Heuristics: The Original Three

Anchoring:

The common tendency to rely too heavily on the first piece of information we are offered (the ‘anchor’) when making a decision.

Availability:

Giving preference to information and events that are more recent, that were observed personally, and that were more memorable.

Representativeness:

The presumption that once people or events are categorized, they share all the features of other members in that category.