To test whether cognitive ability predicts survival from age 79 to 89 years data were collected from 543 (230 male) participants who entered the study at a mean age of 79.1 years. Most had taken the Moray House Test of general intelligence (MHT) when aged 11 and 79 years from which, in addition to intelligence measures at these two time points,…

Modern factor analysis is the outgrowth of Spearman's original "2-factor" model of intelligence, according to which a mental test score is regarded as the sum of a general factor and a specific factor. As early as 1914, Godfrey Thomson realized that the data did not require this interpretation and he demonstrated this by proposing what became…