The reproduction of vertical and oblique orientations in the visual, haptic, and somatovestibular systems

This study investigates whether the vertical orientation may be predominantly used as an amodal reference norm by the visual, haptic, and somato-vestibular perceptual systems to define oblique orientations. We examined this question by asking the same sighted adult subjects to reproduce, in the frontal (roll) plane, the vertical (0°) and six oblique orientations in three tasks involving different perceptual systems. In the visual task, the subjects adjusted a moveable rod so that it reproduced the orientation of a visual rod seen previously in a dark room. In the haptic task, the blindfolded sighted subjects scanned an oriented rod with one hand and reproduced its orientation, with the same hand, on a moveable response rod. In the somato-vestibular task, the blindfolded sighted subjects, sitting in a rotating chair, adjusted this chair in order to reproduce the tested orientation of their own body. The results showed that similar oblique effects (unsigned angular error difference between six oblique orientations and vertical orientation) were observed across the three tasks. However, there were no positive correlations between the visual, haptic,     

The Case of the Vanishing Optimum

It is not only people who may disappear, nor one's keys. It may also be the optimum that one was so certain of being able to grasp and that so suddenly reveals itself to be totally elusive. And the situation then becomes dramatic, as with people, or utterly confused, as with the loss of keys: a familiar element is suddenly missing and one does not know how, nor where, to look for it. However, in contrast with the disappearance of a person that provokes action based on rational behaviour—notification of the police, broadcasting of a notice of search—the disappearance of the optimum begets reactions that are unpredictable, irrational or even ideological. Instead of its absence being accepted and action taken accordingly, its absence is denied. Why does the optimum vanish under certain conditions? And why does one not accept to admit that fact? Those are the two questions that we shall examine. We shall start with the second one, which presents a more straightforward approach to the problem.     

The effects of literacy on the recognition of dichotic words

The hypothesis that awareness of phonemic segments influences the way in which speech is perceived was examined. Illiterate adults, who generally lack awareness of segments, were compared with literates, who are aware of the segmental structure of speech, on the recognition of words presented dichotically. A group of people who learned to read and write but who do it only occasionally was also tested. The results indicated much better performance in literates than in illiterates or semiliterates. In addition, literates made proportionally more single-segment errors, especially those limited to the first consonant, and fewer global errors, i.e. on all the segments of a syllable, than illiterates. On the other hand, phonetic feature blendings were as frequent in illiterates as in literates. It is suggested that awareness of segments allows attention to be focused on the phonemic constituents of speech and thus contributes to better recognition in difficult listening conditions. However, awareness of segments does not influence the preattentive extraction of phonetic information.

The hypothesis that awareness of phonemic segments influences the way in which speech is perceived was examined. Illiterate adults, who generally lack awareness of segments, were compared with literates, who are aware of the segmental structure of speech, on the recognition of words presented dichotically. A group of people who learned to read and write but who do it only occasionally was also tested. The results indicated much better performance in literates than in illiterates or semiliterates. In addition, literates made proportionally more single-segment errors, especially those limited to the first consonant, and fewer global errors, i.e. on all the segments of a syllable, than illiterates. On the other hand, phonetic feature blendings were as frequent in illiterates as in literates. It is suggested that awareness of segments allows attention to be focused on the phonemic constituents of speech and thus contributes to better recognition in difficult listening conditions. However, awareness of segments does not influence the preattentive extraction of phonetic information.