The Representativeness Heuristic

In this video I describe another heuristic identified by the work of Amos Tversky and Daniel Kahneman. The representativeness heuristic is a shortcut that we use when attempting to estimate the odds of something being true, such as whether an interview profile came from a lawyer or an engineer. Rather than using relevant base rate information, participants showed a tendency to rely on prototypes when making this decision.

 

Daniel Kahneman – Thinking, Fast and Slow (Amazon) http://amzn.to/2nAWnop

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Video Transcript:

Hi I’m Michael Corayer and this is Psych Exam Review. In this video we’re going to look at another example of a heuristic identified by the work of Amos Tversky and Daniel Kahneman.

So for this I’d like you to imagine a hypothetical situation. Here I want you to imagine that I have conducted 100 interviews with 70 engineers and 30 lawyers and what I’m going to do is I’m going to mix up all of these assessments and I’m going to randomly pull out a profile and read this person’s profile to you. Your job is to guess what are the odds you think this person is a lawyer or an engineer.

Ok, so we’ll start with, let’s imagine I pull out the profile of a man named Adam and I tell you that Adam seemed to be outgoing, he was interested in politics, and he displayed particular skill in argument. So what do you think about Adam? What are the odds Adam is a lawyer or an engineer?

Ok, let’s look at another profile. Let’s imagine I pull out a profile of Dick here. It says Dick is a thirty year old man. He’s married with no children, he’s shown high ability and motivation, and has been quite successful in his field, and he’s well-liked by his colleagues. So what do you think about Dick? What are the odds Dick is a lawyer or an engineer?

So if you were thinking about these people here and you thought Adam was probably a lawyer and you thought Dick was a little harder, you might have said, you know, “I couldn’t really tell, 50/50 chance. I mean he could be a lawyer, he could be an engineer, I really don’t know”. Well if you thought this way, which is how most of the participants in Tversky and Kahneman’s study thought, then you’ve demonstrated this representativeness heuristic.

So why is that? Well what you’re doing if you thought this way is you’re comparing to your prototypes of what you think an engineer or a lawyer is, right? You’re trying to decide which category to put this person in and so you compare them to sort of a mental prototype of what is a lawyer or what is an engineer. If you were thinking this way when trying to figure out whether Adam or Dick was a lawyer or an engineer, you were doing it wrong.

there’s a much better way to determine this because what you were ignoring is the base rate information. All right, I actually told you at the start the odds that either one of them is a lawyer or an engineer, right? I told you there were down right here. You probably didn’t include that in your analysis of each profile right? If you include that, you would just say engineer every time, right? for Dick, “well 50/50 chance” and that’s actually what many participants said. It’s an equal chance of lawyer or engineer.

Well, no 70/30, I mean he’s probably an engineer and even with the case for Adam, you know, I told you he’s interested in politics and skilled in argument. That was to sort of prime your prototype of what you might associate with lawyers. But of course there are engineers who are interested in politics and there are engineers who are good at argument and so, you know, the odds are still very much in favor of engineer even though he sounds like a lawyer.

Ok, so what’s happening here? In the availability heuristic, remember, we said that our mind substituted. It substitutes a different question. We’re not good at estimating frequency and so what we do is we just see how easily does it come to mind, right? And we answer that question instead. So what’s the question here that triggers this representativeness heuristic and what question do we do we replace it with?

Well the idea is we’re not good at calculating odds. We don’t like doing probability; our minds are really not equipped to do this. So whenever we ask this question, as I was doing here, which is “what are the odds of something, what are the odds of X?”, you know, in this case it was “what are the odds this person is a lawyer?”. Well as soon as we start thinking about this our mind says, “you know what I’m not doing odds. There’s probability, these calculations and statistics, it’s very very complicated, let’s not try to actually do all of that. That’s going to take a long time and, you know, I don’t have the time to do that. Instead let’s take a shortcut. Let’s answer a different question.”

So the shortcut is to say “how well does this match my prototype?”. Now here’s a question that we can answer. How well does this match my prototype of that. So instead of “what are the odds of this, this person is a lawyer” say well “how well does this person match my prototype of a lawyer?”. There’s a question that we can answer.

We can say “Oh Adam, he sounds like a lawyer, you know, he fits my profile, my prototype fits, my sort of stereotypes about what a lawyer is or what an engineer is”. So the idea is well if it matches my prototype then I’ll say that the odds are high and if it doesn’t match my prototype I’ll say that the odds are low.

Of course we can think about other situations beyond this hypothetical here where this is a real problem. We don’t want to just be making decisions based on how well things match our prototype. I mean imagine that you were interviewing for a job and maybe what’s really happening is it’s just a matter of seeing how well you match the prototype of the interviewer for this particular position. Well what’s my prototype of this position and does this person match? Ok, they seem to match, give them the job, right?

We don’t want that sort of thing happening and it’s even worse if you think about other situations. I mean, what are the odds this person is a criminal? What are the odds this person is a terrorist? Here we can see why things like racial profiling occur because what happens is that’s a really hard question to answer.

What are the odds that this person is a terrorist? How do we go about doing that? How well does this person match my prototype of a terrorist, in other words, how well do they match the stereotypes that I have about what, you know, who terrorists are? Of course that’s not a very fair way of trying to answer this question, right? We’re going to ignore other potentially relevant information when we’re comparing to a prototype so there’s a danger to this representativeness heuristic and how it can lead us to make errors that can have important consequences.

Ok, so that’s this representativeness heuristic; the idea that we make comparisons to prototypes rather than actually looking at the base rates of things and actually trying to figure out the odds of something occurring. I hope you found this helpful, if so, please like the video and subscribe to the channel for more. Thanks for watching!

