You are cordially invited to the Defense of PhD thesis
titled
Nonverbal Generics:
Ostensive Communication Aids Kind-Based
Representation of Objects and Acquisition of Generic Knowledge in Infancy
by
Rubeena Shamsudheen
Primary supervisor: Gergely Csibra
Secondary supervisor: György Gergely
Thesis submitted to:
Central European University
Department of Cognitive Science
Abstract
Humans can acquire generic knowledge from each other directly, via linguistic communication. This thesis reports studies that demonstrate that nonverbal ostensive
communication can induce kind-based representation of objects in preverbal infants. Such representations license information conveyed about the objects to be bound to their kinds thus aiding one-shot acquisition of generic knowledge. Chapter 1 summarizes previous work
on infants’ representation of objects and sensitivity of ostensive communicative signals and raises our hypotheses on how the latter modulates the former. The study reported in Chapter 2 investigated whether nonverbal ostensive reference, mediated via deictic gestures, is
sufficient to establish kind-based representations of familiar objects. We found that 9-monthold
infants, who do not spontaneously form kind-based representations of objects, are successful at an individuation task with distinct objects of familiar kinds when the objects are ostensively referred. However, they fail if the objects are from the same kind but differ on
kind-irrelevant features, such as color. These findings confirmed the hypothesis that ostensive
referential communication can induce kind-based representation of exemplars of object kinds
that are known to infants. Chapter 3 reports a set of experiments that explored whether ostensive demonstration of a dispositional property of an object is encoded as generic property. Eighteen-month-olds were tested on their inclination to extend the demonstrated
property to other exemplars of the same kind even after encountering a counterexample – another object without the property. We found that the infants who received ostensive demonstration displayed resistance to counterevidence, a signature of having acquired generic
knowledge about the given kind of objects. In contrast, the infants who had received nonostensive
demonstration reacted the counterevidence as if they extended the property to other exemplars via inductive generalization. This study also explored the role labels play in generic knowledge acquisition and inductive generalization. Chapter 4 investigated whether ostensive
reference plays a role in how linguistic labels are promptly linked to object kinds instead of to the specific object that is labeled. The results suggest that ostensive reference prompts infants to represent novel objects by opening a kind placeholder to which predicates, such as labels,
can be bound. These findings shed light on the existence of a phenomenon t hat we have dubbed ‘nonverbal generics’: human infants are predisposed to interpret nonverbal ostensive communication akin to how sophisticated language users interpret verbal generic statements.
Such interpretational mechanisms allow young infants to rely on knowledgeable others, who engage them in pedagogical interactions, to accumulate knowledge about culturally shared concepts, such as generic properties of object kinds.