When we’re designing pages, we tend to assume that users will scan the page, consider all of the available options, and choose the best one.

In reality, though, most of the time we don’t choose the best option—we choose the first reasonable option, a strategy known as satisficing.2  As soon as we find a link that seems like it might lead to what we’re looking for, there’s a very good chance that we’ll click it.

I’d observed this behavior for years, but its significance wasn’t really clear to me until I read Gary Klein’s book, Sources of Power: How People Make Decisions.3  Klein has spent fifteen years studying naturalistic decision making: how people like fire fighters, pilots, chess masters, and nuclear power plant operators make high-stakes decisions in real settings, with time pressure, vague goals, limited information, and changing conditions.

Klein’s team of observers went into their first study (of field commanders at fire scenes) with the generally accepted model of rational decision making: faced with a problem, a person gathers information, identifies the possible solutions, and chooses the best one. They started with the hypothesis that because of the high stakes and extreme time pressure, fire captains would be able to compare only two options, an assumption they thought was conservative. As it turned out, the fire commanders didn’t compare any options. They took the first reasonable plan that came to mind and did a quick mental test for problems. If they didn’t find any, they had their plan of action.

So why don’t Web users look for the best choice?

• We’re usually in a hurry. And as Klein points out “Optimizing is hard, and it takes a long time. Satisficing is more efficient.”
• There’s not much of a penalty for guessing wrong. Unlike the firefighters, the penalty for guessing wrong on a Web site is usually only a click or two of the Back button, making satisficing an effective strategy. Of course, this assumes that pages load quickly; when they don’t, we have to make our choices more carefully—just one of the many reasons why most Web users don’t like slow-loading pages.
• Weighing options may not improve our chances. On poorly designed sites, putting effort into making the best choice doesn’t really help. You’re usually better off going with your first guess and using the Back button if it doesn’t work out.
• Guessing is more fun. It’s less work than weighing options, and if you guess right, it’s faster. And it introduces an element of chance—the pleasant possibility of running into something surprising and good.

Of course, this is not to say that users never weigh options before they click. It depends on things like their frame of mind, how pressed they are for time, and how much confidence they have in the site.

Quoted from Don’t Make Me Think! A Common Sense Approach to Web Usability