The results of a research of the obverse asymmetry influence on the perception of a number of personal characteristics of man including rationality and irrationality in cognition are described in the article. It has been shown that in perception of vertically divided (along the nose line) face pictures the psychological characteristics perceived by each half of the face is partially different. However, the rationality or irrationality in cognition is perceived by any half of the face — right or left — equally well.