Evolution och biologi

Evolution, biologi och genetik

I denna meny kommer att läggas ut artiklar vilka nyanserar den gängse bilden av att det mesta här i livet är så kallade sociala konstruktioner. Snarare finns mycken forskning och rön som pekar på att evolutionära, genetiska och biologiska faktorer (i samspel med miljön) har en avgörande roll för mänskligt beteende. Detta kullkastar rådande jämlikhetsdoktriner vilka präglar den västerländska politiken. Att vi ska vara jämlika i avseende ha lika rättigheter och skyldigheter är bra för samhället. Däremot är det rentav skadligt att tro att vi alla är (jäm)lika i betydelsen har lika genetiska förutsättningar. Vi har olika förutsättningar som kompletterar varandra. Utan läkaren, snickaren, städaren eller (den naturvetenskapliga) forskaren fungerar inte samhället. Män och kvinnor har generellt sett olika genetiska förutsättningar, och även mellan etniska och rasliga grupper har forskningen funnit sådana skillnader bl a vad gäller sjukdomar och intelligens. Dessa skillnader påverkar våra kognitiva förmågor, hur vi tolkar och uppfattar världen, hur vi löser problem osv. Om 2000-talet kommer att bli det hereditära perspektivets århundrade återstår att se.

· Gunnar Adler-Karlsson: Jämlikhetens dödförklaring

. Charles Murray: IQ Will Put You In Your Place

. Philippe Ruhston: Review of IQ and the Wealth of Nations

Jämlikhetens dödförklaring
Det är förunderligt hur den sanning som varje häst- eller hunduppfödare känner till skall ha så svårt att slå igenom när det gäller oss människor. Dvs sanningen att en stor del av våra egenskaper och vårt beteende ligger i våra sen årtusenden nedärvda gener.

Ungefär så suckar Thomas J. Bouchard Jr, ihop med fyra medarbetare, när de lägger fram resultaten av drygt tio års studier av enäggstvillingar. Det sker i en artikel i Science den 12 oktober 1990. Dess titel är "Ursprunget till psykologiska skillnader mellan människor: Minnesota-studien av tvillingar som fostrats isär". Denna sammanfattning av över hundra olika forskningsresultat borde snarast översättas och bli obligatorisk läsning för alla politiker, lärare, samhällsdebattörer, jounalister och kulturskribenter. Ty den visar att dessa inte har någon betydelse, nja,, i alla händelser inte den stora betydelse som de själva gärna vill tro. Det är bara deras gener som betyder något.

Tvillingar eller i något enstaka fall trillingar, som skiljts åt i livets begynnelse är sällsynta. Tidigare finns bara tre ordentliga studier av dem. Nu redovisar Bouchard & Co resultaten av ungefär femtio timmars medicinska och psykologiska test på var och en individ i över hundra sådana par. Från dessa generaliserar de, troligtvis med rätta, till mänskligheten.

Enäggstvillingar är kopior av varandra. De föds med samma gener och samma arvsanlag. Växer de då upp på olika håll, i olika familjeförhållanden, kan man få en test på om det är arvet eller miljön som spelar störst roll för den vuxne individens personlighet. Om det är det genetiska arvet som är viktigt, bör likheterna vid vuxen ålder vara stora; om det är kultur och miljö, små.

Detta är inte bara en psykologisk testfråga utan en av de djupaste skiljelinjerna mellan en konservativ människosyn och en radikal. Styrs historien av en oföränderlig "mänsklig natur" eller kan vi, genom att med kulturella medel söka omskapa samhället, också förändra den mänskliga naturen? Ingalunda är frågan heller ny. "Många och hårda öden drabbade städerna under dessa inre slitningar, öden som förekommit och alltid skola förekomma så länge människonaturen är oföränderlig." Orden gäller inte Rumänien eller Etiopien i dag. De är Thukydides, vår förste moderne historieskrivare, och har 2400 år på nacken.

Vad som däremot är nytt är de starka beläggen för att den konservativa grundsynen är vetenskapligt mest välgrundad, oavsett hur de socialistiska delarna av våra själar må rysa. Bouchard & Co drar två huvudslutsater av sitt material: "(I) genetiska faktorer utövar en uttalad och genomträngande påverkan på beteendevariationer, och (II) effekten av att uppfostras i samma hem är, i fråga om psykologiska egenskaper, försumbar."

Som i drygt ett hundratal likartade, men mindre och metodiskt mindre väl genomförda, tidigare studier av intelligens, visar Minnesotaforskarna här att lite drygt två tredjedelar av skillnader i intelligens mellan individer är genetiskt nedärvd. Om du själv har adopterats bort till en kulturellt torftig mijö med usla skolor, och din enäggstvillingbror har fostrats hos en professorlig akademiledamot med tillgång till elitskolor, så är ni vid vuxen ålder ändå ungefär lika intellgenta som ni varit om ni gemensamt vuxit upp i endera miljön.

