Photo by Felix Russell-Saw on Unsplash

What makes humans so special? Our ability to reason may be what most distinguishes us from other animals. We can consider our motivations, plan ahead, and look back on what we’ve done to understand how it went. But we are far from omniscient: our brains are designed to be efficient rather than perfect (if perfect is even possible). Because of this, we frequently make errors in judgement, and even convince ourselves of having made decisions that others made for us.

We regularly take shortcuts in our reasoning. Intuition plays a dominant role in our decision-making and this is not always a bad thing. It means we make quick decisions when it matters. When dogs see a frisbee flying in their direction, they don’t need to model the exact trajectory and flight speed of the object as it moves through three-dimensional space. Instead, they simply move to keep a steady optical angle between themselves and the object. When the ball is approaching in a straight line, they are likely to be in a good position to catch it. And don’t assume that dogs use this system because they’re too stupid for something more advanced. Professional baseball and cricket players use this same shortcut, and perform incredibly well with it.

Photo by James Ting on Unsplash. Adapted by yours truly.

When you need to make quick decisions, these shortcuts based on the simplest sources of information may be the best option. In fact, the advantages of this intuitive decision-making may not be exclusive to decisions under time pressure. Even some business decisions that don’t necessarily depend on speed may be most accurate when using intuitive assumptions rather than complex statistical models. When assessing whether someone is likely to be a repeat customer, a shortcut based on when the customer last bought a product performs better than a complicated model that accounts for overall customer dropout rates, purchasing distributions, and customer lifetime distributions. Next time you sit for hours thinking about which of five backpacks to buy — analyzing their colors, sizes, styles, brands, etc — maybe you should stop yourself and just click to buy the cheapest so that you can go out and do something more worthwhile.

Shortcuts or “heuristics” are fantastic tools, but in the modern world, they often lead us astray. We can easily be caught in the midst of irrational and biased reasoning. For example, when we hear a description of a person and are then asked to judge the probable truth of different statements about them, we may well be inclined to talk nonsense. Imagine the following scenario. Linda is “31 years old, single, outspoken and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations”. Knowing that about Linda, how would you rank these statements in order of likelihood:

Linda is active in the feminist movement Linda is a bank teller Linda is a bank teller and is active in the feminist movement

People generally believe that 3) above is more likely than 2). This is because of the ‘representativeness heuristic’. Activity in the feminist movement feels as though it would be representative of Linda given her description, so we place a lot of weight on that statement. So much weight in fact that we believe it’s more likely Linda is a bank teller and a feminist, than just a bank teller with no additional statement about her. If you can’t quite intuit why this is a fallacy (the conjunction fallacy to be specific), just replace the feminist part of 3) with any other neutral descriptor. It’s easier to see why you’d rather put your money on Linda being a bank teller than both a bank teller and someone who enjoys flying kites. One of the statements is demanding only one thing to be true while the other is demanding both that thing and an additional qualifier to be true. When uncertain, the statement with an additional demand must be less likely by any logical standard.

Now and then, our brain just plain makes things up. If I ask you to choose between A or B, and you choose A, what do you think you’d say if I asked “So why did you choose B?”. In a conversation where you didn’t know this was coming, you may not even bat an eyelid. You’d go on to explain exactly why you chose B and why B is so great.

Photo by Vladislav Babienko on Unsplash. Adapted by yours truly.

In one amusing experiment, men and women were shown two photos of female faces, and asked to choose which they found more attractive. The researcher then gave that photo to the participant for a closer look, and asked them to explain why they chose that photo. Unbeknownst to the participants, on some trials the sneaky researcher switched the photos with a subtle trick that meant the participants were now explaining why they chose the photo that they did not choose. But rather than acting surprised and complaining that they chose the other photo, most participants began to reel off the reasons why this face — the face they did not choose — was the most attractive. Sometimes, they would cite reasons that could only apply to their originally chosen photo, in full view of a face entirely inconsistent with their reasoning (e.g. “because she was smiling”, when the woman in the new photo looked conspicuously miserable). Other times, they would cite reasons that only applied to the new photo, and could not have applied to their original choice (e.g. “I like earrings!”, when the original photo displayed no jewelry whatsoever). And occasionally they would simply invent excuses about how the woman they were seeing at that moment was “very hot” or had “more personality” about her, in spite of the fact that they originally judged her to be lower in those traits.

Whatever the specifics of the confabulations, people are certainly willing to deceive themselves. This level of self-deception and post-hoc rationalization does not only apply to judging physical attractiveness. You can find the same patterns of choice blindness when it comes to political opinions and even moral attitudes. Perhaps we’re not as inflexible and resistant to change as it commonly appears. All it takes is for someone to fool us into thinking that we’ve already changed our minds.

When we reason ourselves into a void, it’s easy to become distrustful of the squishy organs sitting inside our heads. But that would be expecting too much from your brain. It’s great at its job precisely because it takes so many efficient shortcuts. When a lion is spotted nearby, the person who immediately thinks “run” is likely to make a lot more progress in life than the person who sits analyzing the lion’s distance, speed, size, and probable hunger levels. Our intuitions are certainly capable of embarrassing us, and it’s always worth quadruple-checking our thinking process. The modern demands of societies, economies, and the internet, are unlike anything that humans ever experienced in their evolutionary history. So the occasional snafu or two should be expected when we try to make sense of it all. Let’s just hope we can limit the damage with a little extra self-awareness.