Eyes not only draw attention but also guide attention.
People notice people. For lots of reasons, we are built to do that. As such, the presence (or not) of people in images can change how we look at, move through, interact with, and interpret a painting, a magazine, or even content on an individual page.
Very interesting finding from Human Factors, who conducted eye tracking study on Sunsilk’s display ad. The eye tracking results are also conveyed in in heatmap overlaid on the original image. The red hotspots define where people looked most often:
When the woman looks at you, you tend to look at the woman and the tagline. The product is ignored. When the woman looks at the product, you tend to look at the woman, the tag line and the product.
Lesson: for image ads to be effective online, an image needs to draw people and drive them to look towards the thing being touted.