I can confirm this is true. Last year, as an experiment, I made a dummy account with a picture of former NFL quarterback Kyle Boller but the same profile/personality as me. His matches are significantly more attractive than mine. He also received this email a few weeks after registration:
We just detected that you're now among the most attractive people on OkCupid.
We learned this from clicks to your profile and reactions to you in Quickmatch and Quiver. Did you get a new haircut or something?
Well, it's working!
To celebrate, we've adjusted your OkCupid experience:
You'll see more attractive people in your match results.
This won't affect your match percentages, which are still based purely on your answers and desired match's answers. But we'll recommend more attractive people to you. You'll also appear more often to other attractive people.
Sign in to see your newly-shuffled matches. Have fun, and don't let this go to your head