[This Physorg article reports research published in the March issue of Psychological Science, a journal of the Association for Psychological Science, is suggesting that we process images in two very distinct ways. From the article: " Ben-Gurion University of the Negev Psychologist Tzvi Ganel and his colleagues presented research participants with the “Ponzo” illusion, an image common in psychological research that makes two objects that are similar in length appear drastically different. They then hooked participants’ index finger and thumb to computerized position tracking equipment and asked them to grasp the objects with their fingers.
Even thought the object appeared to be larger (or smaller) than it really was, the size of their grasp reflected the object’s real rather than apparent size. For good measure, the researchers arranged the illusion so that the object that appeared to be the smaller of the two was actually the larger of the two.