I learnt a new word last week: ambivert. It was first coined by Kimball Young in 1927 and is defined as a person exhibiting features of an extrovert and an introvert. Finally, I had the solution to one of the nagging problems in my life: the forced division of people by the Myers-Briggs Type Indicator (MBTI) into either extroverts or introverts.
Most of us have suffered from one of the more common cognitive biases: the illusion of superiority. We all tend to overestimate our positive qualities and abilities, and to underestimate our negative qualities. Parents in particular do this with their young children. However, once you have studied statistics and learnt about the normal distribution you realise that half of us are below average and half of us are above average. Even more significant is that two-thirds of any population cluster within plus or minus one standard deviation. It is not called the bell curve for nothing.
Despite the popularity of the MBTI, I was never comfortable with its forced divisions: I or E, S or N, F or T, P or J. Yes, there is a division between male and female, but for most biological characteristics the normal distribution rules and this would include a personality factor such as extraversion.
Why is this distinction important? There is a widely accepted assumption that the best salespeople are extraverts. A recent study carried out by Adam Grant, the youngest tenured professor at the Wharton Business School, examined a software company with a large sales staff. It assessed where each salesperson stood on a one to seven introversion/extraversion scale, and then charted how much they sold over the next three months.
It comes as no surprise that the strong introverts (the people represented on the left of the chart’s horizontal axis, around one and two) were not very effective salespeople. But the strong extraverts (those over to the right, around six and seven) weren’t much better. The best were those in the middle, known as ambiverts.
More than 10,000 companies, 2500 colleges and universities, and 200 government agencies in the United States use the MBTI. And more than two million people take the test annually and are accepted, either into employment or for promotion, or rejected accordingly. Yet, despite its widespread use, the test is highly questioned by the scientific community. No major journal has published research on the MBTI, which academics consider a strong repudiation of the test’s authority. Carl Thoresen, a long-time and highly regarded professor of psychology at Stanford, is the Chairman of the company that markets Myers-Briggs, CPP. Yet of the roughly 150 papers he has published in his career, there isn’t one mention of Myers-Briggs.
Please note that I am not arguing against personality tests. There has been considerable progress in personality testing since the MBTI was first published 50 years ago. Tests such as the Five-Factor pass reliability and validity tests, unlike the Myers-Briggs, are based on legitimate scientific models, such as the normal distribution. A science-based personality test can reduce the people risk when hiring or promoting someone by around half. Yet many organisations continue to use Myers-Briggs, despite it being an instrument rejected by the scientific community.
I am reminded of the words of Tim Minchin:
“Science adjusts its views based on what’s observed. Faith is the denial of observation, so that belief can be preserved.”