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5 Myths & Misconceptions About Personality Testing

It's time that we busted some of the most common myths and misconceptions that surround personality testing. Especially as testing is becoming more prevalent in the workplace, it’s important to be armed with information and understanding.

1) People Are Either Left Brained or Right Brained

Brain lateralisation is a well-documented phenomenon that refers to how certain cognitive processes are handled by the left hemisphere, while other processes are handled by the right. However, the idea that some people are more dominant users of the left hemisphere (associated with logic) and others are more dominant users of the right (associated with creativity) has no scientific support. Not only has Michael Gazzaniga, the “godfather of modern split-brain science,” repeatedly stated that his colleagues’ work on brain lateralisation has been greatly over-simplified in pop culture, but brain scans of thousands of participants have shown that people use both sides equally in a range of tasks. Being good at math is not confined to one side of the brain, and being good at art is not confined to the other.

2) People Are Either Introverted or Extraverted

As reported by the Wall Street Journal and other publications, research indicates that a significant proportion of population — perhaps as high as 70% — are ambiverts (a mixture of introversion and extraversion). For an “either/or” personality type classification model to be valid, population scores would need to resemble something known as a “bimodal” distribution. However, studies show that the preference for introversion or extraversion resembles a “normal distribution,” much like height, weight, and intelligence. If you imagine that everyone on the planet above 6ft was termed “tall” and everyone below 6ft was termed “short,” then you can begin to get a sense of the problem with the "either/or" approach. Only a minority of the population actually shows a strong preference for introversion and extraversion.

3) Personality Consists of Only 4 Dimensions, Like in Myers-Briggs Type Indicator (MBTI)

A study reported in the Harvard Business Review detailed a list of common but false assumptions made by HR managers. Of the 1,000 HR professionals surveyed, the study found that 51% believed “there are four basic personality dimensions, like in MBTI.” The Big Five model, which differs considerably from the MBTI classification approach, consists of five basic dimensions and is the most well accepted foundational personality model in the scientific community. There is ongoing debate as to whether there are more than five basic dimensions; however, there is no debate over the idea of there being only four - that’s just not accurate. 

4) Personality Testing Is a Pseudoscience, Like Astrology

Some people equate personality tests with astrology, which is widely regarded as a pseudoscience by the scientific community, and repeated tests have demonstrated that it performs no better than random chance (i.e., you get the same level of self-reported accuracy by mixing up people's zodiac signs). The scientific burden of proof remains on astrologers to demonstrate their claims.

The same is not true of modern psychometrics, in which test publishers have all the scientific data they need to build assessments that make testable, valid, and reliable predictions about human personality and behaviour. Astrology’s association with personality tests is somewhat understandable, since some assessments make vague statements that could seemingly apply to anyone (this is known as the Barnum effect).

It’s important to remember that personality testing is a very broad umbrella, encompassing thousands of individual instruments. Some tests are scientifically solid and are well respected by the scientific community. Others are based on personality theories than are well-past their expiry date, yet remain popular among the general public, perhaps due to novelty, attachment or simply a lack of awareness concerning industry advancements. All reputable tests come with validity and reliability studies using Cronbach's alpha, giving consumers a standardised way of assessing the credibility of any given assessment on the market. 

5) Personality Tests Are About Labelling or Pigeonholing People

Over the years, we have seen a number of inexperienced, poorly-trained facilitators use personality tests, not as a platform for discussion, but as a categorisation instrument for shutting people into boxes. Human personality isn’t a perfect science and models of personality, by their very nature, make generalisations. Unfortunately, many people assume that personality assessments have an omniscient power to peer into the depths of your soul and tell you who you are. At the end of the day, you define your personality; not a computer algorithm.

Assessments are valuable because they provide objective, non-biased data based on scientifically reliable population tendencies. This information serves as a starting point for awareness, understanding, discussion, clarification, reflection and refinement in relation to one’s individual situation. It’s vital — and this point can seldom be stressed enough — that assessments are debriefed with a well-trained facilitator, who is qualified to interpret the assessment results. Accredited facilitators, like good doctors, understand that the diagnostic equipment is useful as a starting roadmap, but what is often more important is the unfolding process of dialogue between two humans to help connect the dots. Bad facilitators will tend to operate from a more rigid perspective.

You may also enjoy reading the 6 Myths of Maslow's Hierarchy of Needs.

Theo Winter

Theo Winter

Client Services Manager, Writer & Researcher. Theo is one of the youngest professionals in the world to earn an accreditation in TTI Success Insight's suite of psychometric assessments. For more than a decade, he worked with hundreds of HR, L&D and OD professionals and consultants to improve engagement, performance and emotional intelligence of leaders and their teams. He authored the book "40 Must-Know Business Models for People Leaders."

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