By demonstrating that a single label does not refer to a unique referent (i.e., a specific target picture), the multiple example conditions may have increased children’s awareness that words can be extended to various items in one’s environment, including perceptually similar objects. By contrast, the process of repeatedly pairing a verbal label with one target picture in single exemplar trials may have narrowed the relation to the extent that the picture itself (rather than the depicted object) was more frequently considered the referent of the word (Plaisted, 2001; Preissler, 2008; Hartley and Allen, 2015a). Thus, the nature of the pictures being presented may be a more important influence on symbolic learning in ASD than whether they are presented on an iPad or in a book.