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. We tend to be put off by individuals, groups, and news sources that make us feel uncomfortable or insecure about our views. It's this preferential mode of behavior that leads to the often unconscious act of referencing only those perspectives that fuel our pre-existing views, while at the same time ignoring or dismissing opinions, no matter how valid that threaten our world view. And paradoxically, the internet has only made this tendency even worse.

Ingroup Bias

Somewhat similar to the confirmation bias is the ingroup bias, a manifestation of our innate tribalistic tendencies. And strangely, much of this effect may have to do with oxytocin the so-called "love molecule." This neurotransmitter, while helping us to forge tighter bonds with people in our ingroup, performs the exact opposite function for those on the outside it makes us suspicious, fearful, and even disdainful of others. Ultimately, the in-group bias causes us to overestimate the abilities and value of our immediate group at the expense of people we don't really know.

Anchoring Effect

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.