In conclusion, this essay has discussed the general role of the nature-nurture debate and how it can affect the human traits and behavior. Clearly it can be seen that both genetic factors and the environment can influence the intelligence in human through the studies of twins and adoptees.
Another form of study in support of the nature-nurture debate is the study of adoptees. Research made has conclude that between the biological parents and adoptive parents, the adoptee is more similar to his or her biological parents (Sodorow, 1995). Adoption studies have found evidence that adopted children who share genes with their biological parents are greatly influence by genetic on their IQs (G pg 318). Similar studies have also found that adoptees share the same religious value as their biological parents rather than adoptive parents (Sodorow, 1995).
During the 15 years that I spent researching and writing my recently completed trilogy on racial and cultural issues, I was struck again and again with how common huge disparities in income and wealth have been for centuries, in countries around the world-- and yet how each country regards its own particular disparities as unusual, if not unique. Some of these disparities have been among racial or ethnic groups, some among nations, and some among regions, continents, or whole civilizations.
In the nineteenth century, real per capita income in the Balkans was about one-third that in Britain. That dwarfs intergroup disparities that many in the United States today regard as not merely strange but sinister. Singapore has a median per capita income that is literally hundreds of times greater than that in Burma.
During the rioting in Indonesia last year, much of it directed against the ethnic Chinese in that country, some commentators found it strange that the Chinese minority, which is just 5 percent of the Indonesian population, owned an estimated four-fifths of the capital in the country. But it is not strange. Such disparities have long been common in other countries in Southeast Asia, where Chinese immigrants typically entered poor and then prospered, creating whole industries in the process. People from India did the same in much of East Africa and in Fiji.
Occupations have been similarly unequal.
In the early 1920s, Jews were just 6 percent of the population of Hungary and 11 percent of the population of Poland, but they were more than half of all the physicians in both countries, as well as being vastly over-represented in commerce and other fields. In the early twentieth century, all of the firms in all of the industries producing the following products in Brazil's state of Rio Grande do Sul were owned by people of German ancestry: trunks, stoves, paper, hats, neckties, leather, soap, glass, watches, beer, confections and carriages.
In the middle of the nineteenth century, just three countries produced most of the manufactured goods in the world-- Britain, Germany, and the United States. By the late twentieth century, it was estimated that 17 percent of the people in the world produce four-fifths of the total output on the planet.
Such examples could be multiplied longer than you would have the patience to listen.
Why are there such disparities? In some cases, we can trace the reasons, but in other cases we cannot. A more fundamental question, however, is: Why should anyone have ever expected equality in the first place?
Let us assume, for the sake of argument, that not only every racial or ethnic group, but even every single individual in the entire world, has identical genetic potential. If it is possible to be even more extreme, let us assume that we all behave like saints toward one another. Would that produce equality of results?
Of course not. Real income consists of output and output depends on inputs. These inputs are almost never equal-- or even close to being equal.
During the decade of the 1960s, for example, the Chinese minority in Malaysia earned more than a hundred times as many engineering degrees as the Malay majority. Halfway around the world at the same time, the majority of the population of Nigeria, living in its northern provinces, were just 9 percent of the students attending that country's University of Ibadan and just 2 percent of the much larger number of Nigerian students studying abroad in foreign institutions of higher learning. In the Austrian Empire in 1900, the illiteracy rate among Polish adults was 40 percent and among Serbo-Croatians 75 percent-- but only 6 percent among the Germans.
Given similar educational disparities among other groups in other countries-- disparities in both the quantity and quality of education, as well as in fields of specialization-- why should anyone expect equal outcomes in incomes or occupations?
Educational differences are just one source of economic disparities. Even at the level of craft skills, groups have differed enormously, as they have in urbanization. During the Middle Ages, and in some places long beyond, most of the population of the cities in Slavic Eastern Europe were not Slavs. Germans, Jews, and other non-Slavic peoples were the majority populations in these cities for centuries, while the Slavs were predominantly peasants in the surrounding countrysides. Prior to the year 1312, the official records of the city of Cracow were kept in German-- and the transition that year was to Latin. Only decades later did Poles become a majority of the population of Cracow. Only over a period of centuries did the other cities of Slavic Eastern Europe acquire predominantly Slavic populations. As late as 1918, 97 percent of the people living in the cities of Byelorussia were not Byelorussians.
Until this long transition to urban living took place among the Slavs, how could the wide range of skills typically found in cities be expected to exist in populations that lived overwhelmingly in the countryside? Not only did they not have such skills in Eastern Europe, they did not have them when they immigrated to the United States, to Australia, or to other countries, where they typically worked in low-level occupations and earned correspondingly low incomes. In the early years of the twentieth century, for example, immigrants to the United States from Eastern and Southern Europe earned just 15 percent of the income of immigrants from Norway, Holland, Sweden, and Britain.
