I'm not sure why the statement should be so controversial. In a cross-sectional study of the current population, every measure but crystallized intelligence pea

I'm not sure why the statement should be so controversial. In a cross-sectional study of the current population, every measure but crystallized intelligence peaked around 25: https://medium.com/psyc-406-2015/how-fast-does-iq-decline-can-you-do-anything-about-it-f5ca370d8b62 https://medium.com/psyc-406-2015/how-fast-does-iq-decline-ca... The second study mentioned in the article, which is longitudinal rather than cross sectional, has more optimistic results for older ages, but as it says, there are problems with tracking the same people over time, such as them just getting better at IQ tests. Regardless, the first, cross-sectional study gives clear answers to the current relation of age to intellectual ability. Age shouldn't be a factor in hiring, only ability, but it's not unreasonable to say that, at least right now, you can expect people in their 20s to perform better at many tasks. It's also hard not to just agree with the "young people are just smarter" statement based on intuition. When have you ever heard of a 20 year old needing help figuring out a television remote? Something clearly changed between the time that someone learned to drive a car and when they had to be shown for the 50th time how to upload a video from their camera to facebook.