The 12 cognitive biases that prevent you from being rational

i09 produced a great overview of some cognitive biases.

First, the difference 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).

Confirmation Bias

We love to agree with people who agree with us. It’s why we only visit websites that express our political opinions, and why we mostly hang around people who hold similar views and tastes.

Ingroup Bias

Ultimately, the ingroup bias causes us to overestimate the abilities and value of our immediate group at the expense of people we don’t really know.

Gambler’s Fallacy

We tend to put a tremendous amount of weight on previous events, believing that they’ll somehow influence future outcomes.

Post-Purchase Rationalization (aka commitment and consistency bias)

[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.

Neglecting Probability (aka Insensitivity To Base Rates)

It’s the same phenomenon that makes us worry about getting killed in an act of terrorism as opposed to something far more probable, like falling down the stairs or accidental poisoning.

Observational Selection Bias (Availability 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.

Status-Quo Bias

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.

Negativity Bias

People tend to pay more attention to bad news — and it’s not just because we’re morbid. Social scientists theorize that it’s on account of our selective attention and that, given the choice, we perceive negative news as being more important or profound.

Bandwagon Effect (aka social proof)

Though we’re often unconscious of it, we love to go with the flow of the crowd.

Projection Bias

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.

The Current Moment Bias

We humans have a really hard time imagining ourselves in the future and altering our behaviors and expectations accordingly.

Anchoring Effect

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.

Still curious? Check out the Farnam Street Latticework of Mental Models.