Let’s define a bias as a pre-conceived notion that may not have any correlation to reality. Everyone’s thinking is subject to such biases which have deleterious effect on decision making, problem solving and learning abilities. Here’s a list of biases to be aware of

The confirmation bias leads us to try to prove our existing notions and hypothesis. Rather than critically looking for evidence that contradicts our pet hypothesis, we try to confirm it, thus ignoring or downplaying evidence to the contrary. This is a big problem in science and numerous methods have been designed to deal with the confirmation bias. My favorite example of the confirmation bias is the Ptolemaic solar system model and its assumptions that a) the earth is at the center of the solar system and that b) all planets move in perfect circles around that center. Trying to make these objectively false assumption congruent with astronomical observations let to fantastic contortions. The Ptolemaic system was accepted for more than 1000 years as unquestionably true. Such is the power of the confirmation bias.

The hindsight bias (I-knew-it-all-along effect) makes past results appear more probable than they objectively are. The hindsight bias greatly affects our view of history.

The clustering illusion makes us see pattern where there are objectively none. Our brains have evolved to quickly recognize and take advantage of order (patterns) but we sometimes look for order where there is none. Suppose you tossed a fair coin three times and get three ‘heads’. What’s your chance of getting ‘heads’ on the forth throw?

The recency effect is the tendency to give more weight to recent data points and experiences. More recent events are better remembered and thus more relied upon when looking for solutions to problems.

The anchoring bias influences negotiations in that the first person to state a number will force the other person to state a new number based on the first (the anchor), even if the first number was completely random.

The overconfidence effect leads us to overestimate our abilities or the level of confidence we place on our ‘facts’.

The fundamental attribution bias leads us over-emphasize dispositional, or personality-based, explanations for behaviors observed in others while under-emphasizing situational explanations. This can greatly affect the quality of our social interactions.