Nonsymbolic Comparison in Deaf Students: No Evidence for a Deficit in Numerosity Processing.

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.

Quantity processing in deaf and hard of hearing children: evidence from symbolic and nonsymbolic comparison tasks.

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.

Differential time course and intensity of PFC activation for men and women in response to emotional stimuli: a functional near-infrared spectroscopy (fNIRS) study.

Using functional near-infrared spectroscopy (fNIRS) we recorded prefrontal cortex (PFC) activation during positive, negative and neutral film clips, based on affective ratings according to their valence and arousal, to assess gender differences in cerebral activation in 15 male and 15 female volunteers. To record PFC activation, five movie clips were presented on a 17-in. TFT screen. The recordings included a pre-stimulus 5-s local baseline and "on" and "off" segments of data, referring to fNIRS Oxy-Hb levels while stimulation (movie clip) was present and during an inter-stimulus blank screen. Our data showed gender differences in the delay period to initial PFC activation and in the course and intensity of activation produced by affective visual stimuli. During the exposure or "on" period of the stimuli we observed more pronounced overshoot and undershoot in men versus women across the range of emotions elicited. This effect was even more pronounced following stimulus cessation ("off" period). The results indicate that gender and the duration of recordings may affect the results of emotional neuroimaging studies.

Contextual interference in learning precision skills.

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.