No abstract

Deaf Children usually achieve lower scores on numerical tasks than normally hearing peers. Explanations for mathematical disabilities in hearing children are based on quantity representation deficits (Geary, 1994) or on deficits in accessing these representations (Rousselle & Noël, 2008). The present study aimed to verify, by means of symbolic (Arabic digits) and nonsymbolic (dot constellations and hands) magnitude comparison tasks, whether deaf children show deficits in representations or in accessing numerical representations. The study participants were 10 prelocutive deaf children and 10 normally hearing children. Numerical distance and magnitude were manipulated. Response time (RT) analysis showed similar magnitude and distance effects in both groups on the 3 tasks. However, slower RTs were observed among the deaf participants on the symbolic task alone. These results suggest that although both groups’ quantity representations were similar, the deaf group experienced a delay in accessing representations from symbolic codes.

Two experiments using a number matching task (NMT) explored whether two-digit numbers are processed holistically or in a compositional fashion. In the NMT participants are required to decide whether one of the two numbers initially provided (cues) is presented some milliseconds later or not (probe). Probes which have some arithmetic relationship to the cues (e.g., cues: 2 3, probe: 6) are rejected more slowy than probes unrelated to their cues (e.g., cues: 2 3, probe: 7) – interference effect –, and this is considered as evidence of the automatic activation of that arithmetic relationship. Participants were presented with two-digit cues and probes which had an arithmetic progression relationship only detectable once the numbers were decomposed (Experiment 1: cues: 56 7, probe: 89; Experiment 2: cues: 45 67, probe: 89). Results showed longer response times in these conditions compared to unrelated conditions. Data support componential processing even when the numbers to be matched are presented serially.

This research studied the effect of different organisations of practice (blocked and random) on the learning of three different types of throwing. 35 male students practiced three precise throws for 3 wk. Initially the subjects were separated into two groups who trained under different conditions of practice (blocked and random). All subjects improved significantly from initial performance, with both blocked practice and random practice. At the end of acquisition no differences were found between the groups. No significant differences were found on retention tests carried out 48 hr., 4 wk., and 8 wk. after the training period.

It is commonly found that deaf and hard of hearing (DHH) students experience delayed mathematical achievement. The present study used two nonsymbolic comparison tasks to explore the basic numerical skills of DHH students. Nine prelocutive DHH students with cochlear implants and nine hearing students, matched on nonverbal IQ, visual short-term memory, and verbal comprehension, were recruited. The participants performed two different collection comparison tasks with different ratios and under different perceptual conditions. Analyses by task showed similar response times, accuracy, and ratio effects for both groups on the Low Perceptual Condition task, a finding suggesting that the two groups accessed similar representations of quantity. Differences in performance on the simpler High Perceptual Condition task, on which the DHH group showed slower response times, probably were strategic in origin. The results suggest that DHH students have no deficits in basic numerical skills.