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Comment by mschwaig | Hacker News Reader

A similar thing happens at an ATM when you dispense money before you give the user their card back. They tend to forget the card more often. Apparently this happens because the users goal in that whole process is to get the money, not to get the card back. So as soon as they have their money the forget about the card. Since the user has reached their goal there is no reason not to forget about the state of the task.

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That's an interesting take on it. I'd always thought it was because: when ATMs were first introduced, people thought of the cash as more important than the card... Nowadays, I'd say the reverse is true for most people: I've occasionally started to walk away from the machine, stuffing my card into my wallet, only to be drawn back by the whirring sound of the cash counter... People are too set in their ways to reverse it now, but perhaps they could give us both cash and card at the same time?

Giving people their cash and card at the same time would open them up to a scenario where an attacker can just grab whichever they don't reach for first.

You could give them on top of each other so that both can be grabbed simultaneously.

From working a few different jobs in retail, I can say it is not to uncommon for people to walk away after paying, leaving their just-purchased items behind.

That's known as a "post-completion error" - you've finished what you meant to do, like making a photocopy, and then forget to do some follow-up step, like take the original document off the copier.

A similar thing happens in casinos.

A person sits down to play a slot machine but then they turn to their friend to say something. When they turn back to face the slot machine "Where is my money! I put money into it!"

They didn't put any in a review of surveillance video shows they didn't. The customer then looks in the envelope they carry thei cash in and see their money is there.

Most ATMs now in my experience scan & return your card to you at the beginning of the transaction, so you don't forget it in with all the other details.

Mine is somewhat the opposite way - my goal is to ensure I get the card back and then forget about the money :(

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