Diderot Never Bought the Dressing Gown

On 9 September Apple announced its first foldable iPhone, the iPhone Duo, from £1,999. apple-iphone-duo The same announcement priced the room around it: a £79 case, a £129 folio with a kickstand, and support for Apple Pencil. Nobody can order the phone until 16 October. The set it belongs to was laid out before anyone had held it.

I know where this goes, because I did it with a camera. Canon announced the EOS M50 in February 2018 at £539.99 for the body. camera-jabber-m50 I bought one and told myself it was the cheap way into proper photography. Then I searched YouTube for one simple thing about it, and it ended up costing me five times its price. I have taken far fewer pictures than I planned. The usual name for this is the Diderot effect, and the usual moral is to buy less. I think that moral is aimed at the wrong moment. The purchase did not start my spiral. Being shown the finished set did, and the set I was shown had no last piece.

The Gown Was a Present

The effect is named after an essay Denis Diderot circulated in February 1769. bibliorare-diderot-1769 In it he mourns an old dressing gown, replaced by a scarlet one. The new gown was so fine that his straw chair, wooden table and unframed prints had to go. diderot-regrets-abidor The popular retelling has him flush with money and shopping. James Clear's widely read version says he "acquired" the robe. A footnote admits he could find no source for a gift. clear-diderot-effect

The source exists. A translator's note in PN Review records that Madame Geoffrin, a wealthy patron, sent the gown with pictures and furniture. It was her thanks for his help with an inheritance. bamforth-pn-review Diderot did go on to buy: he admits to sketches, and to debts. But the thing that started it was given, and somebody else furnished the room around it. Hold on to that, because I think it is the mechanism.

Why Does Wanting Things to Match Usually Save You Money?

Grant McCracken, the anthropologist who named the effect, published it in his 1988 book Culture and Consumption. mccracken-culture-consumption He defined it as a force that keeps our possessions consistent with one another. In its ordinary working it holds us inside the set we already own. Someone fully governed by it, he wrote, resists even skilful attempts to sell them something new.

So the buy-less sermon points the instinct the wrong way round, and I think it suits whoever furnishes the room. McCracken's account is of a guard that sometimes fails. The guard protects us from gifts that carry new meanings, he notes, and he calls the gown a present. When it fails badly he describes a spiral: each purchase sets a standard the next one rejects. Diderot escaped that. He kept one worn rug, and declared that "the poison has not yet acted".

Who Shows You the Finished Room Now?

Diderot needed a rich friend to show him a finished room. I needed one search. Anyone wanting a Duo was shown the room in the announcement, five weeks before the phone could be ordered. In January 2018, weeks before the M50 was announced, YouTube's product chief said recommendations drove more than 70 per cent of viewing time. cnet-youtube-mohan My feed became the camera: rigs, cages, bag tours, and the case for the Sony I had not bought. That the feed caused my spending is my inference. One man's bank statement proves nothing about a system.

What I can say is how such rooms are built. I argued in Why Your Suggestions Never Run Out that a suggestion feed treats an empty state as a bug. And in October 2017 four researchers, three of them at Harvard Business School, named a neighbouring trick: pseudo-set framing. barasz-pseudo-set-framing Group items arbitrarily so they look like a set, and people work to complete it. They persisted when it cost them, and after they were told the set was arbitrary.

Five Times the Price

I bought the list. A SmallRig cage, ND filters, lens kits, a cold shoe mount, memory cards, and every lens attachment sold as an add-on. I did not choose among them, and choosing is what clients pay me for. Even then something always seemed missing, or newly out of date.

Here is what I would prefer to leave out. I watched the videos: the comparisons, and the reaction videos I call horrid. And I build these rooms. In 2020 I consulted on a crypto newsfeed app whose timeline loaded forever, and I have handed off wireframes that removed the last visible stop. I said so in Infinite Scroll Is a Cognitive Weapon of Mass Destruction. Whoever opened that app for one headline met a room I had helped furnish. In October 2023 Canon discontinued the system, so the maker abandoned the set I was still completing. petapixel-eos-m

The Bite on Your Ankle

You know the mosquito bite you find on your ankle at night. Scratching is the only thing that helps, and for a few seconds it helps completely. Then the itch comes back wider, and your hand is already moving. Each accessory was a scratch. It quietened the feeling that something was missing, and it made the patch bigger.

Novelty Wears Off, and the Average Buyer Stops

Novelty wears off, and that alone explains the feeling that something is missing. Shane Frederick and George Loewenstein reviewed the evidence in 1999: people adapt to what they gain, and the pleasure fades. frederick-loewenstein-1999 No feed is needed for that. Nor does the feed catch the average buyer. In 2018 the Japanese camera makers shipped 1.6 to 1.7 lenses for every interchangeable-lens body. cipa-2018-shipments That averages out at a kit lens and not quite one more. The accessories are real tools, too: without an ND filter you cannot hold a slow shutter in bright sun. On this account ecosystems are innocent, I lacked restraint, and this essay is an expensive excuse.

Most of that stands, and I chose every item. Adaptation explains why each purchase faded, and leaves open why I had no idea of enough. Robert Wicklund and Peter Gollwitzer offered a reason in Basic and Applied Social Psychology in 1981. wicklund-gollwitzer-1981 People committed to an identity they have not yet earned, they found, reach for substitute symbols of it. Their subjects talked themselves up; that mine was shopping is my extension. I had bought the camera to become a photographer, and a feed can sell symbols to that ambition for ever.

The Rug

Diderot was shown a finished room once, by a friend, and the buying stopped. I was shown an unfinished one every morning, by the kind of interface I design, and paid five times over to keep up. He kept a worn rug to remember himself by, and I have a camera still waiting for its photographs.