Bouchards siffror är aningen högre än i tidigare studier. Det förklaras med en skillnad i materialet. Tidigare studier har mest sysslat med barn och ungdom. Denna med vuxna individer. Och, visar det sig, det kulturella inflytandet under ungdomen minskar och arvet slår hårdare igenom ju äldre vi blir. Det är detta som kan förklara skillnaden mellan tidigare studier, som säger att femtio à sextio procent av våra intelligensskillnader är medfödda, och denna, som säger att sjuttio procent är det.

En lång rad andra psykologiska drag, ej bara när det gäller psykologisk kapacitet av olika slag utan också läggnings- och smakfrågor, har studerats på samma sätt, Nästan överallt, t o m när det gäller estetiska, religiösa och politiska attityder, finner man häpnadsväckande stora likheter mellan enäggstvillingar, intressant nog lika stora om de uppfostrats ihop eller isär! Detta ger ytterligare ett belägg för att det är generna som slår igenom.

Men miljön då, spelar den och kulturella faktorer ingen som helst roll? Jo, det gör den naturligvis, men slumpartat och osystematiskt. De likheter mellan enäggstvillingar som fostrats ihop, som miljön kan ha skapat, kan blott mätas till några få procent, inte ens till en tiondel av de genetiska effekterna. Miljöns effekter för att skapa våra personligheter tycks, i jämförelse med vårt genetiska arv, vara försumbara!

Polacken Kopernikus heliocentriska världsbild publicerades 1543, samma år han dog. Det var nog tur för honom, ty den inkvisition som hade den andliga makten i Polen lyckades i tvåhundra år i hans hemland förhindra varje allvarlig diskussion om det förhatliga faktum att solen inte snurrade runt Vatikanen. Bouchard är nog dömd att bli behandlad på ett likartat sätt av dagens massmediala inkvisition. Ty också hans resultat berövar människorna en del av den makt och det förnuft, som de älskar att tro sig utrustade med. Det är djuret i oss, icke något upphöjt kulturellt förnuft, som främst formar vår identitet!

Det finns redan en studie, M. Snyderman och S Rothmans The IQ Controversy, som klart dokumenterat att massmedia systematiskt har snedvridit vetenskapliga resultat, när det gäller arvets betydelse för intelligensen. Och en av Sveriges största kulturredaktioner1 är så avgrundsmässigt okunnig i desssa frågor, att den nyligen upphöjde Hans och Greta till Europas paradexempel på bouchardska enäggstvillingar. Vilket är absurt, då sådana givetvis måste vara av samma kön.

Varför är denna typ av kunskap så förhatlig för radikaler? Djupast sett, tror jag, därför att den slår mot deras grundtanke, den, att de är bättre och förnuftigare än dagens herrar, de förhatliga kapitalisterna. Deras tro, att bara de själva får makten skall allt bli bättre, blir genom denna forskning lika illa underbyggd, som tron på Godots återkomst. De tvingas inse att också de lider av en djuriskt nedärvd mänsklig natur, som under socialistiska fanfarer kan leda till stalinism. De nödgas förstå, att liberala maktfördelningsteorier är oändligt mycket mer välgrundade än varje form av proletariatets eller någon annans diktatur.

Det har en tid varit populärt att tillvita Alva och Gunnar Myrdal en diktatorisk vilja att manipulera fram en ny mänsklig natur i svenska folket under 30-talet. Dessa kritiker glömmer då att åtskilliga skolor under mellankrigstiden levde i nån form av optimistiskt rus om möjligheterna att med kulturella medel snabbbt förbättra människans natur. Prometeus andra gåva, den blinda förhoppningen, var gemensam för dem; blott medlen skilde ryska kommunister (revolution, äganderätten) från amerikanska socialingenjörer (tekniska framsteg) och svenska socialdemokrater (skola, välfärd).

Det är emellertid denna barnatro som övervintrande marxister liksom socialdemokrater, som ibland tycks tro att sanningen är vad man kommer fram till i MBL-förhandlingar, nu slutgiltigt måste uppge. Bouchard & Co:s väl genomförda forskning har förpassat sådan optimism till historiens avfallsberg.

Det finns åtskilliga andra konsekvenser, om man tar Bouchards sanningar på allvar. Bara två exempel.

