They didn't say subtle, or that you had to track the entirety of the hypothetical 1000.
Now why these social cues are so often subtle or ambiguous is itself an interesting question. It's not one I have any good answers to though. In this area, as in most, I'm a phenomenologist and not a theorist. Needless to say the phenomenology I've developed precludes telling a woman I'm interested in about the phenomenology I've developed. Except of course when I think she might find it attractive. Human social interactions are marvelously complex. Frankly my inclination to start navel gazing has set me back once or twice.