Agesture that conveys conventional meanings that are recognized by members of a given culture, such as a hand wave or a nod of the head, is called a/an

These gestures are known as emblems. An emblem is a gesture that conveys a specific non-verbal meaning that is understood by members of a particular culture or sub-culture. Unlike general shows of kindness such as smiling, emblems have specific meanings within specific contexts. Thumbs up for example may mean something specific in the United States, but will mean something completely different in Germany or other parts of the world.

If the experiment was perfomed more then once and you get the same results