READING PERFORMANCE AND VERBAL SHORT-TERM-MEMORY - A TWIN STUDY OF RECIPROCAL CAUSATION

Although a significant relationship between reading performance and ve rbal short-term memory (VSTM) has been well documented, the etiology o f this relationship has not been fully explored. In the study presente d here, the genetic and environmental causes of the phenotypic associa tion between reading and VSTM were analyzed using twin data from the C olorado Reading Project, Results of bivariate behavioral genetic analy ses indicate that both reading ability and VSTM are highly heritable, and that a substantial proportion of their phenotypic correlation is d ue to common genetic influences. Moreover, results of analyses of dire ction of causation suggest that differences in reading performance (or reading component processes) may influence performance on VSTM tasks, but that differences in VSTM are not an important cause of variation in reading performance. However, the possibility of a common cause of both reading performance and VSTM is not precluded.