Beauty is in the iris: Constricted pupils (enlarged irises) enhance attractiveness

Physical attractiveness profoundly affects a broad array of life experiences and outcomes, and the eyes are an important determinant of physical attractiveness. We investigated whether a particular feature of the eyes - pupil size - affects perceived attractiveness. We present competing theoretical predictions of whether dilated (larger) or constricted (smaller) pupils should appear more physically attractiveness. Youthful features tend to be attractive (i.e., neoteny), and pupil size decreases across the lifespan, so dilated (enlarged) pupils may be more attractive as a signal of youth. Alternatively, constricted (small) pupils may be more attractive because, by revealing more of the iris, they increase both color and brightness of the eyes. The present experiments demonstrate that people appear more attractive when their pupils are constricted (Experiments 1-3). This effect is equally large with black-and-white images, indicating that color per se is not necessary for the effect (Experiment 4). Rather, constricted pupils make eyes appear brighter, which in turn renders the face more attractive (Experiment 5), even when controlling for how colorful the eyes appear (Experiment 6). These results identify constricted pupils as a novel facial feature that enhances attractiveness.