Design for the mental shortcuts and limits people have

The human brain doesn’t carefully think over every decision. The brain evolved to balance speed, efficiency, and survival, which means it relies on shortcuts, gets tired, and often chooses the path of least resistance, aka the path that requires the least amount of effort.

Herbert Simon, an economist and cognitive psychologist who won the Nobel Prize in Economics in 1978, was one of the first to formalize this idea. His theory of bounded rationality showed that humans don’t optimize every decision. Instead, they satisfice (Simon, 1955).

This creates a problem for product builders.

Why?

Because the perfectly rational, endlessly focused user many products are designed around doesn’t really exist.

In other words, people don’t search forever for the perfect answer. They stop when they find an option that’s good enough, and they use mental shortcuts instead of thinking through every option. The more mentally taxed they are, the less likely they are to carefully evaluate every choice.

Designing for a user who carefully evaluates every option is designing for a fiction.

Here’s what designing for the actual human looks like.

Cognitive load is definied the amount of mental effort a task requires.

When a task requires too much mental effort or creates a high cognitive load, performance suffers because working memory has limits (Sweller, 1988).

Every unnecessary element, every extra step, every unexplained option, and every piece of information that doesn’t need to be there creates more work for the brain. And that work adds up.

In practice, reducing cognitive load means:

More choices sound like a better experience, but every additional option creates another decision someone has to make.

When users have to compare too many options, they spend more mental energy deciding instead of moving forward. The goal isn’t to remove choice. It’s to reduce unnecessary decisions so people can focus on the choice that actually matters.

Research on the paradox of choice found that more options don’t always lead to better decisions. In some situations, they can increase uncertainty and dissatisfaction (Schwartz, 2004).

Iyengar and Lepper (2000) demonstrated this in their famous jam study, where researchers set up a tasting booth with either six or twenty-four jam options.

While the larger display attracted more shoppers to stop and sample, the smaller selection led to a higher percentage of shoppers making a purchase.

The takeaway for product builders is that more options can get people interested, but too many options can make it harder to choose.

Fewer choices, less friction.

Working memory—where you hold and use information for a short period while you're doing something—is limited. This means people can only keep a small amount of information available while they are thinking through a task (Miller, 1956). The exact amount depends on the complexity of the information and the task itself.

Information is easier to process when it is broken into smaller pieces.

When everything is presented at once, people don’t magically become more focused. They are more likely to miss information, make mistakes, or struggle to complete the task.

Instead of giving people everything at once, group related information together, introduce things step by step, and make complicated processes easier to follow.

When people have to stop and figure out what to do next, they use more mental effort to move forward.

Good design reduces unnecessary decisions by making the next step easier to see. This can mean recommending an option, pre-selecting a common choice, or guiding someone toward the action most people need to take.

People are more likely to follow through when the choice feels simple, and the path is clear

The user you’re building for is not sitting down with unlimited time, attention, and patience. They are making decisions while distracted, busy, and trying to get things done.

Designing for real humans means accounting for those constraints instead of expecting people to work around them.

Iyengar, S. S., & Lepper, M. R. (2000). When choice is demotivating: Can one desire too much of a good thing? Journal of Personality and Social Psychology, 79(6), 995–1006.

Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review, 63(2), 81–97.

Schwartz, B. (2004). The Paradox of Choice: Why More Is Less. New York, NY: Ecco.

Simon, H. A. (1955). A behavioral model of rational choice. The Quarterly Journal of Economics, 69(1), 99–118.

Sweller, J. (1988). Cognitive load during problem solving: Effects on learning. Cognitive Science, 12(2), 257–285.