Why is the left half of the face more beautiful than the right?

To find out whether the perception of the left and right side of the face is really different, the researchers asked volunteers to rate the attractiveness of faces from photographs. The interest in the image was assessed not only by the results of the survey, but also by the degree of pupil dilation. As you know, the pupils dilate when we are interested in something, and narrow when we see something unpleasant. As a result, it turned out that images of the left side of the face are indeed considered more emotional and aesthetically pleasing.

This phenomenon can be explained by the fact that the left side of the face is controlled by the right hemisphere of the brain, which is responsible for figurative thinking. 

There is a second version, which says that this is due to the peculiarities of intrauterine development of the fetus.