För ett tag sen klagade en amerikansk Moskva-ambassadör över att det var farligt svårt att rekrytera intelligenta undgomar till UD. De gick alla till näringslivet. Om det nu är sant, att alla inte kan bli lika intelligeta oavsett vilken skolpolitik ett land bedriver, följer det att begåvningsgruppen är begränsad. Om då en viss del av samhället, t ex den med höga inkomster, lyckas locka till sig en stor andel av dessa högt begåvade individer, då ökar denna dels relativa makt. Om politiken, däremot, får ett så lågt anseende, att ingen intelligent ungdom vill ta i den, då kommer framtidens grundlagar att skrivas av och för ABB och Volvo. Hur går det då för demokratin?

Om begåvade kvinnor vill "förverkliga sig själva" och därför väljer karriären framför barnafödandet, kommer, relativt sett, antalet barn till dumma kvinnor att växa. Om då produktivitet, vilket några forskare visat, ökar med den genomsnittliga intelligenkvoten, kommer ett land, som i en generation pressar ut kvinnorna i karriären, att i nästa bli uppköpt av Japan, där kvinnorna är så intelligenta att de stannar hemma och föder intelligenta barn.

För min hälsas skull bör jag nog lägga till, att detta icke är min, och icke heller Bouchards tes. Den har framförts av en i dessa sammanhang extra förargelseväckande men dödsallvarlig professor, H J Eysenck.

Själv drar jag gärna två slutsatser och gör ett framtidsscenario av denna genetiska determinism.

Hatet förvandlas till tragik!

Det är min första slutsats. När vi människor, som vi gjort tvärs igenom historien, tror att världens många olyckor och lidanden förorsakas av våra fiender eller motståndare, och att de skulle försvinna om "vår" grupp finge makten, då hatar vi lätt våra onda fiender. Inser vi däremot att dessa olyckor måhända är följden av vår nedärvda allmänmänskliga natur, och skulle växa fram oavsett vilken grupp som sitter vid makten, då förvandlas vårt hat till en känsla av tragik inför människans villkor.

Vår kamp bör då mera riktas inåt än utåt!

Det är min andra slutsats. Den gäller nog individer såväl som partier, företag och nationer. Om det är generna som i stort styr vårt beteende och därmed våra samhällen, bör vår stora kamp inte handla om hur vi skall kunna slå ihjäl våra motståndare, utan hur vi gemensamt med dem skall kunna sublimera vår nedärvda aggressivitet för att behärska de onda drifterna i oss och befrämja de goda. Någon liten frihet har vi nämligen!

Där får såväl politiker som samhällsvetare ett projekt, som räcker för full sysselsättning de närmsta hundra åren!

Avslutningsvis ett litet scenario.

Genkonungen, Herren över den "genom"2 som människorna nu skall söka kartlägga, ler när han betraktar folks jämlikhetssprattel under ledare som Jesus, Franciskus, Lenin, Branting och Ingvar Carlsson. Han vet att hans gener till minst 99,9 procent var likadana för tvåtusen år sen och att de - oavsett all genmanipulation - till 99,9 procent kommer att vara likadana också år 4000 efter Kristus.

Människans natur kommer icke att ha förändrats.

Däremot kommer hennes verktyg att vara oändligt mycket mer raffinerade. Och han vet att hennes instrument återverkar, förvisso inte på hennes natur, men väl på hennes sociala beteende, så som atombomben skapat fred i Europa efter 1945. Det är därför fullt möjligt att hon år 4000 A D har lärt sig leva och samarbeta i en enda värld, långt fredligare och rikare än i dag, i vilken allas människovärde äntligen också blir respekterat. Detta har hon i så fall uppnått, inte trots utan tack vare ojämlikheten. Hon har nämligen lärt sig att nyttja denna på bästa sätt, till allas fördel. Det har hon lyckats med just därför att en viss ojämlikhet i makt och rikedom, liksom i intelligens och ledarförmåga, tas som fullkomligt självklara yttringar av den grundläggande, genetiskt nedärvda och därför ofrånkomliga ojämlikheten mellan människor.

Genkungen frågar sig, om människorna nu skall inse att Bouchard & Co måste anses ha gett dödsstöten åt realismen i alla drömmar om perfekt jämlikhet. Och han frågar sig, om de är mogna och har andlig styrka nog för att leva med denna insikt.
GUNNAR ADLER-KARLSSON

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1. Givetvis Dagens Nyheters under en redaktör vid namn Arne Ruth.
2. Svenska Dagbladets kulturredaktör strök i originalartikeln de två sista bokstäverna i detta ord, "genom", som så sent som 1991 inte ens var känt för Sveriges kulturredaktörer i sin biologiska betydelse, dvs som summan av DNA-innehållet i alla gener i vilken form av liv som helst. I februari 2001 publicerades människans genom, 2002 musens. Därvid fann man bl.a. att 99 procent av musens gener har samma funktion hos dem som hos oss. Mössen har dock ett halvdussin extra gener för att lukta sig fram till goda ostar, människan ett halvdussin extra gener för den intelligens, med vars hjälp vi kan tillverka extra goda ostar. I övrigt är det i stort sett samma sak! (GAK tillägg i jan. 2003)

