In this video we consider why traits might differ between people, beginning with the possible role of biological systems. Hans Eysenck suggested that introverts and extraverts differed in their levels of cortical arousal, resulting in different needs for stimulation that influence behavior. Next we look at the behavioral approach system and the behavioral inhibition system, two opposing systems of brain activity which roughly correspond to positive and negative emotion. Differences in activity and responsiveness of these two systems may explain some personality differences.
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Video Transcript
Hi I’m Michael Corayer and this is Psych Exam Review. In the previous video I talked about the idea that a trait-based approach to personality is useful for describing the ways that people differ but it’s not as useful for thinking about what might be causing those differences. So we might be able to observe that people differ in their level of agreeableness and that might be associated with a number of other things, but we still don’t know why people differ in their level of agreeableness. We might wonder if it has something to do with their biology; maybe it’s hormones or neurotransmitters that are influencing this. Or maybe it has to do with their past and their upbringing; maybe previous rewards and punishments have shaped their behavior and that’s responsible for the difference that we see for this particular trait. Or maybe it’s the way that they think about the world. Maybe it’s, you know, the way that they process information; the way that they make decisions the schema that they have. Maybe these are the things that are causing this difference in agreeableness or some other trait.
So in this video we’re going to start looking at what might be causing trait differences between people and we’ll start with a biological approach to thinking about this. And this first example comes from Hans Eysenck, who you might recall initially proposed a 2-dimension way of thinking about personality, just looking at extraversion and neuroticism. Now when it came to explaining why people differed in extraversion, Eysenck proposed that it had to do with their level of cortical arousal. And this is actually a little bit counterintuitive because what he suggested was that people who are introverted actually had higher levels of cortical arousal.
Now you might not expect that initially, but the idea is that they already have a high level of activity and so they don’t need to seek out additional stimulation from the environment. So the idea is that there’s some optimal level of cortical arousal that a person wants to have, and if they’re introverted they’re kind of already at that optimal level. So they don’t need more stimulation from the environment. Whereas somebody who’s more extroverted is at a lower level initially in cortical arousal and as a result they’re motivated to get out into the environment and get more stimulation from other people. And so he thought this could explain differences in this trait.
And we can also see this in things like the fact introverts tend to be better at vigilance tasks. So the idea here is vigilance tasks are fairly boring, you know, you’re staring at a screen, you’re maybe waiting for a light to turn on. That is, if you’re already at your optimal level of cortical arousal then you’re better able to be focused on this particular task. But if you’re at a lower level of cortical arousal, this is going to be very boring for you and you’re gonna want more stimulation from the environment and you’re not gonna be getting it during this task. So you might be more distracted, you might not perform as well.
Now we also see a difference in drug use. So people who are introverted tend to use stimulants less. Now this makes sense if we think about them already being at their high level of cortical arousal, because they actually don’t want to be over-stimulated. If they were to take stimulant drugs, it’s going to push them up even higher and they’re going to be over-stimulated. On the other hand, we see that people who are introverted are more likely to use depressant drugs than people who are extroverted. And again this makes sense in terms of cortical arousal, because let’s imagine that person’s already sort of at their optimal level and then you put them in a very stimulating social environment like at a party. What you might find is they’re over-stimulated, so they’re going to seek out something that’s going to reduce their cortical arousal and depressant drugs would do that. So they might be more likely to drink alcohol to try to inhibit some functioning and bring their cortical arousal back down to a more manageable level.
Now another way that we can think about biological differences between people is to look at two systems and the first of these is the behavioral approach system. This refers to a system that uses pathways that use the neurotransmitter dopamine and it’s really about the response to incentives and rewards, right? This is forcing you to approach situations; it’s sort of pushing you out into the world and it’s associated with higher levels of activity in the left prefrontal cortex. So you can kind of think of this as the positive emotion system, right? It’s pushing you out to experience rewards; to have, you know, incentives of motivating you to seek things out in order to get more positive emotion.
And we also have an opposing system and this is the behavioral inhibition system. And so this is a system that uses pathways that use the neurotransmitters serotonin and GABA, which are inhibitory neurotransmitters and this system is more about the response to punishments; anxiety, aversion, disgust, fear, right? It’s inhibition, it’s withdrawal, right? It’s pulling you back and it’s more associated with negative emotions and it’s also associated with higher levels of activity in the right prefrontal cortex.
So we sort of have these two systems opposing each other and one way that this is described by Jordan Peterson, who has a number of excellent personality lectures available on YouTube which I’ll link to in the video description, is to think about how people confront the unknown right or the chaos of the world. On the one hand, you want to be motivated to get out there; to approach the unknown, right? Because that’s where the rewards are. So you know he describes that’s going to the Dragon’s Den because that’s where the gold is, right? So you have this great potential in the unknown, potential for reward.
On the other hand, you need to be a little bit hesitant. You can’t just rush out into every new situation because things are dangerous and the dragon can kill you. So you also want to have a system that’s inhibiting your behaviors; it’s making you a little more cautious, right? That’s using negative emotion in order to restrain the positive emotion of the reward system. So we can think about these two opposing systems in this way; as how people confront the unknown and you don’t want to have one of the systems be so much stronger than the other, right? You don’t want to have this situation where they’re inhibiting all behavior, right? This is someone with agoraphobia, right, who like won’t leave the house because every situation is, you know, anxiety provoking and is all about punishments and fear, right? And that would be sort of this over-activation of this behavioral inhibition system.
So to bring this back to personality differences, we might think about the ways that individuals can differ in terms of the activity of these two systems, and in their responsiveness. So by that I mean a certain situation might provoke a greater response in somebody’s inhibition system and that’s going to influence their behavior and another person might have a different response to that same situation. And so they’ll have a different behavior, and this will give us sort of the differences that we see in personality.
Now you might say that talking about these systems here is avoiding the question that started this video; what causes trait differences? Because we may say well we have these two systems but what’s causing differences in these systems? Why is it that people would have different levels of activity or different levels of responsiveness? And you might wonder, you know, is it genes that are sort of programming these two systems? Or do people have the ability to change these systems? Can they transform their ways of dealing with the unknown? Can they change their levels of emotionality to certain situations? And that’s something that we’ll consider in a future video. So I hope you found this helpful, if so, please like the video and subscribe to the channel for more. Thanks for watching!
