Psst... based on the research you did, is there anything reliable you can tell us about personality and how it works?
The current commonly accepted personality model is generally referred to as the Big Five, and it's relatively rare in that it's as close as a consensus as you can reach in psychology. There have been tonnes of research that keep turning up the same general results. Research across cultures, with babies, with animals, self reported questionnaires versus descriptions, open ended versus multiple choice questions, relationships with biomarkers... Obviously they're not all exactly identical, because psychology is not an Exact science, but the results are always similar enough that as far as models go, it's about as solid as you can get.
So, what is this model? It very simply says that there are five big, independent character traits that people can vary in, easily remembered by the handy acronym OCEAN :
- openness to experience : how curious you are, how interested you are in culture and how much imagination you have versus how much you prefer to concentrate on practical things and how conservative you are (in the non-political meaning of the word)
- conscientiousness: how much do you care about efficiency, accuracy and being on time, versus how sloppy or disorganised you are.
- extraversion: you know this one. How much do you like/need interaction with other people.
- agreability: how nice you are. Are you generally well-disposed towards people or are you more distrustful?
- neuroticism: are you a big worrier or are you more laidback?
Now, all of these are phrased like it's a choice between two options, but what the Big Five model also keeps turning up is that these five are a spectrum, with a large majority of people being sort of in the middle. Most people dislike being alone all day but also get tired from being in big groups for a long time. Most people worry about bigger, important things but less about smaller things. Most people want to be accurate and careful in general but don't mind being a bit more sloppy when it matters less to them. In statistical terms, they all follow a gauss curve, which looks like this (with the vertical axis being the amount of people and the horizontal one the score out of ten you would get on a questionnaire) :
Which means that if you take a group of random 100 people, only a handful will be on the extremes of the spectrum (the party animal versus the recluse) while 60 to 70 people will have no real, strong preferences either way.
And that's why personality models that want to divide people up into distinct groups are, objectively, wrong. The differences between someone who scores 49 and someone who scores 51 on an extraversion scale are minimal, but those personality type theories will have you believe those two are radically different people. One of the major issues with the MBTI is, in fact, that a lot of people keep getting different results if they retake the test a few weeks or months later, exactly because of this reason : if you're an average scorer (and again, most people are), choosing between two extremes makes no sense and you're basically assigned a type at random.
The Big Five is by no means a perfect model. There's doubt whether it can really be applied that easily to non-western cultures. The interaction with mental health and neurodivergence is still unclear (are people with anxiety just extremely high on the neuroticism scale, or is anxiety a separate thing that influences the results?). But it's been replicated enough that the core of it is, at this point beyond doubt. Meanwhile the MBTI, Insights Discovery, Kolb's learning styles and all those other "you're either type A or type B" models that are rife in the business world are scientifically bullshit.
Personality doesn't come in types. Personality is a spectrum, with a few people in the extremes but the majority somewhere in the middle. And ignoring that in favour of putting people in neat but inaccurate boxes is very dangerous.
