Chasing Sunset

…more

Is your gym locker room crawling with drug-resistant bacteria? Is the guy with the bulging backpack a suicide bomber? And what about that innocent-looking arugula: Will pesticide residue cause cancer, or do the leaves themselves harbor E. coli? But wait! Not eating enough vegetables is also potentially deadly.

These days, it seems like everything is risky, and worry itself is bad for your health. The more we learn, the less we seem to know—and if anything makes us anxious, it’s uncertainty. At the same time, we’re living longer, healthier lives. So why does it feel like even the lettuce is out to get us?

The human brain is exquisitely adapted to respond to risk—uncertainty about the outcome of actions. Faced with a precipice or a predator, the brain is biased to make certain decisions. Our biases reflect the choices that kept our ancestors alive. But we have yet to evolve similarly effective responses to statistics, media coverage, and fear-mongering politicians. For most of human existence, 24-hour news channels didn’t exist, so we don’t have cognitive shortcuts to deal with novel uncertainties.

Still, uncertainty unbalances us, pitching us into anxiety and producing an array of cognitive distortions. Even minor dilemmas like deciding whether to get a cell phone (brain cancer vs. dying on the road because you can’t call for help?) can be intolerable for some people. And though emotions are themselves critical to making rational decisions, they were designed for a world in which dangers took the form of predators, not pollutants. Our emotions push us to make snap judgments that once were sensible—but may not be anymore.

…more

A funny blog that earns the pee-in-pants worthy award ^_^

There’s a widespread assumption that people’s mental and physical attributes are predictable from their genes. So where does this belief come from, and is it wrong?

People’s understanding of genetic effects is heavily influenced by the way genetics is taught in schools. Mendel and his wrinkly and smooth peas make a nice introduction to genetic transmission, but the downside is that we go away with the idea that genes have an all-or-nothing effect on a binary trait. Some characteristics are inherited this way (more or less), and they tend to be the ones that textbooks focus on: for example eye colour, colour-blindness, Huntington’s disease. But most genetic effects are far more subtle and complex than this. Take height, for instance. Genes are important in determining how tall you are, but this is not down to one gene: instead, there is a host of genes, each of which nudges height up or down by a small amount.

Furthermore, genetic influences may interact in complicated ways. For instance, coat colour in mice is affected by combinations of genes, so that one cannot predict whether a mouse is black, white or agouti (mouse coloured!) just by knowing the status of one gene. The expression of a gene may also depend crucially on the environment; for instance, obesity relates both to calorie intake and genetic predisposition, but the effects are not just additive: some people can eat a great deal without gaining weight, whereas in others, body mass depends substantially on food intake. And a genetic predisposition to obesity can be counteracted by exercise.

This means that we get a very different impression of the strength of genetic influences on a trait if we look at the impact of a person’s whole genome, compared with looking at individual genes in isolation.

…more