The development of haptic processing skills from childhood to adulthood by means of two-dimensional materials.

Research into haptic perception has mostly focused on 3-dimensional objects, and more needs to be known about the processing of 2-dimensional materials (e.g., raised dots and lines and raised-line shapes, patterns and pictures). This study examines the age-related changes in various skills related to the haptic exploration of 2-dimensional raised-line and dot materials and how these skills are related to haptic picture perception. Ninety-one participants, aged 4 years to adult, were asked to perform a series of haptic tasks that entailed (a) finding dots and following lines; (b) matching elements based on texture, shape, and size; (c) matching elements based on spatial location and orientation; (d) memorising sequences of dots and shapes; and (e) identifying complete and incomplete raised-line pictures. On all the tests, the results showed that scores improved with age. Shape discrimination scores accounted for variability in comprehension scores for outline pictures. We suggested that identifying tactile pictures by touch improved with age and mainly depended on the improvement of shape discrimination skills. (PsycINFO Database Record

Haptic-2D: A new haptic test battery assessing the tactual abilities of sighted and visually impaired children and adolescents with two-dimensional raised materials.

To fill an important gap in the psychometric assessment of children and adolescents with impaired vision, we designed a new battery of haptic tests, called Haptic-2D, for visually impaired and sighted individuals aged five to 18 years. Unlike existing batteries, ours uses only two-dimensional raised materials that participants explore using active touch. It is composed of 11 haptic tests, measuring scanning skills, tactile discrimination skills, spatial comprehension skills, short-term tactile memory, and comprehension of tactile pictures. We administered this battery to 138 participants, half of whom were sighted (n=69), and half visually impaired (blind, n=16; low vision, n=53). Results indicated a significant main effect of age on haptic scores, but no main effect of vision or Age × Vision interaction effect. Reliability of test items was satisfactory (Cronbach's alpha, α=0.51-0.84). Convergent validity was good, as shown by a significant correlation (age partialled out) between total haptic scores and scores on the B101 test (rp=0.51, n=47). Discriminant validity was also satisfactory, as attested by a lower but still significant partial correlation between total haptic scores and the raw score on the verbal WISC (rp=0.43, n=62). Finally, test-retest reliability was good (rs=0.93, n=12; interval of one to two months). This new psychometric tool should prove useful to practitioners working with young people with impaired vision.

Haptic identification of raised-line drawings when categorical information is given: A comparison between visually impaired and sighted children

Research into haptic picture perception has mostly concerned adult participants, and little is known about haptic picture perception in visually impaired and sighted children. In the present study, we compared 13 visually impaired children (early blind and low vision) aged 9-10 years and 13 agematched blindfolded sighted children on their ability to identify raised-line pictures of common objects when information about object category was provided prior to picture presentation (semantic cueing). The visually impaired children had moderate practice with tactile pictures, whereas the sighted controls had no prior practice with tactile pictures. We sought to determine whether the benefits of semantic cueing would add to those of practice, resulting in higher performance in the visually impaired children compared to the sighted controls (hypothesis 1), or whether semantic cueing would compensate for the lack of practice with tactile pictures in the sighted children, leading to a possible disappearance of the advantage of the visually impaired children over the sighted controls (hypothesis 2). In line with hypothesis 1, the results showed that the visually impaired children outperformed the sighted controls on both identification accuracy and response time to correct naming. We concluded that the visually impaired children outperformed the sighted controls because they benefited from both semantic cueing and superior exploration skills. By contrast, in the sighted children, semantic cueing was not sufficient to compensate for their encoding difficulties (AU)

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