Decisions, decisions!

How do we choose what to buy, and are the shops pulling on our strings?
21 December 2017

Interview with 

Philipe Bujold, University of Cambridge


shopping tags


Time for some Christmas shopping but how do we decide what to buy? And are the shops pulling on our string? Georgia Mills asked psychologist research student, Philipe Bujold, why it's so difficult to make decisions whilst shopping. 

Philipe - First of all, keep in mind that you’re taking advice from someone currently wearing Christmas lights. But yeah, it’s really hard to make a decision basically because of the way the brain is made. As opposed to a computer which can store enormous amounts of data, the brain is really powerful because it takes a lot of shortcuts and one of these shortcuts is basically that the brain will always try to represent the lowest amount of information at a time. The way it does that is by using references and these references are always from memory. And that’s a really efficient thing that the brain does because when it uses references it only has to encode a tiny difference in value.

So our brain is really good at making these tiny choices but, the issue with making these choices then becomes, as soon as you switch that reference, then your economic rationale breaks down. I have a really good example for this and how you can make choices really difficult. Think about the cinema for example. You can have let’s say a small popcorn or a large popcorn. Let’s say the small one is £3, the large one is £7. Most people in this case would go with the small popcorn because its £3 and you can probably buy two for the price of the large one. But, if you reverse the context, and add an extra choice which makes it a lot more difficult. You add a medium and let’s say the medium is £6 instead of the £7 or the £3. That makes the £7 larger one a lot more appealing. You’ve only a’ decoy’, which we call in neuroscience, and all of a sudden you’ve switched people’s preferences.

So choices are really good and you’re very good at maximising these choices in different contexts but, unfortunately, because we have so many choices and so many contexts then we aren’t that rational after all.

Georgia - I see. And I know the Christmas shops sometimes exploit this. You went Christmas shopping with fellow Naked Scientist Lewis Thomson earlier in the week so let’s hear how you guys got on…

Philipe - The brain isn’t the best computer we can think of. What it tries to do is always simplify, simplify, simplify. So it’s going to try and adapt its range when it codes values of the decisions we’re trying to make, and it’s going to try and adapt that round a central value that we build around our memories, so we call that a reference, for example.

From this reference point, your brain is going to try and compute what is gains and what is losses. What the store is going to try and push on you is this idea that you’re winning all the time and it’s going to set that from a reference. If you have a reference that’s let’s say a £2 pack of strawberries, what you can do from there is basically reduce the price and say it’s on sale, so the person feels like they’re winning because they’re spending less money, they’re keeping more money and they’re getting the strawberries in addition.

Lewis - I see the wine is on sale, shall we go and get some?

Philipe - You see, even when you know you still fall for it. Let’s go.

Lewis - We’re at the wine section now. There’s quite a lot of choice though, and I don’t know much about wine. How is my brain making this decision?

Philipe - There is a lot of choice in the grocery store at the moment and that is a big problem that people have also. That’s one of the situations where your brain is going to try and use the shortcuts that I was talking about earlier where you try and build a reference with your memories, and you try to use different markers that you can use in decisions in the past to try and make the best out of your current choice.

One of those examples would be price. Price for wine is a very very big indicator because regardless of the quality of the wine, people will tend to associate a certain value just based on the price. That’s actually been shown in a lot of neuroscience studies where if you increase the price of a wine that you’ve tested earlier, you actually see a brain signal increase in value sections of the brain. So it’s not just psychology at this point, it’s not just behaviour, you actually have a biological basis for it. What people try to do is go with the wine that’s either the second cheapest option or the second most expensive option, because you don’t want to go with either extreme, but you want to still use this reference to guide your decision. That’s one thing that grocery stores till try to do, they’ll put the average price at eye level and then everything else will be either above that or under that and you’ll use that reference to then compute your gains or your losses and make your choice.

Georgia - Why does buying things sometimes make us feel pretty good about ourselves when we’ve been shopping?

Philipe - The answer to that, contrary to popular belief, not dopamine; it’s actually what we call endorphins. Endorphins are opiates that you have in your brain that are naturally released. Think of opium, for example, it’s based from that drug, and opiates make you feel pleasure and that’s what you derive when you buy something. But, when Christmas comes, you also have the anticipation effect, and anticipation combined with dopamine, which is now its role is a lot more powerful than pleasure itself. So there’s two systems: endorphins and dopamine that regulate this pleasure and this anticipation of pleasure.

Georgia - Ah, I see. So you’re looking forward to this rush you’re going to get when you buy something?

Philipe - Exactly. And that’s what December is all about.

Chris - But Philipe, have you got all of your gifts then? This retail expert and psychologist of gift giving, have you completed the goal of gift buying?

Philipe - This is when people realise they should not listen to me. I have the advantage that I’m an immigrant. I’m from Canada, which means that, unfortunately, it’s really hard to give gifts to Canadians, but also means that it’s really good for my bank account. So, no, I have not bought things yet.

Chris - Are you saying you’re a scrooge, you’re just stingy?

Philipe - I wouldn’t say that. I would say I’m an expert on decision making.

Chris - Very good. Well I’ll try that on my wife and see how that goes down.


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