This is related to the phenonomen coined "mogging" by the pick up artist industry.

Basically, the premise is that your attraction to a specific man lowers if there is a more attractive man in near proximity - like you are watching the mechanism of hypergamy in real time.

It's subtle but important - if you are a guy talking to a girl or a girl notices you and she does find you attractive, however, another more attractive men is close by, it can automatically shift her "Attraction threshold" so that you do not meet it - and it shifts towards the "hotter" man. Again - the subtle yet important key thing is that it SHIFTS the threshold so you are NO LONGER IN IT and therefore no longer a viable option. Obviously, if you talk to the women and the other guy doesn't you can change things.

Example A: Tim is an above average guy. he is at an enviroinment event mostly women and few men. He catches Lisa's eye. she immediately finds him cute. they start chatting.

Example B: Tim is an above average guy. he is an an environment with most men and a few women. A lot of the men are classically attractive/charismatic. Lisa first notices Tim, and finds him attractive, but then notices Tyrone and Tanner - two far more attractive/charming men close to time. they both dwarf Tim with their height and confident body language. She suddenly loses attraction towards Tim and does not know why.

this has huge implications for selecting the right environment for men - as the first impression is the great filter. Men should avoid trying to flirt with women in environments where there are are more attractive/successful men. Good examples are gyms (there is also a man that is more ripped/taller/athletic), business conventions (also a man who is more charismatic/in a better suit/etc), and even night outs (lots of competition).

Focus more on envrionments where you are more likely to be the most/more attractive guy (more women, less men basically).