The Apple Watch may already have become the most popular sophisticated wearable device, but like any other such device it has some strange side-effects.

For those who enjoy people-watching – and there are few more fascinating hobbies when you are in an urban area – here are some new quirks to watch out for.

The hand looking for a tip, or Erb’s non-palsy

Someone walks round with their hand held palm out and slightly upturned, as if a waiter expecting you to place a gratuity in that hand.

Interpretation: I have got a new Apple Watch, and am still learning how to prevent it from activating inadvertently.

Note: Occasionally this is a classical sign of Erb’s palsy, a medical condition resulting from damage to a plexus of nerves under the armpit. If it persists, advise the person to seek medical attention. However Erb’s palsy is much less prevalent than the Apple Watch.

The forearm repeatedly engaged in florid gesturing

Someone keeps rotating and moving one forearm, looking downward at it whilst doing so, eventually clutching it with the other hand.

Interpretation: I have got a new Apple Watch, and am still learning how to activate it so that I can tell the time from it.

Note: Similar gestures may also occur when speaking certain languages, particularly with passion. In those cases, the eyes are usually fixed on the other person who is supposed to be listening, and the terminal clutch is absent.

Others

Early reports are that those with Apple Watches engage in many other behaviours, such as talking into a hand and wrist, repeatedly tapping one wrist, and more. They are surely people to watch.