There are better ways to question the ethics of the experiment. Here's a simple approach:
Would anyone want their emotions manipulated to be unhappy or unhealthy?
The corollary in a medical experiment would be, would a healthy person want to undergo an experiment that could make them sick?
Some people mentioned advertising as a counterpoint, that what Facebook does is not at all different from advertising's psychological manipulation. Well maybe some forms of advertising ought to be regulated too. Would a child voluntarily want their emotions manipulated by a Doritos ad to make the sicker or fatter?
Even if it's not known what the outcome is, the two points are:
(1) Facebook's various policies specify you will randomly participate in their studies, but
(2) It matters if an experimental outcome can harm you.
So even though you agreed to participate in experiments, you weren't told the experiments could hurt you. That is a classic medical ethics violation, and it ought to be a universal scientific ethics violation.
"Well maybe some forms of advertising ought to be regulated too."
In the UK, advertising using subliminal messages/stimuli is not permitted: "No advertisement may use images of very brief duration, or any other technique that is likely to influence consumers, without their being fully aware of what has been done."[0]
every time someone asks me 'how are you doing' and doesn't mean it, it makes me a little less happy inside. i have to work hard to focus my thoughts on their intent - to greet me - and not on the fact that they asked a question i'd love to answer but they don't want to hear the answer to, because they don't mean what they are saying.
it hurts.
but nobody's going to say it's "unethical" to ask people how they're doing unless you mean it.
so if someone gauges people's reactions, and realizes 'hey, people don't like this' - they've already commited an "ethical violation" according to research ethics defined this way.
people don't like emotional manipulation. i get that - but laws don' fix the problem. laws ignore emotion; they make no special cases. if anything, our society's obsession with rules that are specifically designed to _prevent_ emotion from changing our decision making just makes this worse.
Would anyone want their emotions manipulated to be unhappy or unhealthy?
The corollary in a medical experiment would be, would a healthy person want to undergo an experiment that could make them sick?
Some people mentioned advertising as a counterpoint, that what Facebook does is not at all different from advertising's psychological manipulation. Well maybe some forms of advertising ought to be regulated too. Would a child voluntarily want their emotions manipulated by a Doritos ad to make the sicker or fatter?
Even if it's not known what the outcome is, the two points are:
(1) Facebook's various policies specify you will randomly participate in their studies, but
(2) It matters if an experimental outcome can harm you.
So even though you agreed to participate in experiments, you weren't told the experiments could hurt you. That is a classic medical ethics violation, and it ought to be a universal scientific ethics violation.