Researchers suggest the reason older people appear to be getting smarter is higher education rates and increased use of technology.
However, the same cannot be said for older people's physical and mental health, which appears to be declining.
The findings come from two studies: one that measured cognitive function, physical fitness and mental health in people over the age of 50 in Germany, and another that measured cognitive function in the over-50s in England and Germany.
Both studies - one published in PLOS ONE and the other in the journal Intelligence - are the work of researchers from the International Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria.
The first study analyzes data from representative surveys of men and women aged 50-90 living in Germany in 2006 and 2012. The data include results of tests of cognitive processing speed, physical fitness and mental health.
The results show that men and women of all ages from 50-90 performed better on cognitive tests in 2012 than in 2006, but physical functioning and mental health declined - especially in men aged 50-64 with low education.
On average, test scores of people aged 50 and over in the later survey correspond to test scores from people between 4-8 years younger who were tested 6 years earlier.
The second study shows that a similar improvement in cognitive function can be seen in older people in England. The study also surveyed people's use of personal computers and mobile phones.
Cognitive and physical fitness are diverging in older people
The results are important because while previous studies have shown today's elderly population finds itself generally in better condition, both cognitively and physically, than previous generations -"60 is the new 40" as the saying goes - they are the first to suggest the two trends may be diverging.
Changing lifestyles may be behind these divergent results, says Nadia Steiber, IIASA researcher and assistant professor in the department of economic sociology at the University of Vienna, who wrote the first paper and co-authored the other. She explains:
"Life has become cognitively more demanding, with increasing use of communication and information technology also by older people, and people working longer in intellectually demanding jobs. At the same time, we are seeing a decline in physical activity and rising levels of obesity."
Both studies appear to confirm what researchers refer to as the "Flynn effect," where test scores suggest IQ is rising from generation to generation.
While rising education levels may offer a partial explanation, they do not explain the whole effect, the researchers state. In the second study, for example, the authors note that the results "provide evidence for the existence of a Flynn effect on 50+ year olds which remains constant over age and education."
They conclude the use of modern technology - such as computers and mobile phones - in the first decade of the 2000s may for the first time be contributing to the Flynn effect.
Findings from these studies apply to Germany and England, the researchers point out, and future studies may well find similar patterns in other countries.
The research forms part of the Re-Aging Project (Reassessing Aging from a Population Perspective), which is being funded by the European Research Council. The Re-Aging Project is developing new ways to study and think about age and aging in the 21st century, as the following video explains.
Meanwhile, Medical News Today learned of a recent report commissioned by the UK government that suggests digital technology both helps and harms older people's social lives. The report was produced by the London School of Economics and Political Science and finds that nearly 5 million people over the age of 64 in the UK do not have Internet skills.
The report suggests there are major challenges to helping older people stay connected in an increasingly digital world, as traditional ways of staying in touch with distant friends and family are overtaken by online tools such as Skype, social networking and email.