A man stood in the L’Enfant Plaza metro station in Washington DC and started to play the violin. It was a cold, January rush hour morning. Over a period of 45 minutes, he played six Bach pieces. Only seven people stopped to listen. 27 gave him money but continued to walk. He collected $32 in tips. When he finished playing and silence fell, no one noticed.  

The violinist was Joshua Bell, one of the best musicians in the world. He played some of the most intricate pieces ever written, on a violin worth $3.5 million. Three days before this, Joshua Bell had sold out a theatre in Boston where the average ticket price was $100.

The unconscious bias people held about street performers led over a thousand people to walk past a unique performance by a highly talented classical musician. Are you turning away or discounting the Joshua Bells of your industry because of their appearance, their accent or some other factor that doesn’t relate to the job?

Most of us firmly reject stereotypes and would answer that question with a resounding “Of course not!”  Unfortunately, your own brain may be getting in the way of your good intentions. The problem is that, unconsciously, you may be exhibiting bias that you’re not even aware of – and this can subtly affect the way you perceive and interact with others. 

One of our brain’s best tricks is its ability to recognise and act on patterns. This ability can make us extremely efficient, as we can recognise a pattern and act on it, rather than interacting with everything in the world as if we are seeing it for the first time. It’s a way of bringing order to the chaos around us. For example, we can use pattern recognition to know that one animal is a wolf and another is a cocker spaniel. That recognition allows us to make assumptions, which can either be based on our own experiences (dogs are friendly or ferocious) or on information we have gained second-hand from others (wolves are dangerous).

Our unconscious mind looks for these patterns all the time. If we see two things occurring together, our pattern recognition habit leads us to expect to see them together in the future. In other words, when we see one, we infer the presence of the other. Unfortunately, this ability to see and recognise patterns can also cause us to make erroneous assumptions. A musician playing for spare change in a train station, for example, may actually be outstanding!

One of the ways we categorise things, some social psychologists say, is through a hard-wired preference to respond positively to people who look, sound and act like we do. This process is referred to as social categorisation. It appears to begin at an early age, with babies as young as four months processing the faces of adults. Brain imaging scans reveal that when we are shown images of faces that differ from our own, a part of our brain is activated that alerts us to possible danger. This may be a throwback to ancient times, when danger often came from those outside our immediate group. Today, however, this means that associations and biases can be activated when we come across a member of a different group, even if we consciously reject group stereotypes. 

Social categorisation has its benefits. We use it to make inferences about people, so we know how to interact with them. We can, for example, infer what a person’s intentions or goals may be, what skills and knowledge they may have and what their position might be in our hierarchy. 

However, this habit can also lead us to see patterns even where none exist – believing in lucky numbers, for example – or it can direct us to see patterns that may lead to an unconscious bias for or against a particular group. For example, several studies have shown a positive bias towards taller men, including one published in the Journal of Applied Psychology a few years ago that concluded that, over the course of a 30-year career, a person who is six feet tall is likely to earn $166,000 (nearly £107,000) more than someone who is a foot shorter.

In another study, 238 psychologists were given the same CV to review. When the CV was identified with a male name, the applicant was 10% more likely to be recommended for hire than when the candidate was identified as a female. The gender of the reviewer did not appear to make a difference.

So how can you moderate your unconscious bias? Here are five tips:

• Begin by recognising that you – and everyone else – have unconscious biases. Take the Harvard Implicit Association Tests* at https://implicit.harvard.edu to learn more about your conscious and unconscious preferences.  
• Where you find unconscious bias, make the effort to learn more about members of that group. Unconscious bias seems to thrive on a lack of information.
• Try using memory joggers – written notes or images – to remind yourself of the need to remain vigilant and objective.    
• Keep in mind that, when you are under pressure or when there is a great deal of uncertainty, unconscious bias is more likely to play a role in your decision making. Your brain simply doesn’t have the processing capacity to check your objectivity. If you are under pressure, try taking a break or using another mechanism to reduce your stress.
• When taking or recommending personnel actions, look at the basis for your decisions and ask yourself if there is objective data to support your action or if unconscious bias is at work. Did that person you interviewed remind you of a childhood friend and did that lead you to be slightly more supportive in the interview than you would have been otherwise? Does that employee who is seriously overweight deserve the performance rating you gave them or do you, like 40 percent of medical students in a recent study, have an unconscious bias against overweight people?

Having unconscious biases doesn’t mean that you’re a bad person, just that you’re a human being. Becoming aware of your biases – and those of others – takes you one step closer to managing the predicament.

* The Harvard Implicit Association Tests are a series of 10-15 minute tests to assess your unconscious preferences for randomly-assigned topics such as ethnic groups, political issues and styles of music. Each test concludes with a summary of your results. Maintained by researchers from Harvard University, the University of Virginia and the University of Washington, the tests have been used in 20 countries over the past 10 years.