Mediated semantic priming interference in toddlers as seen through pupil dynamics

Prime saliency in semantic priming with 18-month-olds

This study investigated semantic priming in 18-month-old infants using the inter-modal priming technique, focusing on the effects of prime repetition on saliency. Our findings showed that prime repetition led to longer looking times at target referents for related primes compared to unrelated primes, supporting the existence of a structured semantic system in infants as young as 18 months. The results are consistent with both Spreading Activation and Distributed models of semantic priming. Additionally, our findings highlighted the impact of prime-target stimulus onset asynchronies (SOAs) on priming effects, revealing positive, negative, or no priming effects depending on the chosen SOA. A post-hoc explanation of this finding points to negative priming as a possible mechanism. The study also demonstrated the utility of the inter-modal priming task in studying lexical-semantic structure in younger infants with its diverse measures of infant behaviour.

Applicability and usefulness of pupillometry in the study of lexical access. A scoping review of primary research

Pupil dilation has been associated with the effort required to perform various cognitive tasks. At the lexical level, some studies suggest that this neurophysiological measure would provide objective, real-time information during word processing and lexical access. However, due to the scarcity and incipient advancement of this line of research, its applicability, use, and sensitivity are not entirely clear. This scoping review aims to determine the applicability and usefulness of pupillometry in the study of lexical access by providing an up-to-date overview of research in this area. Following the PRISMA protocol, 16 articles were included in this review. The results show that pupillometry is a highly applicable, useful, and sensitive method for assessing lexical skills of word recognition, word retrieval, and semantic activation. Moreover, it easily fits into traditional research paradigms and methods in the field. Because it is a non-invasive, objective, and automated procedure, it can be applied to any population or age group. However, the emerging development of this specific area of research and the methodological diversity observed in the included studies do not yet allow for definitive conclusions in this area, which in turn does not allow for meta-analyses or fully conclusive statements about what the pupil response actually reflects when processing words. Standardized pupillary recording and analysis methods need to be defined to generate more accurate, replicable research designs with more reliable results to strengthen this line of research.

Word prediction using closely and moderately related verbs in Down syndrome

People with Down syndrome (DS) have several difficulties in language learning, and one of the areas most affected is language production. Theoretical frameworks argue that prediction depends on the production system. Yet, people with DS can predict upcoming nouns using semantically related verbs. Possibly, prediction skills in people with DS are driven by their associative mechanism rather than by the prediction mechanism based on the production system. This study explores prediction mechanisms in people with DS and their relationship with production skills. Three groups were evaluated in a preferential-looking task: young adults, children with DS, and a typically developing control group paired by sex and mental age. Participants saw two images, a target and a distractor. They also heard a sentence in one of the three conditions: with a verb that was closely related to the object (e.g., "The woman read the book"), with a verb that was moderately related to the object (e.g., "My uncle waited for the bus"), or with a verb that was unrelated to the object (e.g., "My sister threw a broom"). Their productive vocabulary was then measured. In the young adult and typically developing groups, the results showed prediction in sentences with highly and moderately related verbs. Participants with DS, however, showed prediction skills only in the highly related context. There was no influence of chronological age, mental age, or production on prediction skills. These results indicate that people with DS base prediction mainly on associative mechanisms and they have difficulty in generating top-down predictions.