People who consider themselves fully rational individuals are ignorant about basic psychology and their own minds.
It is easy for white men in science, technology, engineering, and math (STEM) fields to perceive themselves as more rational than other groups, because our society associates rationality with whites, men, and STEM professionals. When white men in STEM fields believe in this stereotype, they might assume that bias is more common in non-white people, women, and people in the arts, humanities, and social sciences. After all, these other groups seem to want to discuss bias more often, and unexamined associative “reasoning” would link bias to those who bring up the topic of bias. Under logical scrutiny, however, it does not follow that the act of thinking about bias makes one more biased.
A basic tenet of contemporary psychology is that mental activity can be unconscious. Unconscious simply refers to any mental activity that is “not conscious”, and it is not equivalent to the unscientific New Age concept of the Subconscious. A good example of unconscious mental activity interfering with conscious intentions is the Stroop effect (right). If you try to name the colours of the colour words aloud, the first set of colours will be easier to name than the second set of colours, because you unconsciously read the words. This means that you do not have full control over your thoughts and behaviour, and your willpower or logical reasoning cannot overcome the unconscious cultural bias of being able to read in English. Of course, there are other unconscious cultural biases aside from English literacy bias.