ABSTRACT
When using a number of varied mental tests, it is always tempting to guess at the underlying abilities. * For example Word and Information Learning appear to involve memory, and it is easy to assume that they will reflect the emphasis laid by the education system of the country on mechanical learning. Similarly Picture Recognition may be assumed to measure the three-dimensional perception which is necessary, not only for interpreting line drawings, but also for technical jobs. How far it is possible to generalise to abilities in daily life, at school or in jobs can, of course, best be determined by follow-up correlations with external criteria; and most of the tests (or closely similar ones) have been studied in this way in numerous previous researches so that we have a fair idea of what they measure, at least in western cultures. Also the results reported below on group differences, for example the high score of Jamaicans on Word Learning and the low score of Ugandans on Picture Recognition, supply confirmatory evidence, though obviously here one is in danger of arguing in a circle.
