The Diderot Effect: Why We Buy Things We Don’t Need

Denis Diderot was a famous French philosopher who lived nearly his entire life in poverty. His fortune changed in 1765.

At the time, Diderot was 52 years old and his daughter was about to be married. He wanted to help pay for the wedding but couldn’t afford much due to his lack of wealth. Despite this, Diderot was well-known in Europe because he was a major writer of Encyclopédie, the defacto encyclopedia of the time.

When the Empress of Russia, Catherine the Great, heard of Diderot’s financial troubles she offered to buy his library from him for £1000 GBP, which is about £35,609.58 in 2020. This gave Diderot the money he needed to pay for his daughter’s wedding. He even had a bit of money left over, with which he bought himself a new scarlet robe.

That’s when everything went wrong for him.

The Diderot Effect

Diderot’s new robe was beautiful. He was never able to afford such a robe himself before, so this was quite the stroke of good fortune. In fact, it looked so good that he immediately noticed how out of place it looked when put next to the rest of his clothes and “commoner” possessions. Diderot felt the urge to upgrade his home to match his new fancy robe.

“No more coordination, no more unity, no more beauty!”
— Denis Diderot

He bought a new rug from Damascus to replace his old one. He upgraded his kitchen table and decorated his home with extravagant sculptures and statues. His uncomfortable straw chair was replaced by a new top-of-the-line leather chair. Diderot's purchases spiraled out of control!

What happened here?

Before receiving the large payment from the Russian Empress, Diderot would have never bought such a fancy rug, or extravagant sculptures, or upgraded to a leather chair. His purchases were completely reactive, a direct result of emotions caused by his new wealth.

Such reactive purchases have become known as the Diderot Effect.

Why We Buy Things We Don’t Need

Many of us have fallen victim to the Diderot effect — I know I certainly have. Every time I buy a new shirt I feel like I need a new pair of pants to go with it. If I have a new shirt and pants, well might as well throw in the jacket. And if I have all of those, I mean I definitely need to upgrade my shoes!

The Diderot Effect Spiral
The Diderot Effect Spiral

This spiral of consumption can happen with anything:

  • With a new phone, you might get new headphones or a new charger even if you have ones that work perfectly fine already
  • A new car and you feel like you need a car charger for your cell phone, a tire pressure gauge, and an emergency flashlight
  • Get a new pan for cooking and now, for some reason, you feel like you need a new spatula — oh and might as well grab a new salt shaker while you’re at it

Did you really need all of those other things? Getting a gym membership doesn’t necessarily mean you need a personal trainer and a foam roller and knee sleeves. A new shirt doesn’t mean you need matching shoes.

We have a natural tendency to make sure our lives are full. We are never looking to downgrade or reduce what we have, quite the opposite in fact.

As soon as we get something new, we have our eyes set on the next thing. And if we upgrade one part of our lives, we’re very much inclined to upgrade all of the other parts to maintain a consistency.

“The purchase of a new home is the impetus for replacing old furniture; a new jacket makes little sense without the right skirt to match; an upgrade in china can’t really be enjoyed without a corresponding upgrade in glassware. This need for unity and conformity in our lifestyle choices is part of what keeps the consumer escalator moving ever upward.”
— Juliet Schor

How to Overcome Spiralling Consumption

We’ve learned about the Diderot Effect and how things can spiral out of control. Now it’s time to grab the steering wheel again and get ourselves back on track.

While constant upgrading and ascending consumption are our natural inclinations, we don’t have to follow those paths. We can take a more conscious and healthier approach.

Reduce exposure

Most of the actions we take are triggered by subconscious habit.

For example, we’re quick to buy things on sale, somehow feeling that because it’s on sale we HAVE to buy it now. The trick is of course that we might have never bought that thing if it wasn’t on sale — it’s the psychological trigger that the item is on sale that go us interested.

One of the quickest ways to reduce the power of the Diderot Effect is to reduce the occurrence of those triggers in your daily life.

  • Unsubscribe from commercial emails that send you the latest deal
  • Throw away those useless catalog magazines that come in the mail
  • Hang out with your friends in places where you won't see advertisments, such as the park or one of your homes

In general, reduce the amount of exposure you have to advertising and people trying to sell you things.

Automate to optimize

It’s hard to limit your spending at the mall or online shopping if every time you get a paycheck your money is sitting right there, just waiting to be spent.

Instead, you can automate a portion of your paychecks to go straight to a savings or investment accounts. Plenty of banks offer this kind of service. With the spending money out of sight (and put in a better place), it’ll be a lot easier to control your spending.

Ask yourself

One trick I like to use is to go through a quick personal survey every time I’m about to buy something:

  • Do I have anything else like this or that serves the same purpose?
  • If I buy this, what else will I not be able to buy after I’ve spent the money? (since now I have less money to spend on other things)
  • Do I actually need this? Or do I just want it? How much will it actually benefit me?
  • If I do need this item, can I get it at a cheaper price or borrow it from someone?

It’s a short survey that helps tremendously in avoiding buying things I don’t need. Usually, the answer to at least one of those questions stops me from buying.

Break from buying

Take a break for one month from buying anything new. No new clothes, tech stuff, equipment, or anything you’d classify as things.

Then take a break for two months. After that, three months.

Pretty soon, you’ll see that you didn’t need those new things after all. All it took was time.

Less Consumption, More Satisfaction

Our natural tendency is to consume more, to fill up space, and make sure everything fits. But this spiralling consumption leaves us dissatisfied as we’re always looking for the next best thing, rather than being content with what we currently have.

Life doesn’t have to be that way. You don’t have to constantly consume. Instead, you can optimize your life, filling it only with what makes you truly more productive, fulfilled, and happy.

“The secret of happiness, you see, is not found in seeking more, but in developing the capacity to enjoy less.”
— Socrates

For more reading related to the Diderot Effect and how to form good habits, here are a couple of books:

The Overspent American by Juliet Schor

Atomic Habits by James Clear

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