Science confirms what we've known for a long time - humans are unique in their ability to act according to morality, instead of pure survival value. We have eaten from the tree of knowledge of good and evil and have free will. Animals don't.
Our unique talents also include abstract reasoning and communication as well as advanced tool making, yet most human beings are still acting within the mammalian level of behavior which mostly comprises pack warfare and alpha-dominance seeking, and we are all witness to the disastrous effects those sub-human tendencies are having upon each other as well as the Earth itself (via our short-term profit-seeking over the long-term well-being of the Earth for our descendants benefit).
Love -- via selfless service to others' happiness -- is the most unique of human traits as it facilitates our rising above our mammalian tendencies (literally, from a brain structure standpoint) to segregate and wage war upon others of any perceived difference, be it physical (ethnic) or ideological (form of religion, neighborhood, country, sexual orientation or identity, etc.).
Only by accepting the primacy of our free wills upon this Earth and the necessity of our training our minds to differentiate good from evil and then choosing the former can we stop the devastation of the Earth and its less fortunate individuals.
Until then, the vast majority of human beings will remain, as Wisdom states, "like the animals, only worse".
It can't be modeled scientifically. People deny it because it's in effect a dogma. I don't say that as a slight, our society is built on the notion of free will.
It's simply that the notions exist in a level of abstraction, so the point is moot if you continue living your day to day life, except insofar as you let it affect your mental state.