Photographer preference or image purpose? An investigation of posing bias in mammalian and non-mammalian species.

Portraits of human adults typically exhibit leftward biases--that is, they depict individuals with their left cheek prominently featured. The purpose of this study was to determine if photographs of human infants and photographs of non-human animals also display these leftward biases. We observed significant leftward biases in photographs of infants and non-human animals. The only exception to this was a rightward bias observed for photographs of non-mammalian species that were found on personal websites. As the species sampled were likely unaware of the purpose of the photographs, our data are consistent with the interpretation that these biases reflect the preference of the photographer.