IQ Will Put You In Your Place

Imagine several hundred families which face few of the usual problems that plague modern society. Unemployment is zero. Illegitimacy is zero. Divorce is rare and occurs only after the children's most formative years. Poverty is absent - indeed, none of the families is anywhere near the poverty level. Many are affluent and all have enough income to live in decent neighbourhoods with good schools and a low crime rate. If you have the good fortune to come from such a background, you will expect a bright future for your children. You will certainly have provided them with all the advantages society has to offer. But suppose we follow the children of these families into adulthood. How will they actually fare?

A few years ago the late Richard Herrnstein and I published a controversial book about IQ, The Bell Curve, in which we said that much would depend on IQ. On average, the bright children from such families will do well in life - and the dull children will do poorly. Unemployment, poverty and illegitimacy will be almost as great among the children from even these fortunate families as they are in society at large - not quite as great, because a positive family background does have some good effect, but almost, because IQ is such an important factor.

"Nonsense!" said the critics. "Have the good luck to be born to the privileged and the doors of life will open to you - including doors that will let you get a good score in an IQ test. Have the bad luck to be born to a single mother struggling on the dole and you will be held down in many ways - including your IQ test score." The Bell Curve's purported relationships between IQ and success are spurious, they insisted: nurture trumps nature; environment matters more than upbringing.

An arcane debate about statistical methods ensued. Then several American academics began using a powerful, simple way of testing who was right: instead of comparing individual children from different households, they compared sibling pairs with different IQs. How would brothers and sisters who were nurtured by the same parents, grew up in the same household and lived in the same neighbourhood, but had markedly different IQs, get on in life?

The research bears out what parents of children with unequal abilities already know - that try as they might to make Johnny as bright as Sarah, it is difficult, and even impossible, to close the gap between them.

A very large database in the United States contains information about several thousand sibling pairs who have been followed since 1979. To make the analysis as unambiguous as possible, I have limited my sample to brothers and sisters whose parents are in the top 75 per cent of American earners, with a family income in 1978 averaging £40,000 (in today's money).

Families living in poverty, or even close to it, have been excluded. The parents in my sample also stayed together for at least the first seven years of the younger sibling's life.

Each pair consists of one sibling with an IQ in the normal range of 90-110 ,a range that includes 50% of the population. I will call this group the normals. The second sibling in each pair had an IQ either higher than 110, putting him in the top quartile of intelligence (the bright) or lower than 90, putting him in the bottom quartile (the dull). These constraints produced a sample of 710 pairs.

How much difference did IQ make? Earned income is a good place to begin. In 1993, when we took our most recent look at them, members of the sample were aged 28-36. That year, the bright siblings earned almost double the average of the dull: £22,400 compared to £11,800. The normals were in the middle, averaging £16,800.

These differences are sizeable in themselves. They translate into even more drastic differences at the extremes. Suppose we take a salary of £50,000 or more as a sign that someone is an economic success. A bright sibling was six-and-a-half times more likely to have reached that level than one of the dull. Or we may turn to the other extreme, poverty: the dull sibling was five times more likely to fall below the American poverty line than one of the bright. Equality of opportunity did not result in anything like equality of outcome. Another poverty statistic should also give egalitarians food for thought: despite being blessed by an abundance of opportunity, 16.3% of the dull siblings were below the poverty line in 1993. This was slightly higher than America's national poverty rate of 15.1%.

Opportunity, clearly, isn't everything. In modern America, and also, I suspect, in modern Britain, it is better to be born smart and poor than rich and stupid. Another way of making this point is to look at education. It is often taken for granted that parents with money can make sure their children get a college education. The young people in our selected sample came from families that were overwhelmingly likely to support college enthusiastically and have the financial means to help. Yet while 56% of the bright obtained university degrees, this was achieved by only 21% of the normals and a minuscule 2% of the dulls. Parents will have been uniformly supportive, but children are not uniformly able.

The higher prevalence of college degrees partly explains why the bright siblings made so much more money, but education is only part of the story. Even when the analysis is restricted to siblings who left school without going to college, the brights ended up in the more lucrative occupations that do not require a degree, becoming technicians, skilled craftsmen, or starting their own small businesses. The dull siblings were concentrated in menial jobs.

