http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3108582/
http://journals.plos.org/plosone/article?id=10.1371/journal....
And most emotionally driven ethical discussions on HN lean towards popularity contests - compare the outcry against online harassment of that gamergate girl to the online harassment of Charles Carreon (https://en.wikipedia.org/wiki/Charles_Carreon), for example.
But even if you are right, what does diversity in the traditional sense of your post above have to do with it? Are you suggesting that women/LGBTQ+ people are more emotional and less rational?
Geez, I really hope that that was just an unfortunate turn of phrase. You can't possibly mean that non-(white-males) have a quote "more emotionally-driven perspective", do you?
There is a big difference and yes, "manipulating the user" is sinister.
That's not a lie or bending the truth. It is manipulating the user.
It sounds like you are decorating the showroom to boost sales... I hope it works out well for you. I was thown by the initial desciption that sure didnt sound like faces and buttons: "I'm streaming realtime events and then running statistical models on the datastream in order to manipulate user behavior."
Having a more diverse team that includes someone with a more emotionally-driven perspective could lead to someone asking the question "Is the way we're manipulating user behavior actually ethical?"
This isn't about finding different technical solutions to problems; it's about finding different problems.