As I read your question, it seems to me that you are asking about an evolutionary find, and we evolve far too slowly for anyone to say that brains have shrunk from one generation to the next. We do know that human brains are smaller than they were 20,000 years ago. I am not aware of any evidence that would show that my children's brains, for example, are likely to be smaller than mine.
As to whether young people today are not as smart as older people, I think that depends on how one measures this. There are many ways to be smart, and younger people have some advantages, technologically, for example, but in other ways, they seem to have some intellectual advantages, as the previous response suggests.
the electronic addictions, these digital distractions ,whittle away at the intellect of teens and twenty-somethings and could also jeopardize their success in the workplace.The average American youth apparently reads no more than eight minutes a day, but according to Nielsen. Mobile they send an average of 2,272 text messages a month.When a teenager is watching someone stuff a bag of marshmallows in his mouth on You Tube, that stunted intellectual curiosity isn’t the only causality. “We live in a culture where young people — outfitted with phone and laptop and devoting hours every evening from age 10 onward to messaging of one kind and another — are ever less likely to develop the ’silent fluency’ that comes from face-to face interaction,”
Old. Smart. Productive. Rather than being an economic deadweight, the next generation of older Americans is likely to make a much bigger contribution to the economy than many of today's forecasts predict.Many highly educated and well-paid workers -- lawyers, physicians, architects -- already work to advanced ages because their skills are valued. And today's rapid obsolescence of knowledge can actually play to older workers' advantage:
Equally important, high-level work is getting easier for the old. Thanks to medical advances, people are staying healthy, enabling them to work longer than before. Fewer jobs require physically demanding tasks such as heavy lift- ing. And technology -- from memory-enhancing drugs to Internet search engines that serve as auxiliary memories -- will help senior workers compensate for the effects of aging. Better yet, work doesn't feel like a burden to today's fit, older Americans. Many people over 60 don't think of themselves as old.