Experiments dating back to the 1960s show people have less of a reaction to viewing an unpleasant image or experiencing an electric shock when they know it’s coming than when they’re not expecting it.

Orthorexia nervosa, the “health food eating disorder”, gets its name from the Greek word ortho, meaning straight, proper or correct.

This exaggerated focus on food can be seen today in some people who follow lifestyle movements such as “raw”, “clean” and “paleo”.

American doctor Steven Bratman coined the term “orthorexia nervosa” in 1997 some time after his experience in a commune in upstate New York.

It was there he developed an unhealthy obsession with eating “proper” food:

In light of the news of another tragic airline crash, and following in the wake of several other high profile air disasters, it might be natural to ask whether air travel is becoming less safe.

In fact, according to the numbers, air travel is safer than at almost any point in the history of commercial flight.

While the number of fatalities in some recent crashes has been high, the number of overall fatal accidents in recent years has dropped to its lowest point since the dawn of the jet age. Also, as more and more people take to the skies each year, the numbers of fatalities per liftoff or per flight hour have also dropped dramatically.

On Monday, Cameron revealed that he would not be seeking a third term as PM.

He chose an informal interview with the BBC’s deputy political editor, James Landale, as the platform for his surprise announcement.The announcement caused feverish media speculation about his motivation for dropping this political bombshell, and the consequences for the electoral fortunes of the Conservative Party.

Do you ever have trouble telling right from left? For example, you’re taking a driving lesson and the instructor asks you to take a left turn and you pause, struggling to think of which way is left.

If so, you’re not on your own – a significant proportion of our population has difficulty in telling right from left.

Mention the terms “intellectual giftedness” and “learning disability” and there is a general understanding of what each term means. However, most people are unaware that in many circumstances the two can go hand in hand.

Current US research suggests that 14% of children who are identified as being intellectually gifted may also have a learning disability. This is compared to about 4% of children in the general population. No-one has been able to explain this discrepancy.