How much can you expect from a septuagenarian brain?

A special issue on neuroscience and neuroculture.
April 26 2007 6:47 PM

How Smart Is Grandpa?

How much can you expect from a septuagenarian brain?

John McCain. Click image to expand.
Sen. John McCain, R-Ariz.

Sen. John McCain announced his intent to run for president in 2008 on Wednesday. If elected, he would take office at age 72, the oldest first-time president ever to do so. "I'm not the youngest candidate. But I am the most experienced," he said during a speech in Portsmouth, N.H. Just how much can you expect from a typical septuagenarian brain?

It depends on the septuagenarian. Visual-spatial skills—like those involving hand-eye coordination—often deteriorate first, typically before the age of 40. While politicians don't need to have a killer tennis serve, they do need to learn new things, and retain them in short-term and intermediate memory. Those abilities are usually the next to decline. On average, people lose about a fifth of their working memory capacity between the ages of 40 and 70. But the loss of mental function varies widely among individuals—from as little as 3 percent to as much as 50 percent—and is greatly affected by disease. After memory begins to slip away, we gradually lose the ability to make good decisions based on new information. (Septuagenarians who start with high cognitive function—like McCain, perhaps—are less likely to experience mental deterioration as they age.)


Older people develop ways to compensate for their mental decline, such that many can function just as well as the young. Someone who's 60 might take a bit longer to process information than a 40-year-old, but he might find new ways to perform the same cognitive task. (He might rely more on past experience, for example.) That can explain why many CEOs and doctors peak in middle age, when they have a healthy balance between their capacity for learning and their life experience. Ronald Reagan's superb communication skills, for instance, helped him compensate for presidential gaffes—like toasting "the people of Bolivia" while at a banquet in Brazil.

Bonus Explainer: So what exactly does aging do to the brain? The connections between cells start to break down. You don't have to worry about losing whole neurons, since most brain cells stick around, and the ones that die don't have much of an effect. But researchers have found that we lose synapses as we get older. Advancing age also causes a deterioration of each cell's insulating layer, called the myelin sheath. With age, the myelin loosens, which slows down the electrical transmission of nerve impulses from one cell to the next.

Got a question about today's news? Ask the Explainer.

Explainer thanks Amy Arnsten of Yale University and John Morley of Saint Louis University School of Medicine.

Michelle Tsai is a Beijing-based writer working on a book about Chinatowns on six continents. She blogs at



Smash and Grab

Will competitive Senate contests in Kansas and South Dakota lead to more late-breaking races in future elections?

Stop Panicking. America Is Now in Very Good Shape to Respond to the Ebola Crisis.

The 2014 Kansas City Royals Show the Value of Building a Mediocre Baseball Team

The GOP Won’t Win Any Black Votes With Its New “Willie Horton” Ad

Sleater-Kinney Was Once America’s Best Rock Band

Can it be again?


Forget Oculus Rift

This $25 cardboard box turns your phone into an incredibly fun virtual reality experience.

One of Putin’s Favorite Oligarchs Wants to Start an Orthodox Christian Fox News

These Companies in Japan Are More Than 1,000 Years Old

Trending News Channel
Oct. 20 2014 6:17 PM Watch Flashes of Lightning Created in a Lab  
  News & Politics
Oct. 20 2014 8:14 PM You Should Be Optimistic About Ebola Don’t panic. Here are all the signs that the U.S. is containing the disease.
Oct. 20 2014 7:23 PM Chipotle’s Magical Burrito Empire Keeps Growing, Might Be Slowing
Oct. 20 2014 3:16 PM The Catholic Church Is Changing, and Celibate Gays Are Leading the Way
  Double X
The XX Factor
Oct. 20 2014 6:17 PM I Am 25. I Don't Work at Facebook. My Doctors Want Me to Freeze My Eggs.
  Slate Plus
Tv Club
Oct. 20 2014 7:15 AM The Slate Doctor Who Podcast: Episode 9 A spoiler-filled discussion of "Flatline."
Brow Beat
Oct. 20 2014 9:13 PM The Smart, Talented, and Utterly Hilarious Leslie Jones Is SNL’s Newest Cast Member
Oct. 20 2014 11:36 PM Forget Oculus Rift This $25 cardboard box turns your phone into an incredibly fun virtual-reality experience.
  Health & Science
Bad Astronomy
Oct. 21 2014 7:00 AM Watch the Moon Eat the Sun: The Partial Solar Eclipse on Thursday, Oct. 23
Sports Nut
Oct. 20 2014 5:09 PM Keepaway, on Three. Ready—Break! On his record-breaking touchdown pass, Peyton Manning couldn’t even leave the celebration to chance.