he use of a symbolic gesture to label an object or to make a request seems to "pull" language from caregivers as they acknowledge the infant's message or even elaborate on it: "Birdie? That's right! That is a birdie! Oh, there it goes flying away. Bye-bye birdie!" It follows, then, that the more things an infant can and does talk about, the more vocal language the infant will hear in return. Because symbolic gestures tend to be acquired more easily and at earlier ages than their verbal counterparts (Acredolo & Goodwyn, 1992; Goodwyn & Acredolo, 1993, 1998), infants with symbolic gestures in their communicative repertoires gain the benefits of such caregiver responses at earlier ages as well. In other words, a 14-month-old with a 10 word and 10 symbolic gesture vocabulary can elicit caregiver responses to twice as many different things as he or she could without the additional gestural symbols. In addition, it seems quite likely that caregivers who are purposefully encouraging symbolic gesturing by modeling them will be especially vigilant about acknowledging and reinforcing any attempts their baby makes to use them, thereby rarely missing an opportunity to flood the child with relevant vocal language.Topic selection. A second factor known to contribute to faster rates of verbal language development is the degree to which the infant or toddler, rather than the parent, controls the topic around which joint attention episodes are organized. The classic demonstration of this relationship was provided in a study by Tomasello and Farrar (1986) in which the use of object names by mothers to refer to objects upon which the child was already focused was positively correlated with later vocabulary size. The explanation for this is obvious. Just as we all do, infants tend to pay better attention to things in which they are genuinely interested, as opposed to things in which others think they should be interested. For example, a toddler at the zoo ...