The differences among the siblings go far beyond income. Marriage and children offer the most vivid example. Similar proportions of siblings married, whether normal, bright or dull - but the divorce rate was markedly higher among the dull than among the normal or bright, even after taking length of marriage into account. Demographers will find it gloomily interesting that the average age at which women had their first birth was almost four years younger for the dull siblings than for the bright ones, while the number of children born to dull women averaged 1.9, half a child more than for either the normal or the bright. Most striking of all were the different illegitimacy rates. Of all the first-born children of the normals, 21% were born out of wedlock , about a third lower than the figure for the United States as a whole, presumably reflecting the advantaged backgrounds from which the sibling sample was drawn. Their bright siblings were much lower still, with less than 10% of their babies born illegitimate. Meanwhile, 45% of the first-born of the dull siblings were born outside of marriage.

The inequalities among siblings that I have described are from 1993 and are going to become much wider in the years ahead. The income trajectory for low-skill occupations usually peaks in a worker's twenties or thirties. The income trajectory for managers and professionals usually peaks in their fifties. The snapshot I have given you was taken for an age group of 28-36 when many of the brights are still near the bottom of a steep rise into wealth and almost all the dulls' incomes are stagnant or even falling. . . .

The inequalities I have presented are the kind you are used to seeing in articles that compare inner-city children with suburban ones, black with white, children of single parents with those from intact families. Yet they refer to the children of a population more advantaged in jobs, income and marital stability than even the most starry-eyed social reformer can hope to achieve.

You may be wondering whether the race, age or education of siblings affects my figures. More extended analyses exist, but the short answer is that the phenomena I have described survive such questions. Siblings who differ in IQ also differ widely in important social outcomes, no matter how anyone tries to explain away the results. Ambitious parents may be dismayed by this conclusion, but it is none the less true for all that.

A final thought: I have outlined the inequalities that result from siblings with different IQs. Add in a few other personal qualities: industry, persistence, charm, and the differences among people will inevitably produce a society of high inequalities, no matter how level the playing field has been made. Indeed, the more level the playing field, and the less that accidents of birth enter into it, the more influence personal qualities will have. I make this point as an antidote to glib thinking on both sides of the Atlantic and from both sides of the political spectrum. Inequality is too often seen as something that results from defects in society that can be fixed by a more robust economy, more active social programmes, or better schools. It is just not so.

The effects of inequality cannot be significantly reduced, let alone quelled, unless the government embarks on a compulsory redistribution of wealth that raises taxes astronomically and strictly controls personal enterprise. Some will call this social justice. Others will call it tyranny. I side with the latter, but whichever position one takes, it is time to stop pretending that, without such massive compulsion, human beings in a fair and prosperous society will ever be much more equal than they are now.

CHARLES MURRAY (in the Sunday Times, UK, May 25 1997). A longer version of this article appears in the summer issue of The Public Interest.

Rewiev by Philippe Rushton: IQ and the Wealth of Nations, Richard Lynn and Tatu Vanhanen, Westport,
CT: Praeger (2002), 256 pp

The Bigger Bell Curve: Intelligence, National Achievement, and The Global Economy

This is a book that social scientists, policy experts, and global investment analysts cannot afford to ignore. It is one of the most brilliantly clarifying books this reviewer has ever read. IQ and the Wealth of Nations does for the study of human diversity and achievement among nations what The Bell Curve did for IQ and achievement in the USA. The central thesis is that the IQs of populations play a decisive role in the economic destinies of nations. With concise logic, Richard Lynn (professor emeritus of psychology at the University of Ulster in Northern Ireland), and Tatu Vanhanen (professor emeritus of political science at the University of Tampere in Finland), systematically document their stunningly straightforward and yet greatly overlooked hypothesis.

IQ and the Wealth of Nations analyses the relation between national IQ scores and measures of economic performance. In one analysis of 81 countries for which direct evidence on national IQs is available, mean national IQ correlates 0.71 with per capita Gross National Product (GNP) for 1998, and 0.76 with per capita Gross Domestic Product (GDP) for 1998. Other analyses consistently demonstrate national IQs predict both long term (1820-1922) and short term (1950-90; 1976-1998) economic growth rates measured variously by per capita GNP and GDP (mean rs ~ 0.60). Regression analyses of the 81 countries, and then of 185 countries, including 104 whose national IQs are estimated by averaging those from adjoining countries, shows the national differences in wealth are explained first, by the intelligence levels of the populations; second, by whether the countries have market or socialist economies; and finally, by unique circumstances such as, in the case of Qatar, by the possession of valuable natural resources like oil.

The book has a lucid, expository style. Chapter 1 reviews the various theories advanced over the last 250 years to explain why some countries are rich while others are poor. These include climate theories (temperate zones are said to be best), geographic theories (an East-West Axis is said to be best), modernization theories (urbanization and division of labor are said to be good), dependency theories (exploitation and peripheralization of poor nations are said to be bad), neoliberal theories (market economies are said to be good), and psychological theories (cultural values like thriftiness, the Protestant Ethic, and motivation for achievement are said to be good). While some of these theories almost certainly account for some of the disparities between countries, IQ scores turn out to be the single best predictor.

