The Flynn effect
Research has uncovered an interesting phenomenon. On average, IQ test scores worldwide have been increasing over time: younger generations perform better than older generations. Per generation, the average IQ test scores increase by 10 points. This is called the Flynn effect, after the researcher who first documented this phenomenon.
Thus it appears that people in 1950 were a lot less smart than they are now, that is if you define intelligence in IQ scores. How is that possible? According to the Flynn effect theory, the increase in IQ scores can in part be ascribed to improvements in education and better nutrition.
In addition, people are reading more, and new technology - computers, Internet - forces people to think more abstractly. All of this leads to an increase in the IQ score.
Reverse Flynn effect?
In the meantime however, there have been studies that indicate the Flynn effect may have ended. Studies in Denmark, Norway and the United Kingdom have shown that the Flynn effect has not only ended, but that there is actually a decrease in the average IQ scores. Convincing explanations for this reversal have not been found yet.