Groups also differ demographically. It is not uncommon to find some groups with median ages a decade younger than the median ages of other groups, and differences of two decades are not unknown. During the era of the Soviet Union, for example, Central Asians had far more children than Russians or the peoples of the Baltic republics, and so had much younger median ages. At one time, the median age of Jews in the United States was 20 years older than the median age of Puerto Ricans. If Jews and Puerto Ricans had been absolutely identical in every other respect, including their cultures and histories, they would still not have been equally represented in jobs requiring long years of experience, or in retirement homes, or in activities associated with youth, such as sports or crime.
Nothing so intractably conflicts with our desires for equality as geography. The physical settings in which races, nations, and civilizations have evolved have had major impacts on the cultures developed within those settings. Those settings vary enormously-- as do their cultural consequences. How could Scandinavians or Polynesians know as much about camels as the Bedouins of the Sahara? And how could the Bedouins know as much about fishing as the Scandinavians or Polynesians? The peoples of the Himalayas have certainly not had an equal opportunity to acquire seafaring skills. Nor have Eskimos had an equal opportunity to acquire knowledge and experience in growing pineapples or other tropical crops. Ability in the abstract is one thing, but specific capabilities of doing specific things is what matters economically.
Too often the influence of geography on wealth is thought of narrowly, in terms of natural resources that directly translate into wealth, such as oil in the Middle East or gold in South Africa. But, important as such differences in natural wealth are, geography influences even more profound cultural differences among the people themselves.
Where geography isolates people, whether in mountain valleys or on small islands scattered across a vast sea, there the cultural exposures of those people to the outside world are very limited and so, typically, is their technological advancement. While the rest of the world exchanges goods, knowledge, and innovations from a vast cultural universe, isolated peoples have been largely limited to what they alone have been able to develop.
Few, if any, of the great advances in human civilization have come from isolated peoples. As the eminent French historian Fernand Braudel put it, the mountains almost always lag behind the plains-- even if the races in the two places are the same. Potatoes and the English language both reached the Scottish lowlands before they reached the highlands. Islam reached North Africa's Rif mountains long after the people in the plains had become Moslems.
When the Spaniards invaded the Canary Islands in the fifteenth century, they found people of a Caucasian race living at a stone-age level. So were the Australian aborigines when the British discovered them in the eighteenth century. Geographically imposed cultural isolation takes many forms and exists in many degrees. Cities have long been in the vanguard of human progress, all over the world, but cities do not arise randomly in all geographic settings. Most of the great cities of the world have developed on navigable waterways-- rivers or harbors-- but such waterways are by no means equally or randomly distributed around the world. They are very common in Western Europe and very rare in sub-Saharan Africa. Urbanization has long been correspondingly common in Western Europe and correspondingly rare in sub-Saharan Africa. One-third of the land mass of Europe consists of islands and peninsulas but only one percent of the land mass of South America consists of islands and peninsulas.
Navigable waterways have been economically crucial, especially during thousands of years of human history before the development of railroads, trucks, and airplanes. Before the transcontinental railroad was built, it was both faster and cheaper to reach San Francisco from a port in China than from Saint Louis. People in the city of Tbilisi bought their kerosene from Texas-- 8,000 miles away across water -- rather than from the Baku oil fields, less than 400 miles away across land.
Such vast differences in costs between water transport and land transport affect what can be transported and how far. Gold or diamonds can repay the costs of transport across thousands of miles of land, but grain or coal cannot. More important, the size of a people's cultural universe depends on how far they can reach out to other peoples and other cultures. No great civilization has developed in isolation. Geography in general and navigable waterways in particular set the limits of a people's cultural universe, broadly or narrowly. But these limits are by no means set equally for all peoples or all civilization.
For example, when the British first crossed the Atlantic and confronted the Iroquois on the eastern seaboard of what is today the United States, they were able to steer across the ocean in the first place because they used rudders invented in China, they could navigate on the open seas with the help of trigonometry invented in Egypt, their calculations were done with numbers invented in India, and their general knowledge was preserved in letters invented by the Romans. But the Iroquois could not draw upon the knowledge of the Aztecs or the Incas, whose very existence they had no way of knowing. The clash was not between the culture created by the British versus the culture created by the Iroquois. It was a clash between cultural developments drawn from vast regions of the world versus cultural developments from a much more circumscribed area. The cultural opportunities were unequal and the outcomes were unequal. Geography has never been egalitarian.
A network of rivers in Western Europe flow gently through vast plains, connecting wide areas economically and culturally. The rivers of tropical Africa plunge a thousand feet or more on their way to the sea, with cascades and waterfalls making them navigable only for stretches between these natural barriers-- and the coastal plain in Africa averages just 20 miles. Regular rainfall and melting snows keep the rivers of Western Europe flowing throughout the year but African rivers have neither-- and so rise and fall dramatically with the seasons, further limiting their usefulness. The two continents are at least as dramatically different when it comes to natural harbors. Although Africa is more than twice the size of Europe, it has a shorter coastline. That is because the European coastline continually twists and turns, creating innumerable harbors, while the African coastline is smooth, with few harbors. How surprising is it that international commerce has played a much smaller role in the economic history of Africa than in that of Europe in general and Western Europe in particular?
