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The role of attention in the processing of pictures and words was investigated for a group of normally achieving children and for groups of learning disability sub-types that were defined by deficient performance on tests of reading and spelling (Group RS) and of arithmetic (Group A). An event-related potential (ERP) recording paradigm was employed in which the children were required to attend to and name either pictures or words that were presented individually or in superimposed picture-word arrays that varied in degree of semantic relation. For Group RS, the ERP waves to words, both presented individually or attended in the superimposed array, exhibited reduced N450 amplitude relative to controls, whereas their ERP waves to pictures were normal. This suggests that the word-naming deficiency for Group RS is not a selective attention deficit but rather a specific linguistic deficit that develops at a later stage of processing. In contrast to Group RS and controls, Group A did not exhibit reliable early frontal negative waves (N280) to the super-imposed pictures and words, an effect that may reflect a selective attention deficit for these children that develops at an early stage of visuo-spatial processing. These early processing differences were also evident in smaller amplitude N450 waves for Group A when naming either pictures or words in the superimposed arrays.

The present paper has two objectives: (1) a critical review of dichotic listening studies in children, and (2) an investigation of developmental parameters of the ear asymmetry, based on factors revealed in the review. A dichotic listening task was administered to approximately 20 boys and 20 girls at each of five ages (5,6,7,9 and 11). The results were as follows: (1) significant ear asymmetry was not found in children younger than nine years of age; (2) the magnitude of the differences between ears, while not significant until age nine, continued to increase with age until eleven at which time the slope functions for each ear plateaued; and (3) ear asymmetry was independent of sex. An attempt is made to explain the present results, and those of previous research, within a developmental framework.

The longitudinal development of ear asymmetry has been investigated in two samples of kindergarten and primary school children over an age range of six years. Ear preference in a dichotic digit test, administered four times, did not appear to be affected by age and sex: right ear advantage was predominant at all times. Individual comparison showed the development of ear advantage to depend on initial preference. Initially left eared subjects when changing ear advantage do so from left to right at early and from right to left at later school ages. The left-right shift may be due to the school teaching of linguistic skills which could selectively activate the left cerebral hemisphere. This explanation is supported by the finding that initially right eared subjects tended to conserve that preference at early school ages. Acknowledgements. We would like to thank Mr. P. Borgman and his staff of the Johannesschool in Amsterdam as well as their pupils who did not protest despite being examined year after year. The cooperation of the Free University Audio-Visual Center (Mr. Fred Van Hilst) is kindly acknowledged. Finally we would like to thank Dr. Paul Harris who was willing to read the English text critically and all others who assisted in the completion of this research.

Dichotic listening research with children has continued to be prevalent although numerous authors have described both theoretical and methodological limitations with traditional dichotic listening free-recall paradigms. The present research adds to this growing skepticism by reanalyzing two major longitudinal studies of children's ear asymmetries. These two studies, based in different countries (United States, Holland), utilized highly similar paradigms (free-recall digits), subjects (males), and age levels (kindergarten and second and fifth grade). The questions of ear advantage development, patterns of ear advantages, and the relationship between dichotic listening performance and reading skills are addressed from the multiple statistical methodologies represented in the literature. From these analyses, support for all of the major hypotheses regarding the developmental patterns of dichotic listening performances could be obtained from the same data samples. The use of traditional free-recall dichotic listening paradigms are not recommended for use with children. The implications for future research are discussed.

Two, three and four pair dichotic digit tests were presented twice to 250 normal kindergarten and primary school children. Test-retest as well as inter-test reliability and consistency coefficients were calculated. Their values were shown to match similar indices found in normal adults.