Motion parallax allows 7-8-month-old infants to distinguish pictures from their referents

Earlier research has shown that seven-month-old infants prefer to look at real objects over their referents. Which visual cues determine that preference? Motivated by research on adult observers highlighting the significance of motion parallax over other depth cues contributing to a sense of presence and place, we tested the hypothesis that motion parallax alone is sufficient to cause preferential looking to real objects in infants. We presented pairs of displays of toys in different formats: (a) The real three-dimensional toy; (b) a realistic image of that toy presented on screen; (c) the same image, but with added depth-from-motion-parallax. Infants preferred (a) over (b) (57% vs. 43%, p < .01) and (c) over (b) (52% vs. 48%, p < .05), but showed no significant preference between (a) and (c) (51% vs. 49%, n.s.). This supports the hypothesis that motion parallax alone can induce a looking preference comparable to that observed for real objects.