10 April

Another one of the interesting myths that live with us. Average life expectancy. You can ask just about anyone, and they'll tell you that we live much longer today than our ancestors, mostly due to advances in marvellous modern medicine. It's not true. And it's not even true that people in rich countries today live longer than people in poor countries. We're just bad at maths. Average life expectancy is the average number of years a newborn baby can be expected to live in a given society. Why our *average* life expectancy in the Western world looks like it's grown so much is because our babies don't die like they used to. They're not living to much older ages as adults, they're just surviving to adulthood in much greater numbers. We forget about averages. A person who reaches 65 today is not much more likely to live to 100 than a person who reached 65 500 years ago. There aren't a whole lot of 100+ year old people around, at any time in human history. This myth is a hard one for people to dump though, because it's one of the ways they think the modern world is special, that we're smarter now and our knowledge has helped us live longer. For example if you say to people that our ancestors ate lots of fat and salt, they will say "yes but they lived to about 35, didn't they?" And there's the bad maths, and the myth.