Hemispheric specialization for speech perception in six-year-old black and white children from low and middle socio-economic classes.
| Number | 167 |
|---|---|
| Year | 1974 |
| Drawer | 3 |
| Entry Date | 06/11/1998 |
| Authors | Dorman, M. F. & Geffner, D. S. |
| Contact | |
| Publication | Cortex, 10, 171-176. |
| url | http://www.haskins.yale.edu/Reprints/HL0167.pdf |
| Abstract | [Introduction] On diochotic listening tests with adults, when verbal stimuli are presented simultaneously to the left and right ears, the stimuli presented to the right ear are recalled better than those presented to the left ear (Broadbent and Gregory, 1964; Bryden, 1963; Curry and Rutherford, 1967; Kimara, 1961a; Shankweiler and Studdert-Kennedy, 1967). This right-ear advantage (REA) presumably reflects the functional prepotency of the contralateral auditory pathways and the left hemisphere’s specialization for the perception of speech (Kimura, 1961b; Milner, Taylor and Sperry, 1968; Studdert-Kennedy and Shankweiler, 1970). In children the REA appears to vary as a function of age, sex, and socioeconomic class (SEC) background. Kimura (167) found the low SEC females and high SEC males and females evidence a REA at age five, whereas low SEC males do not evidence a REA until age six. Recently Geffner and Hochberg (171) have reported a large (age) X (SEC) interaction in the development of the REA. Four to seven years old subjects from both low and middle SEC backgrounds were presented a dichotic digits task (cf. Kimura, 1963). The middle SEC subjects evidenced a REA at all ages. The low SEC subjects did not evidence a REA until age seven. These data led Geffner and Hochberg to speculate that children from low SEC backgrounds may not develop left-hemisphere specialization for speech at the same rate as children from more privileged SEC backgrounds. The Geffner and Hochberg data are very striking for they suggest that cortical laterization of function, which has been though to be maturationally determined (Lenneberg, 1967), may be radically slowed down by environmental deficiencies during development. The nature of the environmental conditions which determined the performance of the low SEC subjects is, however, not at all clear. One nonenvironmental variable which may have affected the outcome of the Geffner and Hochberg study was the large proportion of black children in the low SEC group. Conceivably the delayed laterization of speech found for the low SEC population may have been a racial effect interacting with socioenvironmental variables. To clarify the effects of race and SEC as determinates of the REA in children, in the present study, six-year-old black and white children from both low and middle SEC backgrounds were presented a dichotic syllable test (cf. Studdert-Kennedy and Shankweiler, 1970). To minize a possible source experimental bias, the groups children were tested by an examiner of their own race. |
| Notes |
Search Publications