- Email: [email protected]
Developmental divided visual field studies: A new task and strategy analysis
TENNET I
597
direction of hand movement from the direction of visual and representational space exploration. The experiments were conducted on 40 patients with right hemisphere lesions, 28 of whom exhibited a mild, moderate, or severe degree of neglect, categorized according to performance on a standard clock drawing task. There was a control group of 14 neurologically intact subjects. Two main results emerged from the study: (1) Direction of hand movement is not a significant factor for any group of subjects, which means that hypokinesia is not implicated in the neglect syndrome. (2) The direction of search for concealed clock numerals revealed a distorted underlying representation, topologically consistent with the distortions observed on the actual clock drawings. Evidence of systematic distortion of mental representation is theoretically significant because it suggests that the core deficits in neglect do not stem from a motor disorder, nor from a truncated spatial representation, but rather from a flawed reconstruction of space, executed with the limited spatial capacities of the undamaged left hemisphere. Divided Visual Field Studies: A New Task and Strategy Analysis. PIERRE CORMIERAND CAROLTOMLINSON-KEASEY, Department of Psychology, Izaak Walton Killam Children’s Hospital, Halifax, Nova Scotia.
13. Developmental
A review of the literature following a new task and strategy analysis is presented. This review stresses that reading is the global verbal task tested by visual field studies. In contrast to previous literature, breaking down the literature by stimulus type (word and letter processing) leads to observe a developmental pattern. The pattern of visual field advantages is seen as different for each stimulus type: absence of any advantage to right visual field advantages for words and shifts from left to right visual field advantages for letters. In this literature, extensive task analyses have not been conducted by preliminary results indicate developmental changes in the way children’s attention is focused on the task and in the way they process different requirements of a task. It is concluded that future research should test component processes of reading in young readers and how cognitive variables affect these component processes at different ages. 14. The Effect of Eliciting Manual Interference.
Visual Imagery with Sentences vs. Object Sounds on Lateralized
HENRIETTALEMPERT,Psychology Department, University of Toronto, Toronto, Ontario.
Previous studies have shown that imaging SVO sentences disrupts concurrent right-hand action disproportionately, relative to silently rehearsing the sentences. Does this imply that imaging verbal material disproportionately increases demands on left hemisphere (LH) resources, or that the manual interference paradigm is unable to detect right hemisphere (RH) load? These possibilities were tested by a within-subjects design in which righthanders (24 women, 16 men) performed two different imagery tasks during unimanual tapping. On sentence imagery trials, they imaged SVO sentences. On contro1 trials, they heard object sounds and imaged the object that produced the sound. The latter task was selected because the left ear advantage for recognizing object sounds implies that it has an RH component(s). Right-lateralized manual decrement occurred for sentences and symmetrical decrement for sounds. More critically, left-hand decrement was significantly greater for sounds than sentences, whereas right-hand decrement was comparable for the two tasks. The fact that the RH component(s) of the control task disrupted left-hand action implies that the right-lateralized manual interference for imaging sentences can now be attributed to greater LH than RH involvement. 15. Is There a Fixed Neural Substrate for Tonal Organization of Pitch? Laterality Effects Point toward a Left-Hemispheric Locus. ISABELLEPERETZ,Department of Psychology,
University of Montreal, Montreal, Quebec.
597
direction of hand movement from the direction of visual and representational space exploration. The experiments were conducted on 40 patients with right hemisphere lesions, 28 of whom exhibited a mild, moderate, or severe degree of neglect, categorized according to performance on a standard clock drawing task. There was a control group of 14 neurologically intact subjects. Two main results emerged from the study: (1) Direction of hand movement is not a significant factor for any group of subjects, which means that hypokinesia is not implicated in the neglect syndrome. (2) The direction of search for concealed clock numerals revealed a distorted underlying representation, topologically consistent with the distortions observed on the actual clock drawings. Evidence of systematic distortion of mental representation is theoretically significant because it suggests that the core deficits in neglect do not stem from a motor disorder, nor from a truncated spatial representation, but rather from a flawed reconstruction of space, executed with the limited spatial capacities of the undamaged left hemisphere. Divided Visual Field Studies: A New Task and Strategy Analysis. PIERRE CORMIERAND CAROLTOMLINSON-KEASEY, Department of Psychology, Izaak Walton Killam Children’s Hospital, Halifax, Nova Scotia.
13. Developmental
A review of the literature following a new task and strategy analysis is presented. This review stresses that reading is the global verbal task tested by visual field studies. In contrast to previous literature, breaking down the literature by stimulus type (word and letter processing) leads to observe a developmental pattern. The pattern of visual field advantages is seen as different for each stimulus type: absence of any advantage to right visual field advantages for words and shifts from left to right visual field advantages for letters. In this literature, extensive task analyses have not been conducted by preliminary results indicate developmental changes in the way children’s attention is focused on the task and in the way they process different requirements of a task. It is concluded that future research should test component processes of reading in young readers and how cognitive variables affect these component processes at different ages. 14. The Effect of Eliciting Manual Interference.
Visual Imagery with Sentences vs. Object Sounds on Lateralized
HENRIETTALEMPERT,Psychology Department, University of Toronto, Toronto, Ontario.
Previous studies have shown that imaging SVO sentences disrupts concurrent right-hand action disproportionately, relative to silently rehearsing the sentences. Does this imply that imaging verbal material disproportionately increases demands on left hemisphere (LH) resources, or that the manual interference paradigm is unable to detect right hemisphere (RH) load? These possibilities were tested by a within-subjects design in which righthanders (24 women, 16 men) performed two different imagery tasks during unimanual tapping. On sentence imagery trials, they imaged SVO sentences. On contro1 trials, they heard object sounds and imaged the object that produced the sound. The latter task was selected because the left ear advantage for recognizing object sounds implies that it has an RH component(s). Right-lateralized manual decrement occurred for sentences and symmetrical decrement for sounds. More critically, left-hand decrement was significantly greater for sounds than sentences, whereas right-hand decrement was comparable for the two tasks. The fact that the RH component(s) of the control task disrupted left-hand action implies that the right-lateralized manual interference for imaging sentences can now be attributed to greater LH than RH involvement. 15. Is There a Fixed Neural Substrate for Tonal Organization of Pitch? Laterality Effects Point toward a Left-Hemispheric Locus. ISABELLEPERETZ,Department of Psychology,
University of Montreal, Montreal, Quebec.