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)

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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!