The explanation of human nature exclusively from the perspective of biological evolution (as for example in sociobiology) faces two paradoxes. The core of the first one can be summarized as follows: The characteristics of the specifically human behavior, such as symbolic thinking, intentional and planned activity, cooperative work distribution, creation of cultural artifacts and social institutions, needed an incommensurable shorter time to develop when compared with the changes effected by the selection of random mutations. The second paradox says: Although the cultural accumulation of Homo sapiens sapiens grew exponentially during the last 10 000 years, the capacity of human brain remained unchanged. What were the mental pre-adaptations, which made these rapid changes possible? The paper discusses the psychological researches, which aim at contributing to the explanation of these paradoxes.