Investigating Two Domain-General Processes in Early Infancy: Disjunctive Inference and Reorientation of Attention

A characteristic of the more evolved nervous systems is the ability to process information in an abstract amodal domain. The existence of this capability, necessitates the presence of mental processes that are amodal and therefore, can act on a broad range of internal and external stimuli. Investigating the early development of the interaction between the amodal mental processes and their domain of action on mental representations, can shed light on the extents of the computations that can be accommodated by these processes. In this thesis through a series of eye-tracking studies in pre-verbal infants, we attempted to investigate the early development of some of these interactions from two different domains. In one domain, we addressed if logical operators, as a subset of the mental processes, are available to pre-verbal infants; so they can be utilized in combining and assessing the several mental images involved in an inference process. For this purpose, we introduced a face-voice association paradigm, in which infants could potentially use disjunctive inference to disambiguate the context and make the right face-voice pairings. We showed that the performance of the 10-month-old infants suggests that they might be able to perform this association through the process of disjunctive inference based on the elimination of the incorrect alternative. We furthermore, used the pupillometry data and results from an adult control group to suggest a time-frame for the steps of this process. In another domain, we studied the integration of abstract visual icons with attentional shift. In one hand we showed that arrows can trigger an attentional shift in the 4-month-old infants but not 8-month-olds. We further showed that this reorientation of attention might be due to the triangular area of the icon. These striking results, although should await further confirmations, suggest an early sensitivity to the features of these icons, which can trigger a top-down reorientation of attention (as we tried to eliminate the possibility of a bottom-up process). A sensitivity that possibly disappears later in the development. On the other hand, we showed that 8-month-olds and not 4-month-olds can assign an attentional shift to an arbitrary icon in a very few number of trials. These results together suggest a mixed picture for attribution of attentional shift to the icons; however indicating that a volitional attribution of attention to arbitrary icons can be carried out by infants as young as 8 months of age.