Chapters 2 to 4 discuss the nature of general intelligence, defined as a single unitary construct underlying performance on many specific cognitive tasks. A review of the literature shows that an individual's intelligence is an important determinant of his or her educational attainment, earnings, economic success, and other significant life outcomes. In the United States and Britain, the correlation between IQ and earnings is approximately 0.35, an association the authors argue is causal because: IQs predate earnings, are moderately heritable, are stable from 5 years of age onwards, and predict not only the earnings obtained in adulthood, but educational level and many other positive outcomes along the way. It makes sense that intelligence determines earnings because more intelligent people learn more quickly, solve problems more effectively, can be trained to acquire more complex skills, and work more productively and efficiently. Nations whose populations have high IQ levels also have high educational attainment and relatively large numbers of individuals who make significant contributions to national life, including the social infrastructure conducive to economic development. Conversely, nations with low levels of intelligence have low levels of educational attainment and relatively few individuals who make significant positive contributions to the social infrastructure. Low intelligence leads to a number of unfavorable social outcomes including crime, unemployment, welfare dependency, and single motherhood.

Chapter 5, the "Sociology of Intelligence," provides the first analyses of IQ at the group level, analyzing sub-divisions within nations such as those of cities, districts within cities, and regions. For example, studies carried out using the 310 administrative districts of New York City in the 1930s, found correlations of 0.40 to 0.70 between average IQ scores (gained from tests administered to children in schools) and measures of per capita income, educational attainment, welfare dependency, juvenile delinquency, mortality, and infant mortality. Similar studies carried out in regions of the British Isles, France, and Spain in the 1970s corroborate these relationships.

Chapters 6 to 8 (and their appendices) provide the critical core of the authors' analyses. These chapters describe in detail the variables and procedures by which the very testable hypotheses are tested and confirmed. The main IQ data are those published from 81 countries in the scientific literature over the previous 70 years. These are standardized to a British mean IQ of 100 with a standard deviation of 15, along with adjustments made for the secular increases in IQ which average 2.5 points a decade since the 1930s. The IQ data turn out to be highly reliable and valid. For example, in 45 countries for which there are two or more IQ measures, the inter-correlation is 0.94; in 38 countries for which there are data from international studies of achievement in mathematics and science, the correlation with IQ scores is 0.87.

The widespread though rarely stated assumption of economists and political scientists that the peoples of all nations have the same average level of intelligence turns out to be seriously incorrect. To the contrary, the evidence clearly reveals that there are considerable national differences in average intelligence level. The highest average IQs are found among the Oriental nations of North East Asia (IQ = 104), followed in descending order by the European nations of Europe (IQ = 98), the nations of North America and Australasia (IQ = 98), the nations of South and Southwest Asia from the Middle East through Turkey to India and Malaysia (IQ = 87), the nations of South East Asia and the Pacific Islands (IQ = 86), the nations of Latin America and the Caribbean (IQ = 85), and finally by the nations of Africa (IQ = 70).

One of the most surprising aspects of these data is how few nations have IQs as high as the British average of 100 (only 15 out of the 81, or less than 20%) and how many nations have IQs of 90 or less (40 out of the 81, almost 50%). The mean IQ of the 81 nations based on averaging the 7 regional IQs listed above is 90, a serious problem if the book's conclusion is correct that IQ = 90 is the threshold for having a technological economy. However, even if all the IQs turn out to be underestimates, it is likely that the rank-order among the nations will remain highly similar.

The range of IQs can be considerable within a geographic or political boundary. For example, in Latin America and the Caribbean, IQs range from 72 in Jamaica to 96 in Argentina and Uruguay and appear to be determined by the racial and ethnic make-up of the populations. Some racially mixed countries were assigned IQs proportionate to the IQs known for the various groups that make up the country. Thus, the national IQ for South Africa is given as 72 based on the weighted average for Whites, Blacks, Coloreds, and Indians (e.g., Owen, 1992).

For some (not all) analyses, 104 of the countries had their IQs estimated by averaging those from the most appropriate neighboring countries. For example, Afghanistan's IQ was estimated by averaging those from neighboring India (IQ = 81) and Iran (IQ = 84) to give an IQ of 83. The tables provided in IQ and the Wealth of Nations will be invaluable for researchers wishing to analyze subsets of the data or to extend them with additional data. Of course, the authors are aware that their data on both national IQs and economic indicators are only estimates and will contain errors. Their stunning results, however, leave little doubt that the margins of error were small enough to make the exercise meaningful. Error variance is typically randomly distributed and so works to diminish the strength of the associations between variables.

