How does the user learn about various Gesture on the interfaces ?

1. Does the ipad or android device teach or have inbuilt various gestural interfaces when someone buys a new device? 
2. Does it demonstrate the gestures involved when somebody buys or downloads an app?
3. Does the app provides an intro of various Gestures it takes care of?

Am asking this because it looks that user goes into a stream of trial and error to understand an app or use the app, by trying various ways to move across the screens - sometimes succeed, fail or get frustrated.

Any research, evidence or observations?