As the name suggests, unconscious bias is something that we are vastly unaware of. It is instinctive and triggered by the brain making fast judgments of people and situations. The biggest influencers are our upbringings and surroundings, and how we have been encouraged to process personal experiences. The unconscious bias as a system saves us time and effort processing information, allowing us to spend more time on other tasks.
For the most part, our brains do a fantastic job of sorting through and categorising observations we make in our lives. Categories can be based on very simple criteria such as age, weight, sexuality, accent, social status and job title. But with over 150 biases, there is literally a bias for everyone.