Eye-movement patterns to social and non-social cues in early deaf adults.

Previous research on covert orienting to the periphery suggested that early profound deaf adults were less susceptible to uninformative gaze-cues, though were equally or more affected by non-social arrow-cues. The aim of this work was to investigate whether spontaneous eye movement behaviour helps explain the reduced impact of the social cue in deaf adults. We tracked the gaze of 25 early profound deaf and 25 age-matched hearing observers performing a peripheral discrimination task with uninformative central cues (gaze vs arrow), stimulus-onset asynchrony (250 vs 750 ms), and cue validity (valid vs invalid) as within-subject factors. In both groups, the cue effect on reaction time (RT) was comparable for the two cues, although deaf observers responded significantly slower than hearing controls. While deaf and hearing observers' eye movement pattern looked similar when the cue was presented in isolation, deaf participants made significantly more eye movements than hearing controls once the discrimination target appeared. Notably, further analysis of eye movements in the deaf group revealed that independent of the cue type, cue validity affected saccade landing position, while latency was not modulated by these factors. Saccade landing position was also strongly related to the magnitude of the validity effect on RT, such that the greater the difference in saccade landing position between invalid and valid trials, the greater the difference in manual RT between invalid and valid trials. This work suggests that the contribution of overt selection in central cueing of attention is more prominent in deaf adults and helps determine the manual performance, irrespective of the cue type.

Signed Languages: A Triangular Semiotic Dimension.

Since the beginning of signed language research, the linguistic units have been divided into conventional, standard and fixed signs, all of which were considered as the core of the language, and iconic and productive signs, put at the edge of language. In the present paper, we will review different models proposed by signed language researchers over the years to describe the signed lexicon, showing how to overcome the hierarchical division between standard and productive lexicon. Drawing from the semiotic insights of Peirce we proposed to look at signs as a triadic construction built on symbolic, iconic, and indexical features. In our model, the different iconic, symbolic, and indexical features of signs are seen as the three sides of the same triangle, detectable in the single linguistic sign (Capirci, 2018; Puupponen, 2019). The key aspect is that the dominance of the feature will determine the different use of the linguistic unit, as we will show with examples from different discourse types (narratives, conference talks, poems, a theater monolog).

Cognitive, cultural, and linguistic sources of a handshape distinction expressing agentivity.

In this paper the cognitive, cultural, and linguistic bases for a pattern of conventionalization of two types of iconic handshapes are described. Work on sign languages has shown that handling handshapes (H-HSs: those that represent how objects are handled or manipulated) and object handshapes (O-HSs: those that represent the class, size, or shape of objects) express an agentive/non-agentive semantic distinction in many sign languages. H-HSs are used in agentive event descriptions and O-HSs are used in non-agentive event descriptions. In this work, American Sign Language (ASL) and Italian Sign Language (LIS) productions are compared (adults and children) as well as the corresponding groups of gesturers in each country using "silent gesture." While the gesture groups, in general, did not employ an H-HS/O-HS distinction, all participants (signers and gesturers) used iconic handshapes (H-HSs and O-HSs together) more often in agentive than in no-agent event descriptions; moreover, none of the subjects produced an opposite pattern than the expected one (i.e., H-HSs associated with no-agent descriptions and O-HSs associated with agentive ones). These effects are argued to be grounded in cognition. In addition, some individual gesturers were observed to produce the H-HS/O-HS opposition for agentive and non-agentive event descriptions-that is, more Italian than American adult gesturers. This effect is argued to be grounded in culture. Finally, the agentive/non-agentive handshape opposition is confirmed for signers of ASL and LIS, but previously unreported cross-linguistic differences were also found across both adult and child sign groups. It is, therefore, concluded that cognitive, cultural, and linguistic factors contribute to the conventionalization of this distinction of handshape type.

Sign vocabulary in deaf toddlers exposed to sign language since birth.

Lexical comprehension and production is directly evaluated for the first time in deaf signing children below the age of 3 years. A Picture Naming Task was administered to 8 deaf signing toddlers (aged 2-3 years) who were exposed to Sign Language since birth. Results were compared with data of hearing speaking controls. In both deaf and hearing children, comprehension was significantly higher than production. The deaf group provided a significantly lower number of correct responses in production than did the hearing controls, whereas in comprehension, the 2 groups did not differ. Difficulty and ease of items in comprehension and production was similar for signing deaf children and hearing speaking children, showing that, despite size differences, semantic development followed similar paths. For signing children, predicates production appears easier than nominals production compared with hearing children acquiring spoken language. Findings take into account differences in input modalities and language structures.

Deaf children attending different school environments: sign language abilities and theory of mind.

The present study examined whether full access to sign language as a medium for instruction could influence performance in Theory of Mind (ToM) tasks. Three groups of Italian participants (age range: 6-14 years) participated in the study: Two groups of deaf signing children and one group of hearing-speaking children. The two groups of deaf children differed only in their school environment: One group attended a school with a teaching assistant (TA; Sign Language is offered only by the TA to a single deaf child), and the other group attended a bilingual program (Italian Sign Language and Italian). Linguistic abilities and understanding of false belief were assessed using similar materials and procedures in spoken Italian with hearing children and in Italian Sign Language with deaf children. Deaf children attending the bilingual school performed significantly better than deaf children attending school with the TA in tasks assessing lexical comprehension and ToM, whereas the performance of hearing children was in between that of the two deaf groups. As for lexical production, deaf children attending the bilingual school performed significantly better than the two other groups. No significant differences were found between early and late signers or between children with deaf and hearing parents.