The present paper tried to review the recent trend of the studies on the nature/nurture problem. (1) Several researches in the last decade have revealed that the genetic factor has a strong influence on the individual differences of IQ, even if the shortcomings of the traditional twin and adoption studies are revised. (2) Intelligence in the sense of Piagetian scheme, however, changes developmentally, and its developmental prosess is influenced successively by gene throughout one's life. (3) The belief that to be genetic implies to be stable should be discarded, if we distinguish between the perspective of individual differences and the persprective of species. In addition, confusion and misunderstanding in the usage of the terms "interaction" and "heritability" must be avoided. (4) Several aspects of correlation underlying the interaction pattern at the phenotypic level were reconsidered. (5) As an attempt to overcome the shortcomings of past studies which treated the character in terms of one dimension, an experimental study using multidimensional scaling was proposed.