Smith K, Griffiths P
Neuropsychologia. 1987;25(1B):259-68. doi: 10.1016/0028-3932(87)90136-9.
The performance of dyslexic and control children--matched for age, sex, handedness and performance IQ--was compared on a dichotic listening task in which the stimuli were environmental sounds. Two findings emerged. First, the dyslexic group showed a normal, left ear perceptual advantage for these non-verbal materials. Second, the dyslexics were incapable of occluding dichotically presented sounds to the left ear when required to deploy attention only to sounds entering the right ear. This failure of unilateral selective attention was not found in the controls, nor in either group under a condition of left ear only attention. The data were interpreted as undermining the bihemispheric non-verbal processing hypothesis of developmental dyslexia. It was argued that the dyslexics' apparent inability to override voluntarily the reflexive lateral orienting mechanism was most consistent with explanatory models emphasizing defective functioning, or even malformation, of the left cerebral hemisphere alone.
在一项双耳分听任务中，对诵读困难儿童和对照儿童（在年龄、性别、用手习惯和操作智商方面相匹配）的表现进行了比较，该任务的刺激物为环境声音。出现了两个发现。首先，诵读困难组在这些非语言材料上表现出正常的左耳感知优势。其次，当要求诵读困难儿童仅将注意力集中于进入右耳的声音时，他们无法遮蔽左耳接收到的双耳分听声音。对照组未发现这种单侧选择性注意力的缺失，在仅左耳注意的条件下，两组也均未出现这种情况。这些数据被解释为对发育性诵读困难的双半球非语言加工假说不利。有人认为，诵读困难儿童明显无法自主超越反射性的侧向定向机制，这与仅强调左脑半球功能缺陷甚至畸形的解释模型最为一致。