Although the correlations between IQs and economic performance are high, some countries had higher or lower per capita incomes than expected from their national IQs. These results are also informative. An analysis of those countries that deviate most from a regression line shows that a major additional factor for economic success consists of whether countries have market or socialist economies. A third contribution to wealth is the unique circumstances a country finds itself in.

Some of the countries with a large positive residual, and therefore a higher per capita income than would be predicted from their IQs, are Australia, Austria, Barbados, Belgium, Canada, Denmark, France, Ireland, Qatar, Singapore, South Africa, Switzerland, and the U.S. With the exception of Qatar, South Africa, and Barbados all of these are technologically highly developed market economies and their higher than predicted incomes could be attributed principally to this form of economic organization. Qatar's exceptionally high per capita income is principally due to its revenue from oil exporting, which is actually managed and controlled by corporations and people from European and North American countries. South Africa's much higher than expected per capita income derives from the high performance of the industries established and managed by the country's European minority. Similarly, Barbados's high positive residual can be traced to its well-established tourist industry and financial services, which are owned, controlled and managed by American and European countries.

Some of the countries with a large negative residual are Bulgaria, China, Hungary, Iraq, South Korea, the Philippines, Poland, Romania, Russia, Thailand, and Uruguay. Some of these are present or former socialist countries. Iraq has suffered from losing the Gulf War and a decade of UN trade sanctions. The Philippines have had a large amount of ethnic conflict, which other studies show results in decreased growth (across countries, a 1 SD increase in ethnic conflict is associated with a 0.30 SD decrease in growth rate; Easterly & Levine, 1997).

Chapter 9 contrasts IQ theory with its competitors, explains anomalies, and provides historical accounts of particular nations and regions. For example, two significant exceptions to the view that a tropical climate is detrimental to wealth are Singapore and Hong Kong, which lie in the tropical zone but are among the richest countries in the world. Two exceptions to the view that a temperate climate is beneficial are Lesotho and Swaziland, which lie slightly south of the Tropic of Capricorn, but are among the poorest countries in the world. The explanation for these differences can be understood in terms of intelligence theory: the people of Singapore and Hong Kong belong to the ethnic group with the highest IQs, while the people of Lesotho and Swaziland belong to the ethnic group with the lowest IQs. Historical vignettes are presented to explain how geographical isolation in central Asia (e.g., Tajikistan) may hinder economic development, and how economic fluctuations in Britain, Germany, and India have coincided with their governments' commitments to a market economy.

Modernization theories, according to which all nations would evolve from subsistence agriculture through to various stages of urbanization and industrialization, have worked for Western Europe and the Pacific Rim but have failed for the four remaining groups of nations (South Asia, the Pacific Islands, Latin America, and sub-Saharan Africa). IQ and the Wealth of Nations proposes that modernization theories worked for Western Europe and the Pacific Rim because these nations have appreciably the same or somewhat higher IQs than in the United States but they did not work for the other four groups of nations because these have lower IQs than those in the United States.

One of the most perplexing problems for the general theory is why the peoples of East Asia with their high IQs lagged behind the European peoples in economic growth and development until the second half of the 20th Century. China's science and technology were generally more advanced than Europe's for around two thousand years, from about 500 B.C. up to around 1500 A.D. In engineering, for example, China had canal systems, including canal locks, centuries ahead of Europe. In agricultural technology, the Chinese were the first to invent the collar and harness for horses (250 B.C.), and the chain pump for lifting water for irrigation (80 A.D.). They also invented the wheel barrow (240 B.C.), which did not appear in Europe until 1250 A.D. In printing and paper making, the Chinese invented making paper from bark (105 A.D.), printing from engraved wooden blocks (650 A.D.), printing with movable type (1040 A.D.), and color printing for paper money (1100 A.D.). In military technology, the Chinese invented the stirrup (475 A.D.) enabling soldiers on horseback to sit securely in the saddle and attack enemies with swords and lances, gunpowder (1044 A.D.), rockets (1200 A.D.), bombs producing shrapnel (1230 A.D.), small firearms shooting bullets from bamboo and metal tubes (1260 A.D.), and cannons (1280 A.D.). In Europe, gunpowder wasn't used until the 1300s. In marine technology, the Chinese built ships with rudders (2000 B.C.), and the magnetic compass for navigation at sea (1100 A.D.). Still other Chinese inventions included: cast iron (300 B.C.), iron chain supported suspension bridges (580 A.D.), spinning wheels (1035 A.D.), water powered mechanical clocks (1080 A.D.), and porcelain (840 A.D.). In mathematics, the Chinese invented the decimal point (1350 B.C.), and negative numbers (100 B.C.). In the 15th century Chinese inventiveness in science and technology came to an end and from that time on virtually all the important advances were made by Europeans, first in Europe and later in the U.S., perhaps because while Europeans developed the market economy, the Chinese stagnated through authoritarian bureaucracy and central planning.

