According to psychological research, we humans do indeed believe people are prone to bias… but only others, of course. We tend to believe that our actions and reactions are exempt from conscious or subconscious biases, but others are certainly capable of bias.
Researchers of human behavior believe that bias and stereotypical thinking are the result of our evolutionary response to survival. We have learned over the centuries to quickly categorize and evaluate other people and our surroundings on both conscious and subconscious levels so that we can make snap judgments and decisions that keep us alive. Researchers also believe that our environment and the culture surrounding us before we reach the age of five influence our biases, as well. (Source: Psychology Today)
But regardless of our evolutionary proclivities or immediate surroundings or past cultural environments, there is a way to shed our biases when we’re writing. When choosing our diction, pronouns, and subject matter, we have an opportunity to evaluate words on the page repeatedly before we share them with others.