The human brain is capable of 1016 processes per second, which makes it far more powerful than any computer currently in existence. But that doesn't mean our brains don't have major limitations. The lowly calculator can do math thousands of times better than we can, and our memories are often less than useless — plus, we're subject to cognitive biases, those annoying glitches in our thinking that cause us to make questionable decisions and reach erroneous conclusions.
Here are a dozen of the most common and pernicious cognitive biases that you need to know about.
Before we start, it's important to distinguish between cognitive biases and logical fallacies. A logical fallacy is an error in logical argumentation (e.g. ad hominem attacks, slippery slopes, circular arguments, appeal to force, etc.). A cognitive bias, on the other hand, is a genuine deficiency or limitation in our thinking — a flaw in judgment that arises from errors of memory, social attribution, and miscalculations (such as statistical errors or a false sense of probability).
Some social psychologists believe our cognitive biases help us process information more efficiently, especially in dangerous situations. Still, they lead us to make grave mistakes. We may be prone to such errors in judgment, but at least we can be aware of them. Here are some important ones to keep in mind.
Relatedly, there's also the positive expectation bias — which often fuels gambling addictions. It's the sense that our luck has to eventually change and that good fortune is on the way. It also contribues to the "hot hand" misconception. Similarly, it's the same feeling we get when we start a new relationship that leads us to believe it will be better than the last one.
Remember that time you bought something totally unnecessary, faulty, or overly expense, and then you rationalized the purchase to such an extent that you convinced yourself it was a great idea all along? Yeah, that's post-purchase rationalization in action — a kind of built-in mechanism that makes us feel better after we make crappy decisions, especially at the cash register. Also known as Buyer's Stockholm Syndrome, it's a way of subconsciously justifying our purchases — especially expensive ones. Social psychologists say it stems from the principle of commitment, our psychological desire to stay consistent and avoid a state of cognitive dissonance.
This is what the social psychologist Cass Sunstein calls probability neglect — our inability to properly grasp a proper sense of peril and risk — which often leads us to overstate the risks of relatively harmless activities, while forcing us to overrate more dangerous ones.
Observational Selection Bias
This is that effect of suddenly noticing things we didn't notice that much before — but we wrongly assume that the frequency has increased. A perfect example is what happens after we buy a new car and we inexplicably start to see the same car virtually everywhere. A similar effect happens to pregnant women who suddenly notice a lot of other pregnant women around them. Or it could be a unique number or song. It's not that these things are appearing more frequently, it's that we've (for whatever reason) selected the item in our mind, and in turn, are noticing it more often. Trouble is, most people don't recognize this as a selectional bias, and actually believe these items or events are happening with increased frequency — which can be a very disconcerting feeling. It's also a cognitive bias that contributes to the feeling that the appearance of certain things or events couldn't possibly be a coincidence (even though it is).
We humans tend to be apprehensive of change, which often leads us to make choices that guarantee that things remain the same, or change as little as possible. Needless to say, this has ramifications in everything from politics to economics. We like to stick to our routines, political parties, and our favorite meals at restaurants. Part of the perniciousness of this bias is the unwarranted assumption that another choice will be inferior or make things worse. The status-quo bias can be summed with the saying, "If it ain't broke, don't fix it" — an adage that fuels our conservative tendencies. And in fact, some commentators say this is why the U.S. hasn't been able to enact universal health care, despite the fact that most individuals support the idea of reform.
As individuals trapped inside our own minds 24/7, it's often difficult for us to project outside the bounds of our own consciousness and preferences. We tend to assume that most people think just like us — though there may be no justification for it. This cognitive shortcoming often leads to a related effect known as the false consensus bias where we tend to believe that people not only think like us, but that they also agree with us. It's a bias where we overestimate how typical and normal we are, and assume that a consensus exists on matters when there may be none. Moreover, it can also create the effect where the members of a radical or fringe group assume that more people on the outside agree with them than is the case. Or the exaggerated confidence one has when predicting the winner of an election or sports match.
The Current Moment Bias
Also known as the relativity trap, this is the tendency we have to compare and contrast only a limited set of items. It's called the anchoring effect because we tend to fixate on a value or number that in turn gets compared to everything else. The classic example is an item at the store that's on sale; we tend to see (and value) the difference in price, but not the overall price itself. This is why some restaurant menus feature very expensive entrees, while also including more (apparently) reasonably priced ones. It's also why, when given a choice, we tend to pick the middle option — not too expensive, and not too cheap.
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