Why do many people find lighter women more attractive?

I would have picked the light-skinned one, but you have to admit the lighter skinned one does look prettier if have been brainwashed with media like me and a biased fashion sense, but you probably did the experiment with white people as a majority, so they would probably want to pick something that looks the closest to themselves in a way, not to be offensive but you don't see many people that dark, that often for example in your life (in my case, I live in central London), or celebrities. Most of the time people try to lighten their skin if they are dark skinned, you see this all the time the editing process of magazines. It is basically racism, but people don't really know they are doing this, it is stereotyped that the darker your skin the poorer you are.