We consider the evolutionary scheme of morality proposed by Tomasello to defend the idea that the ability to orient the learning of offspring using signs of approval/disapproval could be a decisive and necessary step in the evolution of human morality. Those basic forms of intentional evaluative feedback, something we have called assessor teaching, allow parents to transmit their accumulated experience to their children, both about the behaviors that should be learned as well as how they should be copied. The rationale (...) underlying this process is as follows: if a behavior is approved, then it is good; if it is disapproved, then it is bad. The evaluative guidance on how to behave most probably spread among peers in situations of mutual benefit, such as cooperative child rearing. We argue that our hominin ancestors provided with this capacity for assessor teaching were ideally positioned to develop the two specifically human levels of morality proposed by Tomasello: the morality of fairness and the morality of justice. Assessor teaching could have facilitated the genesis of rudimentary codes of behavior tied with the need to agree about how to behave to succeed in joint cooperative activities. Moreover, learning through assessor teaching provides a plausible explanation for the origin of the objectivist and prescriptive dimensions of human morality. First, we emphasize that individuals feel that they evaluate the behavior of others objectively to guide their learning, and, second, we underline the imperative intention that any moral manifestation possesses. (shrink)