Kenneth B Clark - Skin Color as a Factor in Racial Identification - Psychology audiobook 

The study goes like this: Imagine a bunch of children are examined....every year; at 3, 4, 5 years old ect. ......and in each session they are sat down one by one, at each of these ages and shown 1 of 3 pictures each time (a light, medium, and dark skinned child in random scenarios) and asked who is the prefered child of the three pictures they are shown. The theory states a child's choice of preference is a reflection of wishful thinking (and that wishful thinking is based on racial classism in America). A white child in America would rightfully chose the white boy, and (based on the theory) a black/medium child "should" also chose the white boy or if they dont, be subject to the wishful thinking hypothesis. The study results show...that, yes the white child chooses the white boy more, and the black child chooses the white boy more...the medium child's choices, however, are where the interesting bit of this study shines.

He's talking about how people choose each other based on how we look.