According to Paul Bloom, one of the leading researcher on the moral life of infants, found that infants have some capacity to distinguish between kind and cruel action, have empathy when observing pain of those around them, a sense of fairness when dividing resources and justice, and when seeing good action rewarded and bad action punished.
These are biological rooted moral intuitions and not learned ones.
They are rooted in the Pre frontal Cortex (PFC) and the Amygdala. The PFC is the rational center while the Amygdala is the emotional center of the brain. People who have larger and thicker Amygdales are more conservative and are more sensitive to uncertainty and cognitive dissonance, while others with a larger volume of PFC are more caring and sensitive to fairness. Alcohol reduces the influence of the PFC over the Amygdala.
The research establishes that morality originates in the brain, develops throughout a life time, to make living in a large group possible and is not the result of the commands of an imaginary supernatural force but that “ethical intuitionism is basic moral knowledge that is not inferred from or based on any proposition” (Wikipedia)