The paper report results from a psychological study of 90 biology students (Moscow State University) and five doctors of biology. Faculty expert opinions were used to determine ten most successful performers and ten poor performers among students. They were compared by several cognitive and personal factors. The paper shows that success in scientific work is connected not with separate cognitive, communicative and personal characteristics, but with their system interaction. When this interaction is not stable and optimal, efficiency of scientific work is low even if the level of personal development and cognitive abilities are relatively high.