According to the dual inheritance theory, cultural learning in our species is a biased and highly efficient process of transmitting cultural traits. Here we define a model of cultural learning where social learning is integrated as a complementary element that facilitates the discovery of a specific behavior by an apprentice, and not as a mechanism that works in opposition to individual learning. In that context, we propose that the emergence of the ability to approve or disapprove of offspring behavior, orienting their learning (a process we call assessor teaching), transformed primate social learning into a cultural transmission system, like that which characterizes our species. Assessor teaching facilitates the replication and/or reconstruction of behaviors that are difficult to imitate and helps to determine which behaviors should be imitated. We also explore the form in which assessor teaching has conditioned the evolution of our abilities to develop cultures in the hominin line, converting us into individuals equipped with what we call a suadens psychology. Our main point is to defend the hypothesis that suadens psychology determines the stability and dynamics that affect the trajectories of many cultural characters. We compare our proposal with other theories about cultural evolution, specifically with dual inheritance theory and cultural attraction theory.