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Deciding, Fast and Slow

Reason can be just as fast as intuition

Many years ago when I was a student in Austria, a beggar approached me, and I offered her the change in my pocket.

“What, is that all you can give?” she demanded.

I turned away and quickly left with my cash in my wallet and my coins still in hand.

As I waited for the tram home, I debated whether to buy a ticket from the vending machine or not. It was late, and they rarely checked tickets at that time. Like other students, I’d gotten away with free rides before, and I was confident I could save a few shillings that night as well. Yet as the tram approached, I remembered a classmate who’d been caught without a ticket and had to pay a hundred shilling fine. I dropped some coins into the dispenser and grabbed my ticket just as the streetcar pulled up to the stop.

Traditionally, economists have assumed that humans are rational decision makers, yet in recent decades psychologists working in the field of behavioral economics have come to recognize that people are limited in their ability to make rational decisions. In some cases, such as when we have the time and the cognitive resources to think things through, we can be quite rational in our decision making. But when we’re constrained by time or bombarded with other things that demand our attention, we tend to make quick, gut-feeling decisions. In his 2011 book Thinking, Fast and Slow, psychologist and Nobel laureate Daniel Kahneman explains the so-called dual-process theory of decision making for lay audiences.

Going with your gut isn’t necessarily bad. We humans have evolved some pretty effective intuitions that usually lead us to very quick—and reasonably accurate—judgments, at least in the social realm. Likewise, taking the time to make a rational decision can lead us to what psychologists call “paralysis by analysis.” That is, we’re unable to make a decision in real time because we’re bogged down by slow reasoning processes. For example, there’s no rational process for deciding what to order for lunch, and so we just have to go with whatever feels right.

According to dual-process theory, intuitive thinking is fast, while rational thinking is slow. And so, psychologists often use reaction time to determine whether a participant in their experiment is using an intuitive or rational approach to solving the problem at hand. Yet, as social psychologist Anthony Evans and his colleagues point out in a recent article, a fast reaction time can correlate with either an intuitive or a rational decision process, depending on the particular task.

More specifically, these researchers point out that rational thinking can be just as fast as intuitive thinking, especially when the reasoning is straightforward. This is particularly the case in situations when we have to decide between helping another person or else protecting our own interests. The classical finding here is that people tend to help others when they process the situation intuitively but tend to be selfish when they think analytically. Giving a handout to a beggar may make you feel good, but in the end you’re out the money that you could have spent on yourself.

Evans and his colleagues argue that sometimes a rational decision comes just as easily to mind as an intuitive response. And that’s why reaction time can’t be used to determine whether a person has used an intuitive or analytical approach to arriving at a decision. Thus, my gut told me to hand the beggar the few coins in my pocket. But when confronted with the demand for more, it took little time to reason that I, as a foreign student, was on a limited budget and couldn’t afford a larger donation.

In other words, both intuitive and rational thinking can be quick. Instead, Evans and his colleagues argue, what slows thinking down is when we experience a conflict in goals. That’s why I waffled on the issue of whether to buy a tram ticket or not. Most likely I could have saved a little money, but only at the risk of having to pay a hefty fine. It’s not the rational thought process itself that delays the decision making but rather the conflicting interests that do so.

As I was writing this blog post, I went to Wikipedia to check some facts. And when I got to the site, a fund-drive window popped up. “If every Wikipedia user gave $3, this fund raiser would be over in an hour.” To give or not to give? I use Wikipedia a lot, and I’d hate to see it go away.

It's easy to ignore an online request for a donation. Yet I value the convenience of Wikipedia, and I believe I gave because I saw the value I'd get back from the donation (a rational choice) and not because I felt I ought to (an intuitive choice). And yet I didn’t take much time to deliberate. Rather, I quickly reached for my wallet and entered my credit card number.

There’s more to decision making than whether it’s done intuitively or rationally. Either process can lead to fast decisions. But when our goals conflict, it can take some time to make a choice.


Evans, A. E., Dillon, K. D., & Rand, D. G. (2015). Fast but not intuitive, slow but not reflective: Decision conflict drives reaction times in social dilemmas. Journal of Experimental Psychology: General, 144, 951-966.

Kahneman, D. (2011). Thinking, fast and slow. New York, NY: Farrar, Straus & Giroux.

David Ludden is the author of The Psychology of Language: An Integrated Approach (SAGE Publications).

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