The failure of Japan to develop economically until the late 19th century is largely attributed to a regulated economy and isolation from the rest of the world. By 1867-68 a revolution occurred and the new rulers embarked on a program to modernize Japan by adopting Western education and technology, and by freeing up the economy by transforming state monopolies into private corporations. Much of the Japanese economic success in the 20th century was built by adopting inventions made in the West, improving them, and selling them more competitively in world markets. Japan thereby built up its motorcycle, automobile, shipbuilding, and electronics industries. Although it is sometimes asserted that the Japanese have not made any significant scientific and technological innovations of their own, this underestimates their technological achievements. Philip's Science and Technology Encyclopedia (1998) lists a number of important discoveries and technological innovations made by the Japanese: the fiber-tipped pen (1960), "bullet" trains traveling at 210 km per hour, much faster than any Western trains (1964), laser radar (1966), quartz watches (1967), VHS video home systems (1976), flat screen televisions using liquid crystal display (1979), video discs (1980), CD-ROM (read only memory) disks (1985), digital audio tape (1987), and digital networks for sending signals along coaxial cables and optical fibers (1988).

African nations are at the other extreme to China and Japan in levels of national IQ and this may explain why they are such a major anomaly for modernization theory. The low rate of economic growth of African countries following their independence from colonial rule in the 1960s is one of the major problems in developmental economics. During the years 1976-98, the average rate of economic growth per capita GNP of the 41 nations of sub-Saharan Africa for which data are available is much lower than in the rest of the world. Many of the African countries even suffered negative per capita growth rate since 1960 (see also Easterly & Levine, 1997). Several economists have quantified all possible factors such as climate, ethnic diversity, geography, mismanagement, unemployment and the like and compared the situation to elsewhere in the world, especially Asia, and have concluded that these factors do not provide a complete explanation and that there is some "missing element." Some have identified the low level of "social capital," i.e., the widespread corruption and lack of trust in commercial relationships, poor roads and railways, unreliable telephones and electricity supplies, and the prevalence of tropical diseases such as malaria. IQ and the Wealth of Nations suggests that the missing link is IQ, and that some of the factors identified by economists as contributing to the low economic growth in sub-Saharan Africa are themselves attributable to a low level of intelligence in the populations. For example, the poor telephone services and electricity supplies, the low agricultural yields, and the poor advice given by government advisory boards are themselves due to the low average levels of IQ. With a cognitive capacity of IQ = 70, the populations of Africa cannot be expected to match the rates of economic growth achieved elsewhere in the world.

In chapter 10, the final chapter, various predictions are made. One clear prediction is that future growth is most likely in those countries with the largest negative residuals, that is, whose national IQ scores are high but whose present economic performance is weak. The countries of the former Communist Blocs -- such as Russia, Poland, Bulgaria, and Romania, and the People's Republic of China, and Vietnam -- are obvious possibilities. This chapter also lists some of the factors (both environmental and genetic) that might raise IQ scores, and so alleviate the problem. These include better nutrition, education, and health, and also ending the dysgenic fertility wherein the lowest IQ people produce the most children. For example, fertility figures from countries such as Brazil, the Dominican Republic, and Nicaragua show that among parents with secondary education in the late 1990s, the average number of children produced lies between 1.8 and 2.2, while among women with the least education, it lies between 5.0 and 6.1. Thus the least educated are having two to three times the number of children of the most educated. Since educational levels in these countries are to some degree correlated with intelligence, their demographic trend is strongly dysgenic.

The final conclusion of IQ and the Wealth of Nations is that national differences in IQ are here to stay, as is the gap between rich and poor nations. Hitherto, theories of economic development have been based on the presumption that the gaps between rich and poor countries are only temporary, and that they are due to various environmental conditions that could be changed by aid from rich countries to poor countries, and by poor countries adopting appropriate institutions and policies. It has been assumed that all human populations have equal mental abilities to adopt modern technologies and to achieve equal levels of economic development. The authors call for the recognition of the existence of the evolved diversity of human populations.
J. PHILIPPE RUSHTON
Department of Psychology, Uiversity of Western Ontario, Canada (in press, 22 October 2001, in Elsevier Science journal)

References
Easterly, W. & Levine, R. (1997). Africa's growth tragedy: policies and ethnic divisions. Quarterly Journal of Economics, 112, 1203-1250.
Owen, K. (1992). The suitability of Raven's Standard Progressive Matrices for various groups in South Africa. Personality and Individual Differences, 13, 149-159.
Philip's Science and Technology Encyclopedia (1998). London: Philip.