This increase in IQ scores and the seeming tendency for intelligence levels to increase over time is known as the Flynn effect (named after the late US-born educator, James Flynn). And improvements in health and nutrition, better education and working conditions, along with recent access to technology have all contributed.
While IQ test results have been increasing for some time, research suggesting a “reverse Flynn effect”, indicates this upward trend may now be slowing. A Norwegian study, for example, found that men born before 1975 showed the expected positive “Flynn effect” of a three point gain for each successive decade. But for those born after 1975, there was a steady decline in IQ. This amounts to a seven point difference between generations — with average IQs having dropped by around 0.2 points a year. Other studies carried out between 2005 to 2013 in the UK, Sweden and France have also shown similar results.