One of my all time favourite topics is that of animal personality. In fact my PhD was centred around animal personality, using some nifty new technology to explore the phenomenon. Most of my papers are about how personality affects the lives of cows.

Don’t laugh. That’s genuinely what my PhD is in.

There are actually plenty of production and welfare reasons to study this in cattle, but today I want to talk to you about one of the basic concepts of personality.

Let’s Talk Science

You’ve heard people talk about personality traits or dimensions (I’ll use traits for the rest of this article), but what do you know about personality traits? I’m going to give you a very complicated sciency sounding sentence here, and by the end of this article, I think you’ll understand it.

Are you ready?

Are you sure?

Personality traits are a statistical construct based on the behavioural variation displayed number of individuals sampled.

Let me explain . . .

Weird World One

Pretend you only know five people in the whole world: Tom, Harry, Sheldon, Alice and Claire. Because you only know five people, you’re a little bit odd. You’ve designed a behavioural test for these people. The test involves a room with a spider in the middle of the floor. Each of the five people walk into the room not knowing what’s inside, and you watch happens.

Tom and Claire both screamed and ran out of the room. Sheldon and Alice walked closer to the spider and placed it under a glass. Harry stayed in the room, but did not approach the spider. From these observations you make a series of conclusions:

1. People don’t respond to spiders in the same way. There’s variation in behaviour.
2. There appears to be some kind of scale, which you might describe as: ‘reacting-to-spiders-with-a-kind-of-emotion-people-describe-as-fear-and-looks-like-fear-to-me’. For the sake of brevity you call it ‘fearfulness’.
3. Some people were more fearful than others, and vice versa.

These five people are your only reference for how people might react to spiders. You have never seen any other response to a spider. With me so far?

The Power of Prediction

Now imagine I introduce you to a whole new person: Bob. Before leaving you and Bob to get acquainted, I say “Bob is quite a scaredy cat”.

Based on your prior experience, how do you expect Bob will react to the spider room? Go on – say it out loud right now. Make a prediction.

Your scale of fearfulness that you’ve previously observed suggests that Bob is going to scream and run out of the room when he sees a spider. That’s why we use personality, that’s why we describe people as ‘fearful’, it allows us to make a prediction of their behaviour. 

Weird World Two

But this only works because we are using similar frames of reference. Imagine if Bob and I came from a world where most people went right up to the spider. In our world, Bob sits in the room, but as most people go up to the spider, or touch the spider, he’s considered fearful in relation to them.  

When I tell you “Bob is quite a scaredy cat” and you bring Bob to your test room, Bob just sits in the room quite happily. He’s not ‘fearful’ in comparison to the scale you’ve made with your five people, but he is ‘fearful’ in comparison to the scale I’ve made with  my five people. I’m right in saying he’s a scaredy cat, from my point of view, and you’d be right in saying he was brave, from your point of view. How very Jedi of us. 

As we’re talking about imaginary worlds, it’s not a case of us failing to measure everyone (in each world there are only five people, including ourselves, until I opened up a trans-dimension rift and brought Bob to yours). Bob is not being measured wrongly in either universe, it’s just that the scale itself changes from one to another.

And once we’ve brought Bob in, the scale changes again.

Predictions Without Information

Now imagine I’ve brought you another new person, Holly, but I don’t tell you anything about Holly. Based on your experiences, how do you think Holly will react to the spiders?

Well you have two people (Harry and Bob) who sit in the room with the spider. Two people (Tom and Claire) who run away. And two people (Sheldon and Alice) who put the spider under a glass. If we consider the Toms and Claires of this world to be very scared, and the Sheldon and Alices  to be very brave, then Harry and Bob are pretty average.

Failing any other information, the average of something is the best prediction you have. Now we have sort of quantified our people by saying ‘more’ or ‘less’ fearful, but we can’t really put a number on this. There’s no unit of fearfulness (though I propose if we do ever come across one, we call it the King). But we have arranged them on an ordinal scale, meaning we know that Tom is more scared than Alice, even if we can’t put a number on how much more scared Tom is than Alice.

This lack of units in personality leads us to a host of other problems, but for now accept its a scale without numbers.

Holly, without any other information to tell us otherwise, will probably behave like Harry and Bob because that’s the average of what the population does.

So do you see why our definition of the personality trait depends on the people we measure? It’s simply a way of placing one individual in the context of the whole population.

Did you get that?

I plan on writing a few more articles on personality, so let me know if you understood that one, or if it was a hopeless attempt at me explaining my favourite phenomenon. Also – let me know if you have any burning questions on the topic!