As our brains attempt to interpret the information around us, they also try to simplify and categorize it. A cognitive bias is an unconscious error we make as our brains try to simplify and process the complex world and information around us. This could occur through the use of mental shortcuts, also known as heuristics, emotions, other social factors, and more.
Although there are some standard cognitive biases all humans are prone to, the specific results of them do vary from person to person because they are filtered through our own experiences; past and present. They affect our actions, the way we make decisions, the way we interact with others, and more.