Picture book reading is a very common form of interaction between parents and very young children. Here we explore to what extent young children transfer novel information between picture books and the real world. We report that 15- and 18-month-olds can extend newly learned labels both from pictures to objects and from objects to pictures. However, the degree to which they do so is affected by iconicity--how much the objects and pictures resemble one another. The children in these studies more often extended the labels between picture and object when realistic photographs and drawings were involved than less realistic cartoons. These results show that higher levels of perceptual similarity between symbol and referent make the referential relation more transparent, thereby helping children transfer information between them. Thus, the educational function of early picture book interactions may best be served with realistic illustrations. (Contains 2 footnotes and 3 figures.)