Evaluating the Rule of Thirds in Photographs and Paintings

The rule of thirds (ROT) is one of the best-known composition rules used in painting and photography. According to this rule, the focus point of an image should be placed along one of the third lines or on one of the four intersections of the third lines, to give aesthetically pleasing results. Recently, calculated saliency maps have been used in an attempt to predict whether or not images obey the rule of thirds. In the present study, we challenged this computer-based approach by comparing calculated ROT values with behavioral (subjective) ROT scores obtained from 30 participants in a psychological experiment. For photographs that did not follow the rule of thirds, subjective ROT scores matched calculated ROT values reasonably well. For photographs that followed the rule of thirds, we found a moderate correlation between subjective scores and calculated values. However, aesthetic rating scores correlated only weakly with subjective ROT scores and not at all with calculated ROT values. Moreover, for photographs that were rated as highly aesthetic and for a large set of paintings, calculated ROT values were about as low as in photographs that did not follow the rule of thirds. In conclusion, the computer-based ROT metrics can predict the behavioral data, but not completely. Despite its proclaimed importance in artistic composition, the rule of thirds seems to play only a minor, if any, role in large sets of high-quality photographs and paintings.