Is morality "instinctual"? There's reason to believe at least the core of it is.
From O'Neil, K. L. (2018). The Biologicalization of Morality: Morality as Instinct. (Thesis USF)
"Hauser surveyed people across geographic, cultural, and religious barriers. (The trolley dilemmas were even translated to situations involving crocodiles and canoes so that an indigenous Central African tribe could be surveyed) (Dawkins, 2006a). For each variation of the dilemma, across these barriers, the people surveyed almost universally made the same judgements (Hauser, 2006). Even if their reasons differed or if they were unable to articulate their reasons, the vast majority of people still came to the same conclusions (Hauser, 2006).Thus, it seems that regardless of where you live, what you do, whether you practice a religion, whether you are educated, whether you have access to modern technology, whether you are a hunter-gatherer or a US citizen, etc., you have the same sense of morality as everyone else."
The fact that virtually no one has to stop to "reason" that murder is wrong or that lying is wrong is probably a solid indicator (at least in my humble opinion) that the instincts are already there.
O'Neill further states this in summary:
"Moral behavior is an outcome of natural selection, and ultimately selfish in that it serves to promote the continued existence of the genes that give rise to it. Moral behavior exists because it is adaptive, with moral individuals earning benefits such as reciprocity, reputation, and status. These benefits are just as present for humans in modern society as they were for our hunter-gatherer ancestors. Many species have evolved social systems that incorporate the enforcement of moral rules, resulting in benefits for “good” deeds and punishments for “bad” deeds. These systems help make it possible for selfish organisms to coexist in cooperative societies. Studies have shown that human generosity, trust, and empathy are influenced by chemical substances in the body..."
"Morality is neither a social construct nor anO’Neil 41endeavor of rationality, but primarily an instinct. As creatures who are both highly intelligent andhighly social, humans are predisposed to believe in a higher moral realm, further complicatingour ability to biologicalize the topic. But despite our complex cognitive delusions, we are nodifferent from other animals in that we are wired to strive for the immortality of our genes. Weare not moral because we’re good; we are moral because we’re selfish."