The world’s oldest form of resistance training A  From the very first caveman to scale a tree or hang from a cliff face, to the mighty armies of the Greco-Roman empires and the gymnasiums of modern American high schools, calisthenics has endured and thrived because of its simplicity and utility. Unlike strength training which involves weights, machines or resistance bands, calisthenics uses only the body’s own weight for physical development. B  Calisthenics enters the historical record at around 480 B.C., with Herodotus’ account of the Battle of Thermopylae. Herodotus reported that, prior to the battle, the god-king Xerxes sent a scout party to spy on his Spartan enemies. The scouts informed Xerxes that the Spartans, under the leadership of King Leonidas, were practicing some kind of bizarre, synchronized movements akin to a tribal dance. Xerxes was greatly amused. His own army was comprised of over 120,000 men, while the Spartans had just 300. Leonidas was informed that he must retreat or face annihilation. The Spartans did not retreat, however, and in the ensuing battle they managed to hold Xerxes’ enormous army at bay for some time until reinforcements arrived. It turns out their tribal dance was not a superstitious ritual

A Throughout history, there have been instances in which people have been unwilling to accept new theories, despite startling evidence. This was certainly the case when Copernicus published his theory – that the earth was not the center of the universe. B  Until the early 16th century, western thinkers believed the theory put forward by Ptolemy, an Egyptian living in Alexandria in about 150 A.D. His theory, which was formulated by gathering and organizing the thoughts of the earlier thinkers, proposed that the universe was a closed space bounded by a spherical envelope beyond which there was nothing. The earth, according to Ptolemy, was a fixed and immobile mass, located at the center of the universe. The sun and the stars revolved around it. C  The theory appealed to human nature. Someone making casual observations as they looked into the sky might come to a similar conclusion. It also fed the human ego. Humans could believe that they were at the center of God’s universe, and the sun and stars were created for their benefit. D  Ptolemy’s theory was, of course, incorrect, but at the time nobody contested it. European astronomers were more inclined to save face. Instead of proposing

A It has long been held that decisions made collectively by large groups of people are more likely to turn out to be accurate than decisions made by individuals. The idea goes back to the ‘jury theorem’ of Nicolas de Condorcet, an 18th-century French philosopher who was one of the first to apply mathematics to the social sciences. Condorcet’s theory describes collective decisions, outlining how democratic decisions tend to outperform dictatorial ones. If, for example, each member of a jury has only partial information, the majority decision is more likely to be correct than a decision arrived at by a single juror. Moreover, the probability of a correct decision increases with the size of the jury. B Now it is becoming clear that group decisions are also extremely valuable for the success of social animals, such as ants, bees, birds, and dolphins. Bees make collective decisions, and they do it rather well, according to Christian List of the London School of Economics, who has studied group decision-making in humans and animals. Researchers led by Dr. List looked at colonies once the original colony reaches a certain size. The queen goes off with about two-thirds of the worker bees to live

This year, the number of retired pensioners in the UK exceeded the number of people under 18 for the first time in history. That’s remarkable in its own right, but the real “population explosion” has been among the oldest of the old — the centenarians. In fact, this group is the fastest-growing demographic in much of the developed world. In the UK, the number of centenarians has increased by 60 per cent since the early twentieth century, and their ranks are set to swell even further, thanks to the ageing baby-boomer generation: by 2030 there will be about a million worldwide. These trends raise social, ethical and economic dilemmas. Are medical advances artificially prolonging life, with little regard for the quality of that life? If growing numbers of elderly people become dependent on state or family support, society faces skyrocketing costs and commitments. Yet researchers who study the oldest old have made a surprising discovery that presents a less pessimistic view of the future than many anticipate. It is becoming clear that people who break through the 90-plus barrier represent a physical elite. Far from gaining a longer burden of disability, their extra years tend to be healthy ones. And