Any A/B test is "experimentation on humans". Facebook and all other web giants constantly do such behavioral studies. The only difference is that this one was p

Any A/B test is "experimentation on humans". Facebook and all other web giants constantly do such behavioral studies. The only difference is that this one was published. In other words, if someone argues that this was unethical experimentation on humans, then there are 1,000 other studies we never heard of that are far, far worse. But we know they exist. It doesn't make sense to argue that. Websites have to experiment with different ways of doing things, and seeing how that affects their users. This isn't just a web thing either, of course - businesses need to try different things in order to optimize themselves. And to measure which is the best to get people to spend more.