From Cambridge Dictionary of Sociology:
Bias refers to those aspects of the social research process that may skew the findings in some way. The main identified sources of bias concern the researcher or informant, the measurement instruments or methods, and the sampling procedures. Biased measures fail to do a good job of measuring the things they are purported to measure and therefore lack validity. Biased samples are not representative of the relevant population or set of cases they are meant to reflect.
There are hundreds of different types of bias that have been identified. These different categories of bias have multiple bias examples within them. Some commonly recognized types of bias are:
A cognitive bias is a systematic pattern of deviation from norm or rationality in judgment. Individuals create their own "subjective reality" from their perception of the input. An individual's construction of reality, not the objective input, may dictate their behavior in the world.