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In true Pavlovian form, humans are accustomed to getting excited at the sweet sound of an ATM dispensing cash. But is that sound artificially generated? If so, why?

The website Humans Invent, which is somehow partnered up with Sharp Electronics, posted a roundup of technologies equipped with artificial sounds “designed to help humans.” Ultra-quiet electric vehicles, for instance, are being outfitted to produce “vroom” sounds so that pedestrians and bikes can hear them coming and get out of the way, if need be. Some sports arenas have artificial crowd noises, and while those sounds are designed to help the home team, they mostly serve as reminders (depressing, sorta creepy reminders) that the arena is three-quarters empty.

The last item in the list is the ATM machine, with its “comforting whirr of the cash point,” as Humans Invent puts it:

The assumption most people jump to is that the sound is produced by rollers delivering the notes to the collection slot. In fact, the sound is an entirely artificial addition to the process. The noise is produced by a speaker and purely included in the transaction to reassure you that your money is on its way. Without the added noise, the ATM would be practically silent with its moving parts on the other side of a brick wall.

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Word of these claims quickly spread online, and in a thread at Reddit, several commenters who say they’ve worked on ATMs for years called B.S. One wrote:

I serviced ATM/ABM machines for over 4 years, there is no artificial sound, the machines really are that loud (and about 10 times louder with the vault door opened) the belts that are spinning to deliver the cash from the cash cassettes to the customer are by no means “practically silent.” And there is no f***in brick wall in the MIDDLE of the damn machines.

Humans Invent countered by pointing to a Times (of London) story about artificial electric car sounds that quickly and offhandedly also mentions a few other purportedly fake features added to various technologies over the years:

• An unpleasant odour has been added to natural gas since 300 children died in 1937 after a leak at a Texas school went unnoticed

• Digital cameras make the sound of a shutter closing to reassure users

• Cash machines whirr to convince us that our money is on its way

• Manufacturers use dye to make strawberry ice-cream pink, ketchup red and squash orange

If the cash-machine sounds are fake, you can understand why designers would make them so. As the great philosopher Jerry Seinfeld once mused: