A cognitive bias is pattern of deviation from norm or rationality in judgment, whereby inferences about other people and situations may be drawn in an illogical fashion.
It affects the decisions and judgments that people make.
We human like to consider ourselves as rational being but we are emotional beings.
The human brain is both remarkable and powerful, but certainly subject to limitations.
Cognitive biases are just one type of fundamental limitation on human thinking.
Cognitive biases are often a result of our attempt to simplify information processing.
They are rules of thumb; that help us make sense of the world and reach decisions with relative speed.
Unfortunately, these biases sometimes trip us up, leading to poor decisions and bad judgments.
A very famous cognitive bias is anchoring. It is the common human tendency; to rely; too heavily on the first piece of information offered when making decisions.