http://www.bbc.co.uk/news/health-13156817 BBC News or 11.04.25 summarizes research showing "IQ tests measure motivation - not just intelligence. Intelligence tests are as much a measure of motivation as they are of mental ability. ...a high IQ score require(s) both high intelligence and high motivation but a low IQ score could be the result of a lack of either factor." The research was done at the University of Pennsylvania (USA).