1、That boys and girlsand men and womenare programmed by evolution to behave differently from one another is now widely accepted. Surely, no one today would think of doing what John Money, of Johns Hopkins University, did in 1967: amputating the genitalia of a boy who had suffered a botched circumcisio
2、n, and advising the parents to bring him up as a girl. The experiment didnt work, and the consequences were tragic. But which of the differences between the sexes are “biological”, in the sense that they have been honed by evolution, and which are “cultural” or “environmental” and might more easily
3、be altered by changed circumstances, is still fiercely debated.The sensitivity of the question was shown last year by a furore at Harvard University. Larry Summers, then Harvards president, caused a storm when he suggested that innate ability could be an important reason why there were so few women
4、in the top positions in mathematics, engineering and the physical sciences.Even as a proposition for discussion, this is unacceptable to some. But biological explanations of human behaviour are making a comeback as the generation of academics that feared them as a covert way of justifying eugenics,
5、or of thwarting Marxist utopianism, is retiring. The success of neo-Darwinism has provided an intellectual underpinning for discussion about why some differences between the sexes might be innate. And new scanning techniques have enabled researchers to examine the brains interior while it is working
6、, showing that male and female brains do, at one level, operate differently. The results, however, do not always support past clichs about what the differences in question actually are.Differences in behaviour between the sexes must, in some way, be reflections of systematic differences between the
7、brains of males and females. Such differences certainly exist, but drawing inferences from them is not as easy as it may appear.For a start, mens brains are about 9% larger than those of women. That used to be cited as evidence of mens supposedly greater intelligence. Actually, the difference is lar
8、gely （and probably completely） explained by the fact that men are bigger than women. In recent years, more detailed examination has refined the picture. Female brains have a higher percentage of grey matter （the manifestation, en bloc, of the central bodies of nerve cells）, and thus a lower percenta
9、ge of white matter （the manifestation of the long, thin filaments that connect nerve cells together）, than male brains. That, plus the fact that in some regions of the female brain, nerve cells are packed more densely than in men, means that the number of nerve cells in male and female brains maybe
10、similar.Oddly, though, the main connection between the two hemispheres of the brain, which is known as the corpus callosum and is made of white matter, is proportionately smaller in men than women. This may explain why men use only one side of the brain to process some problems for which women emplo
11、y both sides.These differences in structure and wiring do not appear to have any influence on intelligence as measured by IQ tests. It does, however, seem that the sexes carry out these tests in different ways. In one example, where men and women perform equally well in a test that asks them to work
12、 out whether nonsense words rhyme, brain scanning shows that women use areas on both the right and the left sides of the brain to accomplish the task. Men, by contrast, use only areas on the left side. There is also a correlation between mathematical reasoning and temporal-lobe activity in menbut no
13、ne in women. More generally, men seem to rely more on their grey matter for their IQ, whereas women rely more on their white matter.American exceptionalismThe worlds biggest insurance market is too splinteredKANSAS CITY, Missouri, is known more for its historical role as a cattle town than as a fina
14、ncial hub. But it is to this midwestern city, Americas 26th largest, that regulators and insurance executives from around the globe head when they want to make sense of the worlds largestand one of its weirdestinsurance markets.For it is in Kansas City that the National Association of Insurance Comm
15、issioners （NAIC） is housed. It oversees a market accounting for one-third of premiums written worldwide. Outside Kansas City, the market becomes a regulatory free-for-all. Each of Americas 50 states, plus the District of Colombia, governs its insurance industry in its own way.In an increasingly glob
16、al insurance market, Americas state-based system is coming under strong pressure to reform. Insurance has changed dramatically since the NAIC was set up in 1871, with growing sophistication in underwriting and risk management. Premiums in America have ballooned to $1.1 trillion and market power is i
17、ncreasingly concentrated in the hands of big players （some of them foreign-owned） that are pushing for an overhaul of the state-based system. “Its an extremely expensive and Byzantine process,” says Bob Hartwig, an economist with the Insurance Information Institute, a research group.Though a fiercel
18、y political issue, congressional support for simplifying the system is gaining ground. Both houses of Congress are looking at proposals to change the state-based system. Big insurers favour a version that would implement an optional federal charter allowing them to bypass the state-bystate regulator
19、y process if they choose. A similar system already exists for banks.Proponents of the changes see more efficiency, an ability to roll out products more quickly nationally and, ultimately, better offerings for consumers as a result. Yet some consumer groups favour state-based regulation. They believe
20、 it keeps premiums lower than they otherwise would be. Premiums as a percentage of gross output are lower in America than in several other countries.The political headwinds are strong: insurance commissioners are elected officials in some states （California, for instance） and appointed by the govern
21、or in others. The industry is also split: most of the countrys 4,500 insurers are small, and many of them have close ties with state-based regulators, whose survival they support. But even these forces may eventually be overcome.Elsewhere in the industry in America, there are other calls for reform.
22、 In a backdoor form of protectionism, American reinsurance firms have long benefited from a regulation that requires foreign reinsurers writing cross-border business into America to post more collateral than they do. “If you operate outside the borders of the US, they dont trust you one inch,” lamen
23、ts Julian James, head of international business at Lloyds of London, which writes 38% of its business in America.The collateral requirement was established because of worries about regulatory standards abroad, and the financial strength of global reinsurers. Today regulatory standards have been tigh
24、tened in many foreign markets. A majority of Americas reinsurance cover now comes from firms based abroad, including many that have set up offshore in Bermuda （for tax reasons） primarily to serve America.Too hot to handleDells battery recall reveals the technology industrys vulnerabilitiesTHERE is t
25、he nail test, in which a team of engineers drives a large metal nail through a battery cell to see if it explodes. In another trial, laboratory technicians bake the batteries in an oven to simulate the effects of a digital device left in a closed car on a sweltering dayto check the reaction of the c
26、hemicals inside. On production runs, random batches of batteries are tested for temperature, efficiency, energy density and output.But the rigorous processes that go into making sophisticated, rechargeable batteriesthe heart of billions of electronic gadgets around the worldwere not enough. On Augus
27、t 14th Dell, a computer company, said it would replace 4.1m lithium-ion batteries made by Sony, a consumer-electronics firm, in laptop computers sold between 2004 and last month. A handful of customers had reported the batteries overheating, catching fire and even explodingincluding one celebrated c
28、ase at a conference this year inJapan, which was captured on film and passed around the internet. The cost to the two companies is expected to be between $200m and $400m.In some ways, Dell is a victim of its success. The company was a pioneer in turning the personal computer into a commodity, which
29、meant squeezing suppliers to the last penny, using economies of scale by placing huge orders, and running efficient supply chains with little room for error. It all created a volatile environment in which mistakes can have grave effects.Since lithium-ion batteries were introduced in 1991, their capa
30、city to overheat and burst into flame has been well known. Indeed, in 2004 America banned them as cargo on passenger planes, as a fire hazard. But the latest problems seem to have arisen because of the manufacturing process, which demands perfection. “If there is even a nano-sized particle of dust, a small metal shard or water condensation that gets into the battery cell, it can overheat and explode,” says Sara Bradford of Frost & Sullivan, a consultancy. As the energy needs of devices have grown rapidly, so have the demands on batteries.The computing industrys culture is also partly to blam
