There are some cultures that revere elders. America clearly isn't one of them. From VCs who publicly proclaim that anyone over 30 is past their sell-by date to celebrities who, thanks to the miracles of plastic surgery, seem stuck in ageless amber, our culture communicates that getting older is something to dread.

We don't get dumber as we age.

We might pay lip service to the wisdom of seniors, but as we get older and start losing our keys and forgetting where we parked more, many of us worry about what the passing of the years is doing to our brains. We shouldn't, Kaufman insists, rounding up a ton of fascinating studies that show while age changes our intelligence, it doesn't lessen it. 

Yes, disease and dementia are legitimate sources of concern. But if you think the natural course of aging makes us dumber, you haven't read the latest research. What scientists have found is that different aspects of intelligence peak at different ages. And some important aspects of intelligence just keep going up as long as your brain stays healthy.

For instance, one series of studies looking at more than 40,000 people found that while our memories for personal stories peak around high school (which is part of the reason we have a so-called "reminiscence bump" for the memories of our teens), visual-spatial skills don't start to decline until your 30s, and your vocabulary keeps growing into your 40s.

What about middle age and beyond? Are there aspects of intelligence that just keep increasing? Yup, answers Kaufman, though not necessarily ones captured by IQ tests.

These tests, designed specifically with young people in mind, measure our ability to learn new information, not how much we already know. As you'd expect, the body of knowledge stored in your brain continues to grow throughout your life. Call it wisdom, call it street smarts, or call it just plain smarts, but research shows you continue stockpiling it as the years rolls on, which means you just keep getting more intelligent by this important measure. (The one exception seems to be highly technical scientific knowledge in fields like chemistry and physics, which peaks earlier in life.)

Intelligence doesn't peak. It changes. 

The takeaway, according to Kaufman, should cheer anyone aiming to stay as sharp as ever as you age.

"It seems that the question 'When does intelligence peak?' is actually a rather meaningless question," he concludes. "Not only do our various cognitive functions peak at different times, but past a certain age it might make more sense to view adult intelligence not through the lens of youthful general processing speed and reasoning, but through the lens of expertise, wisdom, and purpose."