The study of twins / Peter Mittler.

  • Mittler, Peter J.
Date:
[1971]
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The study of twins / Peter Mittler. Source: Wellcome Collection.

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    I 35 Language were tested as part of a national programme of achievement testing throughout the whole of Sweden during 1959. Mean scores for twins were significantly below the means for non- twins on reading, writing and arithmetic tests. Examination of the distribution of test scores led Husén to the conclusion that the lower means among twins were due not only to a higher frequency of low scores, as sug¬ gested, for example, by his previous studies (1953), but also to a correspondingly lower frequency of high scores. Language The first systematic study of language abilities in young twins was reported by Day (1932); she used a series of ad hoc language tests, relying on the pioneer studies of Dorothea McCarthy (1930) - chiefly mean length of res¬ ponse, ratings of grammatical complexity and measures of egocentric and socialized speech (based on Piaget, 1926). Her study demonstrated a clear and striking inferiority of twins compared to singleton controls. Twins showed an overall poverty and reduction of vocabulary, used more immature and primitive sentence constructions and showed a more limited range of those parts of speech which contri¬ bute to cognitive operations involving classification, abstrac¬ tion and conceptualization. Moreover, Day showed that their inferiority on language tests was relatively much greater than that shown on tests of general intelligence, and that their linguistic inferiority increased rather than de¬ creased between two and five years of age. Similar findings were reported by Koch (1966) on the verbal sections of the Primary Mental Abilities tests. Davis (1937), who extended the earlier study by Day, found that twins approximate more closely to normal language development as they become older, though it is difficult to distinguish the efifect of age from that of exposure to school. A recent study by the writer (Mittler, 1969a, 1970c) com¬ pared the performance of 200 four-year-old twins and 100