Duplicate of https://news.ycombinator.com/item?id=19991696 (two days ago).

Keep in mind that the paper does clearly state:

>Furthermore, all three forms of social class were positively associated with actual rank, indicating that those with relatively high social class did objectively better on the flashcard game relative to their lower-class counterparts

This is a poor title and article if you take even a brief moment to view the actual correlations presented in the paper.