I´ll get WAY out there into spiritual territory to answer you. I believe in reincarnation because I´ve had some experiences that confirmed to me that it exists, so I believe that it´s not only the human species that physically evolves in its DNA, but also the souls that get to inhabit the new bodies. You can´t force a more evolved mindset artificially because it would be like a child pretending to be an adult. It would feel totally unnatural and even make you miserable. Right now, at this stage of my life I´m at Psychological Egoism as well, so that´s what I embrace. (Btw, I already tried to be totally selfless but it made me miserable, it´s not who I am yet, so I´m speaking with personal experience on that).