Figure 1.

Representative images of twins in their original photographs (top images) and in their swapped images (bottom images). To analyze face controlling for surrounding, perceived ages from vertically opposite images were compared, whereas to analyze the surrounding controlling for face perceived ages from diagonal opposite images were compared. Lighting in the female images and the angle of presentation of the face to the camera in the male images were the two main varying technical parameters between the images; both male faces (upper images) were flipped horizontal (lower images) to compensate for the varying angle. All twins gave written consent for their images to be published.