A particular strength of the study is the availability of well-validated mental ability test scores at age 11, and the fact that these scores can be compared with the entire population of Scotland born in 1936 and attending schools in Scotland in June 1947. The important domains of cognitive functioning have been examined: reasoning, memory, speed of information processing, and executive function. There are especially rich data on speed of information processing and memory. There are rich data on social and biological factors as possible contributors to individual differences in lifetime cognitive ageing.
