Hooked

Eyal presents a four-stage model for building products that create habitual use: trigger, action, variable reward and investment. External triggers such as notifications bring a user in initially, and the objective is to attach the behaviour to an internal trigger, usually a negative emotion such as boredom, loneliness or uncertainty, so the product becomes the automatic response to that state.

The action stage draws on BJ Fogg's behaviour model, requiring motivation, ability and a trigger to coincide, with the practical instruction that reducing the effort required works better than increasing motivation. The variable reward stage draws on the finding that unpredictable rewards produce stronger and more persistent behaviour than fixed ones, and Eyal divides rewards into those of the tribe, of the hunt and of the self. The investment stage argues that users who put work into a product, through content, data, followers or configuration, value it more and load the next trigger themselves.

Eyal includes a manipulation matrix that asks whether the maker uses the product and whether it materially improves users' lives, and argues that products failing both tests should not be built. He has since written Indistractable, which addresses the user side of the same mechanics.

The ethical problem is not resolved by the matrix. The book gives a working method for building compulsive products, and the subsequent decade of evidence about social media effects has made it read differently than it did in 2014. The research is reported secondhand and the case studies are selected. The model itself is accurate as a description of how habit-forming products work, which is precisely why the ethical framing matters more than Eyal allows.