Decision Fatigue

You sit at the piano. The lights shine upon you. You stretch out your arms and crack your knuckles. The conductor taps his baton on the podium. Tap. Tap. Tap. The audience quiets to silence. You take a deep breath, and the music begins. You play several notes from muscle memory, a few through conscious recall, and others by viewing the sheet music. You play and play, making decision after decision, going from chorus to bridge to melody and back. Every note creates an opportunity to be played off-key—to be played out of tune. The more you play, the greater the chance you will eventually fumble. Sweat lines your brow, you play and play again. Fatigue sets in. Your aching fingers strain to reach the farthest key and… Oh, no! Your hand slips and strikes the wrong note. The audience gasps. You stand back up and walk out of the room, never to return.

From playing a piano to inputting spreadsheet data, the quality of decisions decreases over time during an individual session.² The more decisions you make, the greater the likelihood you will eventually make a lousy one. And like a humbled concert pianist, a user may abandon her attempt to use a piece of software and never return to it again.

One of the more prevalent and mistaken beliefs about user experience is that users want interaction for the sake of interaction. This view often masks itself in the cloak of marketing—a phantom that runs onto the stage of a software interface, excites the audience, then retreats into the darkness. Unnecessary image carousels, overcrowded form fields, and futile sharing tools, are frequent culprits. Such distractions burden audiences with additional decisions to consider. Introduce too many considerations and you will fatigue your audience. They will make poor choices. They will blame themselves, as well as your software.

In earlier chapters, we discussed Hick’s Law.³ This law showed us that the number of choices within a given decision can sometimes work against the decision-making process. Though decision making is a complex endeavor, choices often slow users down. We witness Hick’s Law at work when we observe users interacting with shopping carts: introduce a choice and you will create an opportunity for users to abandon their purchase (see Figure 22-1). Conversely, we see the benefit of reducing choices within the design of single-page websites . After all, if you want to avoid users getting lost within your site, one surefire strategy is to never take them anywhere.

Researchers have studied decision fatigue in relation to ego since the late 1990s. In a series of experiments⁵ conducted by Dr. Roy Baumeister and his colleagues, researchers asked subjects to perform acts of willpower, such as resisting the temptation to eat chocolate cookies. Afterward, subjects were asked to solve complex puzzles. The experiment showed that after performing an act of volition (e.g., resisting eating a cookie), people were less able and willing to make complex decisions. Willpower and decision making appears to originate from a common pool of cognitive resources. Subsequent experiments also demonstrated the inverse relationship: complex decisions reduced subjects’ ability to perform acts of volition. Decision fatigue and ego depletion go hand in hand. However, ego depletion is not without controversy. Several recent studies have cast doubt on the theory, whereas other studies further bolster its claims.⁶

When we ask a user to make a decision, we reduce her willpower and ability to make the next one. Though fatigue may seem unavoidable, we mitigate its effects by decreasing the number of decisions a user must make. Simplify. Reduce. Remove. Fewer decisions equal less fatigue. Our users glide through our software unencumbered. Our job is to design experiences containing only what is necessary. We may have fewer notes to play, but each will ring truer. That is a tune we all wish to hear.

Key Takeaways

Questions to Ask Yourself