4.4 Biases
It can be attractive to think of ourselves as objective decision makers, weighing the pros and cons of any given situation and making a decision based on the evidence available. However, a very large amount of research has demonstrated that any decision we make, including which applicant to hire or whether a suspect is guilty, is prone to bias. In other words, decisions are affected by who we are, the opinions and values we hold and our previous experiences, and this bias can happen without our knowing and even if we do our best to try to prevent it.
Known as unconscious, or implicit, bias, the stereotypes and general opinions we hold about a subsection of the population can strongly affect any decision we make about an individual person. This means that someone’s ethnicity, sex, sexual identity and age will affect how we perceive that person and in turn affect any decision we make about them.
Other forms of bias arise from the way in which we tend to process information. This includes confirmation bias (Nickerson, 1998), which is the tendency people have to focus on information that is likely to confirm their existing views on a topic. In a police investigation, confirmation bias can mean that officers may concentrate on evidence of guilt when investigating a likely suspect and downplay, or ignore altogether, evidence and routes of enquiry that would establish that suspect’s innocence.
Decisions can even be biased by the order in which information is presented, with the first information encountered acting as an ‘anchor’ (Tversky and Kahneman, 1974). This effect, known as anchoring, means that the first thing revealed about someone may gain more significance than subsequent information.