[polarix]

The assertion that this study refuted was that too much positive bias in a filtered source of information causes negative sentiment. Reducing said positive bias had heretofore unknown effects. The attempt was to learn, not to negatively influence anyone's mental state.

[chris_wot]

Just like the Milgram Experiment was designed to see whether a small number of people could be coerced into believing they are torturing and killing people when so ordered? It wasn't designed to cause mental distress, but to see what happened.

You see, that's why there are ethics committees at Universities.