Over the past few centuries a shift has been seen, from the likes of strict adherence to Christianity (at least, in Europe) to greater reliance on science, etc. as observed by Friedrich Nietzsche. With this, however, Nietzsche predicted that a great helplessness and feeling of desperation would emerge in the masses because of a lack of defined purpose/meaning (exemplified in the quote, "God is dead. God remains dead. And we have killed him. How shall we comfort ourselves, the murderers or all murderers?"). While the likes of science can give us detailed descriptions of how things are, they do not have anything to say on how one ought to act, for example, the statement that:
childhood corporal punishment, such as spanking and beating, has negative psychological effects in the development of children and contributes to adult anxiety and depression
...does not necessarily mean that for someone who "relies on science" childhood corporal punishment is bad - it merely states that childhood corporal punishment has negative side effects later in life.
Most people seem to intuitively remedy this problem by living by (or at least trying to live by) the precepts:
the "Golden Rule"
doing the greatest good to the most number of people
These precepts are ubiquitous in both Western and Eastern philosophy, and to most people come as common sense and basic reason (not to disparage the philosophers who first wrote about it). The aforementioned precepts lend themselves to utilitarianism, a family of ethical theories only really developed in the 1700s and 1800s.
My question is, is there a reason that this way of thinking, in the absence of religious dogma, is so widespread? Is there a reason that other moral systems aren't more intuitive to us (of course, this could just be because the basic ideas behind utilitarianism are so straightforward and easy to grasp) and that "the Golden Rule" became ubiquitous? Perhaps a writer or philosopher that was highly influential in his/her time? If not that, what does the intuitiveness of "the Golden Rule" and utilitarianism say about how humans, on a biological/sociological level, perceive social systems and the ways in which to interact with and treat the people around them?