[PeterisP]

An more accurate description of the function would be "given this picture of a screen, what is the most likely key my author was pressing in this situation" - no goals, no values, no optimization, but simply learning to imitate the actions performed by a human.

Coincidentally, one of the neural network components in AlphaGo did pretty much the same, i.e. attempted to guess what human player would usually play in this situation purely based on the image and nothing else.