In the 1980s, James R. Flynn and Richard Lynn examined psychometric data and discovered evidence that the IQ scores of Americans were increasing significantly between the early 1930s and late 1970s. On average, younger cohorts scored higher than their elders. This was confirmed by later studies and on data in other countries; the discovery became known as the Lynn-Flynn effect or simply the Flynn effect. However, the Flynn effect is not due to increases in general intelligence but rather because people were becoming more adept at specific tasks, especially in scientific or analytical thinking. This is due to having improved nutrition, higher literacy rates, better educational opportunities, and generally a more intellectually stimulating environment, all of which were made possible by rising standards of living. Put another way, the modern world forces people to put on what Flynn called "scientific spectacles" or think in more abstract ways and better prepare themselves for exams. According to Flynn, the growing importance of education and cognitive abilities could be traced back to the Industrial Revolution, which resulted in formal education becoming vital and the shrinking of family sizes, making it possible for parents to invest more in their children. Family size had been falling across the Western world during the twentieth century.