Where did the visual shorthand of licking lips for food come from?

Visual Shorthand, cue, cliché, whatever - you can Google-image licking lips food and find many images from cartoons, ads, clip-art etc. of people licking their lips in anticipation of eating. It’s common enough in old school advertising, and persists in today’s clip-art (example).

But in reality, I nor anyone I’ve know (admittedly somewhat less than 7 billion people) have done so except in a comic manner. Nervous tics, to wet dry lips, to clear smears of pasta sauce on their lips, yes I’ve seen people licking their lips, but just looking at food they haven’t tasted yet? Nope, and on the face of it doesn’t seem to make a lot of sense.

So where did this common image come from? Different cultures? Pets? Out of the blue in a long distant past? Where?

Sadly for the purposes of this thread, searching for licking lips on this board brings up many posts related to licking and a lady’s other set of lips…

I’ve seen not only humans but animals do it. It apparently is so universal it predates our evolution.

People (and animals) salivate at the prospect of food. Licking the lips is a response to salivating ('cause if you don’t, it becomes “drooling.”)

Ask Pavlov’s dogs.

Licking the lips will not prevent drooling. Swallowing the saliva will.

Do you have evidence that they licked their lips a the bell? They produced more saliva and digestive juices, but Pavlov knew that because he has a tube surgically implanted in the dogs to collect and measure the excess liquids.

NJTT’s resonse agrees with what I thought when I posted the OP - yes, people who see appetizing food may salivate a bit more, but I don’t think they’ll start drooling almost cartoon like, necessating the licking of lips.

As for animals, well, we only had 2 dogs as pets, so the sample size is small, but they would often lick their lips, food or not. Other animals, perhaps related to lapping water?

You’d figure some institution had to have done studies on this (why not, most everything else has been studied.), Remember, I mean real involuntary lip-licking in humans at the sight of appetizing food, not meant in an comedic or ironic fashion mimicking some cartoon or clip-art, nor other reasons such as dry or irritated lips, nervous tics, and so on.

Sadly, this visual cue seems to irk me more than it really should…

When I’m eating a bowl of cereal, and my cat jumps up on my lap and stares at me, she licks her chops to let me know it’s not love. She wants the milk.

Why is it, that when I started to read this thread, I was licking my lips?