Behavioral and molecular genetic research has established that child cognitive ability and academic performance are substantially heritable, but genetic variation does not account for all of the stratification of cognitive and academic outcomes across families. Which specific contexts and experiences contribute to these "shared…

Aging-related declines occur in many different domains of cognitive function during middle and late adulthood. However, whether a global dimension underlies individual differences in changes in different domains of cognition and whether global genetic influences on cognitive changes exist is less clear. We addressed these issues by applying…

Recent work with the 42 mental ability tests administered to participants of the Minnesota Study of Twins Reared Apart (MISTRA) has suggested that there are important dimensions of mental ability that function independently of "g". Two of these dimensions, rotation-verbal and focus-diffusion, appear to involve trade-offs: greater…

Background: Children who meet language test criteria for specific language impairment (SLI) are not necessarily the same as those who are referred to a speech and language therapist. Aims: To consider how far this discrepancy reflects insensitivity of traditional language tests to clinically important features of language impairment. Methods &…