Proteans (or the Proteus effect) are unpredictable, subtle, often subconscious, flirting signals, such as a woman's touching of her hair when first meeting a man.
The term was coined by Humphries and Driver in 1970[1] for unpredictable behaviour exhibited by prey animals.
[2] The researchers named the ritual for the shape-shifting Greek god because of the ambiguity of the signals.
Because of the unconscious nature of proteans, they are not overt invitations to proceed, but more akin to "tells" in a poker game.
This can be clumsy and confusing to both parties, and understanding the concept of protean signals is useful for avoiding such missteps.