated to create products that our customers can’t live without. Part of this comes from deep user understanding and empathy. But it also comes from the canny application of user psychology and behavioral economics.

Of course, applying these theories requires a clear acknowledgment of the harm they can do when they’re misappropriated or carelessly applied. While there are examples of products that have won through deleterious means, these are often passing fads. It’s the products that keep us coming back for the right reasons that, habit or not, earn our enduring love and loyalty.

Note: Nir Eyal will discuss how to create habit-forming products as a headline speaker at Pendomonium 2018, March 20-21, in Raleigh, NC. Register now: (Full disclosure: Pendomonium and ProductCraft are produced by Pendo, my employer.)