IQ scores have risen sharply over the past decades．"This (62) our belief about the (63) of IQ, "says psychologist Ulrich Neisser of Cornell University． "It’s in evidence that you can indeed change it．" There’s just one little problem．Leaving aside for the very real question of (64) IQ is truly a proxy(代表)for intelligence, scientists can’t explain what has made IQ scores increases．Neither nature (65) nurture answers the question, for different reasons．Lots of data, from twin studies to adoption research, suggests that genes (66) some 75 percent of the difference between individuals’IQ by late adolescence．Psychologists who study intelligence mostly agree that hereditary factors (67) the lion’s share of IQ difference． "It’s been a (68) ", says William Dickens of the Brookings Institution．"The high inheritability of IQ suggests that environment is (69) powerful．"To (70) the mystery, Dickens (71) up with James Flynn, who in 1987 discovered the IQ rise, now called the Flynn effect．In a study being published this week in Psychological Review, the duo offer an explanation that not only might (72) the paradox but may also (73) on the forces that (74) intelligence．"People’s IQs are affected by both environment and genes, but their environments are matched to their IQs, "the researchers conclude． (75) genes do indeed have an important effect：they cause people to seek out certain environments and life experiences．If you have a biological (76) in intelligence, you will likely enjoy school, books, puzzles, asking questions and thinking abstractly, all of which will tend to (77) your innate brainpower．"Higher IQ leads one into better environments, causing still higher IQ, "says Dickens and Flynn． (78) multiplier effect(倍数效应), you will likely study even more, haunt the library, pester(纠缠)adults with questions and choose bright peers as friends, boosting your intelligence yet again． As far as scientists can tell, experiences that (79) the intelligence of someone born with an IQ edge have just about the same (80) effect on people of average intelligence．In other words, whether you seek out an IQ—boosting environment or whether it finds you (81) no difference．In either case, experiences and the social and technological surround should work their magic．This effect may account for the IQ rise over the decades．