Waiting for the penny to drop

“I’m waiting for the penny to drop”.

This is a British idiom, not related to the American idiom about “the other shoe”. It is what you might say if you have just told somebody something, and it’s clear from the expression on their face that they haven’t grasped the implications of what they’ve heard. It might be obvious puzzlement, or it might just be the absence of whatever reaction would be most natural, whether joy or anger or outright terror. When the point of what you’ve just said “sinks in” (to use a different metaphor), they might confess “The penny’s just dropped”, or you may be able to see it for yourself.

I’ve seen online explanations, but these are usually missing one vital detail, presumably because the explainers were not on the scene when that detail was obvious. This is an attempt to get that detail on the record before it disappears from living memory.

It is rightly explained in terms of old-fashioned coin-using machines, which depended on mechanics rather than electronics. I’m going to use the example of the simple chocolate-vending machines which used to be found on railway stations, because that’s the kind I knew best.

The mechanism was fairly simple to understand, even from the outside. The bars of Cadbury’s chocolate would be stacked vertically in a metal case. There was a coin-slot at the top of the case and a drawer at the bottom. The customer would drop his penny in the slot and it would fall to the bottom of the compartment, where it would press a lever. The lever would open a little door underneath the stack and one bar would drop into the drawer. The customer would then pull out the drawer and claim the contents.

As often happens, the weak point in the mechanism was the human element. Everything went fine as long as these events came in the right sequence. Too frequently, though, the customer would be impatient, and would pull out the drawer before the chocolate had finished dropping, or even before the chocolate had started dropping. In the first case, the bar would jam the drawer so that it could not be fully opened, and in the rare second case it would be jammed behind the drawer. Either way the customer would get no chocolate. Neither would anybody else for the next six months, because there was nobody on the station responsible for unjamming the machines , though they would still treacherously take your money.

Obviously customers would be well-advised to be more patient and allow more time. The vital detail I mentioned is that this advice had become necessary enough to be clearly printed in a notice on the machine itself, and the wording of that notice was;
“WAIT FOR THE PENNY TO DROP”
Admittedly, by the time I was travelling around England being interviewed for universities, the impact of inflation had enforced a change in wording, to the more flexible;
“WAIT FOR THE COIN TO DROP”
But by that time the original version was already proverbial.

So the popular remark is a metaphor. Observers are waiting for the information received to travel, like the original coin, from one end of the receiver’s brain to the other, where it will take effect and produce a reaction. The vital detail missing from most explanations is that the wording of the popular remark has been directly borrowed from the wording which Cadbury’s customers would see in front of them (and that was why it came into use in that form).

Perhaps somebody would be good enough to inform Wikipedia.

a reply to: DISRAELI

If this only happened to the brainwashed 'lefties/democrats'.

a reply to: DISRAELI

While I am not in England, I have watched many British comedies and shows. I think you have it wrong.

I believe it is related to the expression "I need to go spend a penny" or just "spend a penny". Back in the past, public loos were of the kind that you had to pay a penny to unlock the door before entering for relief. The expression "wait for the penny to drop" I think is to wait for the previous customer to rotate the mechanism from inside to allow you your turn. This would allow the penny to fall from the lock releace mechanism to the holding bin.

Also, "waiting for the penny to drop" would also mean a restroom attendant would listen to hear the penny drop before someone exited. If no penny dropped, the customer had cheated the system by entering when the door was opened by the previous customer therefore there was no penny drop. The attendant would deal with the situation as they were paid from these pennies.

I could be wrong. It is interesting when translating from English to English and even English as there are many subtle differences.

a reply to: DISRAELI

a reply to: beyondknowledge2
I've also used those "public convenience" mechanisms in the days when they still took pennies, but my memory is that the penny "dropped" on entrance and released the door-lock. The need for the next person to "wait" for it wasn't happening. The locking of the door by turning a handle from the inside automatically moved an external sign to "engaged", and that's what warned other people not to try entering.

You are relying too much on the coincidence of the word "penny", and the truth is that in the days before inflation a single penny was enough to cover all sorts of needs, and so the word appeared in many contexts. Small boys trying to raise funds for fireworks before Bonfire Night would create a "Guy Fawkes" effigy and put it on display with the cry "Penny for the guy!". My grandnother remembered icecream being sold under the slogan "Hokey-pokey, penny a lump!". According to an old rhyme, hot=cross buns used te be "one a penny, two a penny". Even I remember when a penny was enough to buy two gob-stoppers, which was useful when you were allowed exactly one shilling to spend on sweets.

I know I'm not wrong, because I remember seeing the notice mentioned at the end of the OP.

a reply to: visitedbythem
Thank you for that picture.

Those machines are a somewhat later model than the period I was talking about. One clue is that they look much smarter than the ones I remember, which were blue and weather-beaten. The knob which has to be turned is a new level of sophistication, an improvement on the old design. But the real proof is that they are priced in decimal currency ("20p"), which replaced the older currency in 1971. So they are later than 1971 and "how much later" is an interesting question. It depends on the rate of inflation. In 1969 I was probably offering a shilling for the smaller, more basic bars. "20p" is the equivalent of four shillings, so time has to be allowed for the price to rise to that extent. My guess is not earlier than 1980.

That explains why the wording got changed, as part of a more modernised design, and trying to get away from the proverbial cliche. The 1969 models were still using "wait for".

P.S. "Coins", together with the price and the size of the coin-slot, implies that they were taking two 10p coins, so the internal mechanism would also have to be more sophisticated.