I think that experiment wouldn’t prove anything about the algorithm’s “intentions,” which seem to be the interesting part of the claim. One experiment that maybe would (I have no idea if this is practical) is giving the algorithm the chance to recommend two pieces of content: a) high likelihood of being clicked on, b) lower likelihood of being clicked on, but makes the people who do click on it more polarized. Not sure if a natural example of such a piece of content exists.
I think that experiment wouldn’t prove anything about the algorithm’s “intentions,” which seem to be the interesting part of the claim. One experiment that maybe would (I have no idea if this is practical) is giving the algorithm the chance to recommend two pieces of content: a) high likelihood of being clicked on, b) lower likelihood of being clicked on, but makes the people who do click on it more polarized. Not sure if a natural example of such a piece of content exists.