Category Recognition

In this video I consider how language can help us to organize thought and create more precise concepts and categories. This raises the question of how we recognize new stimuli as being part of a particular category. Protoype theory suggests that we mentally compare new stimuli to a prototype or most-typical example for a particular category. Exemplar theory suggests that we use prototypes in addition to our memory for other examples of exceptions and variations, though this process will be slower.

 

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Video Transcript:

Hi, I’m Michael Corayer and this is Psych Exam Review. In the previous video I talked about this complex relationship between language and thought.

In this video I want to provide one way of thinking about this relationship in that language helps us to organize our thought. It helps us to create more precise concepts and categories to make sense of the world. Of course animals can also create concepts and categories without using language and we saw this in the video on abstract learning I talked about pigeons who were taught to peck at pictures of chairs and then they could be shown a new picture of a chair that they’ve never seen before and they would correctly peck at it.

This shows that they have some understanding of this idea of the category of chairs. Now this makes sense that animals should be able to do this without using language, after all, they need to be able to recognize new stimuli that they’ve never seen before. They need to be able to see a new item of food that they’ve never seen before and recognize that it’s food or they need to see a predator and recognize that it’s a predator even though it’s not a particular predator that they’ve seen before.

Ok so how do we go about deciding when something is part of a particular category? How do we recognize something as being a chair? How is it that we can walk into IKEA, see a chair that we’ve never seen before, and immediately know that it’s a chair.

Well, one way of thinking about this is we can say, well maybe we have rules that we follow. Maybe we could come up with a list of rules of chairness. Ok, if it’s a chair then it will meet these criteria. This seems reasonable. The problem we have is that it’s hard to figure out what those rules would be. As soon as you come up with a rule you can probably think of an exception to it that you would still recognize as a chair. You might say, okay, well it has to have four legs. Well you know that’s not necessarily true. I mean it could have a solid base and I would still recognize it. Ok, well you know does it have to have a hard or soft surface? Well that doesn’t matter, it could have either. Or sharp or rounded corners? Well that doesn’t really matter either.

What you find is that it’s really hard to come up with a list of rules of chairness.. So we probably aren’t using rules when it comes to recognizing parts of a category. Instead we’re probably using some general guidelines where we have some features that we recognize as being important for a particular category but we also recognize that there’s exceptions and there’s variation.

To demonstrate this, I’d like you to draw a picture of a bird. So pause the video for a few seconds and just quickly sketch a bird. All right now I’m going to draw a picture of a bird and we’ll see if my drawing is similar to what you came up with. So if somebody asked me to draw a bird I would probably draw something like this.

Ok, so here’s my bird. Not a great bird but it’s enough of a bird I guess and maybe this is similar to what you’ve drawn. Hopefully it is and so what I’ve tried to show is I’ve tried to draw a prototype of a bird. A prototype refers to something that’s sort of the best example of a bird, right? It’s the most bird-like bird that I could draw, right? And so the idea here is that it has sort of all of the characteristic features that we associate with this category of bird.

Now you probably drew something similar to this. You probably didn’t draw a penguin or an ostrich. Now those are just as much birds as the bird that I’ve drawn but they’re not as prototypical. They have a lot of features that don’t quite fit with the general idea of what a bird is.

So what prototype theory suggests is that when we see a new stimulus we compare it to a prototype to determine if it’s part of a category. And again, the prototype is this idea of the most typical example. Ok, so when I see some new thing that might be a bird I mentally compare it to something like this; something small, has feathers, can fly, has twig-like legs, a small beak, right? These are the things I associate as being sort of prototypical bird features and something to compare a new stimulus to those in order to identify it.

Now this idea of how we recognize parts of a category, we can see in children when they do this. We can see, you know, if a child is taught this is a doggy right? Ok, doggy and then later they see a cat and they say doggy. Well what’s happening there? What’s happening is they’re actually correct, I mean those things are part of the same category if you think of that category as being small furry things that you can play with and pet.

In that case they are part of the same category and then what we have to teach the child is well actually you know linguistically we have some different labels for those. We divide them up into sort of a more precise version of that. We say okay well these ones are dogs and these ones are cats. Yes we can put them overall in the category of pets but we’re going to be more specific here and doggy refers specifically to these types here and cat refers to these types here.

But in terms of recognizing the category of this new item the child is actually pretty much correct in thinking of doggy as being these small furry things that you play with. Ok so how do we go about recognizing something that’s different from a prototype, right?

So sometimes the idea of prototype theory is that you know we’re going to bring something to mind and compare it to this prototype and recognize whether it’s part of a category or not. But of course the exceptions are also recognized. So how does this happen?

This brings us to what’s called exemplar theory. What exemplar theory says is that we have prototypes that we mentally compare to but that we also have our memory and we can also bring to mind other exceptions that we’ve encountered. So we can, you know, if we want to recognize whether some new stimulus is a bird or not, we compare it to a prototype of a bird but we might also consider how it compares to a penguin or an ostrich or a peacock, right? We can bring to mind our memory for exceptions and those will help us in making this determination.

The problem is this is going to be a little bit slower right? When something is closely matched to a prototype we can see it and recognize it immediately. When something has more exceptions and needs to be thought of in terms of other variations then that’s necessarily going to be a slower process. It’s going to take us a little bit longer to decide if something is part of this category.

Ok, so that’s prototype theory and exemplar theory, I hope you found this helpful, if so, please like the video and subscribe to the channel for more.

Thanks for watching!