These particular geographic disparities are by no means exhaustive. But they are suggestive of some of the many ways in which physical settings have expanded or constricted the size of the cultural universe available to different peoples. One revealing indication of cultural fragmentation is that African peoples are 10 percent of the world's population but have one-third of the world's languages.
In controversies over "nature versus nurture" as causes of economic and other disparities among peoples and civilizations, nature is often narrowly conceived as genetic differences. Yet geography is also nature-- and its patterns are far more consistent with history than are genetic theories. China, for example, was for many centuries the leading nation in the world-- technologically, organizationally, and in many other ways. Yet, in more recent centuries, China has been overtaken and far surpassed by Europe. Yet neither region of the world has changed genetically to any extent that would account for this dramatic change in their relative positions. This historic turnaround also shows that geographic limitations do not mean geographic determinism, for the geography of the two regions likewise underwent no such changes as could account for the reversal of their respective positions in the world.
Back in the fifteenth century, China sent ships on a voyage of exploration longer than that of Columbus, more than half a century before Columbus, and in ships more advanced than those in Europe at the time. Yet the Chinese rulers made a decision to discontinue such voyages and in fact to reduce China's contacts with the outside world. European rulers made the opposite decision and established world-wide empires, ultimately to the detriment of China. In short, geography sets limits but people determine what they will do within those limits. In some parts of the world, geographic limits have been set so narrowly that the peoples of these regions have never had the options available to either the Europeans or the Chinese. Isolation has left such regions not only lagging economically but fragmented culturally and politically, making them prey to larger, more prosperous, and more powerful nations.
We have seen how cultural handicaps have followed Eastern Europeans as they immigrated overseas, leading to lower levels of income than among immigrants from Western Europe who settled in the same places, whether North America or Australia. If Africans had immigrated voluntarily to the Western Hemisphere, instead of in bondage, is there any reason to believe that their earnings would have achieved an equality that the Slavic immigrants failed to achieve?
There is no question that Africans and their descendants faced the additional barrier of color prejudice, but can we measure its effects by assuming that black people would have had the same income and wealth as white people in the absence of this factor-- especially in view of the large disparities among different groups of white immigrants, not to mention the rise of some non-white groups such as Chinese Americans and Japanese Americans to incomes above the national average?
Put differently, geography has not only cheated many peoples of equal cultural opportunities, it has also cheated all of us today of a simple criterion for measuring the economic and social effects of other variables, such as prejudice and discrimination.
Nothing has been more common in human history than discrimination against different groups, whether different by race, religion, caste or in innumerable other ways. Moreover, this discrimination has itself been unequal-- more fierce against some groups than others and more pervasive at some periods of history than in others. If there were not so many other powerful factors creating disparities in income and wealth, it might be possible to measure the degree of discrimination by the degree of differences in economic outcomes. Even so, the temptation to do so is seductive, especially as a means of reducing the complexities of life to the simplicities of politics. But the facts will not fit that vision.
Anyone familiar with the history of race relations in the Western Hemisphere would find it virtually impossible to deny that blacks in the United States have faced more hostility and discrimination than blacks in Latin America. As just one example, 161 blacks were lynched in one year in the United States, but racial lynching was unknown south of the Rio Grande. Perhaps the strongest case against the predominance of discrimination as an explanation of economic disparities would be a comparison of blacks in Haiti with blacks in the United States. Since Haiti became independent two centuries ago, Haitian blacks should be the most prosperous blacks in the hemisphere and American blacks the poorest, if discrimination is the overwhelming factor, but in fact the direct opposite is the case. It is Haitians who are the poorest and American blacks who are the most prosperous in the hemisphere-- and in the world.
None of this should be surprising. The fact that discrimination deserves moral condemnation does not automatically make it causally crucial. Whether it is or is not in a given time and place is an empirical question, not a foregone conclusion. A confusion of morality with causation may be politically convenient but that does not make the two things one.
We rightly condemn a history of gross racial discrimination in American education, for example, but when we make that the causal explanation of educational differences, we go beyond what the facts will support. Everyone is aware of times and places when the amount of money spent educating a black child was a fraction of what was spent educating a white child, when the two groups were educated in separate systems, hermetically sealed off from one another, and when worn-out textbooks from the white schools were then sent over to the black schools to be used, while new and more up-to-date textbooks were bought for the white children. The number of days in a school year sometimes differed so much that a black child with 9 years of schooling would have been in class the same number of days as a white child with only 6 years of schooling. It seems so obvious that such things would account for disparities in test scores, for example.
But is it true?
There are other groups to whom none of these factors apply-- and who still have had test score differences as great as those between black and white children in the Jim Crow South. Japanese and Mexican immigrants began arriving in California at about the same time and initially worked in very similar occupations as agricultural laborers. Yet a study of a school district in which their children attended the same schools and sat side-by-side in the same classrooms found IQ differences as great as those between blacks and whites attending schools on opposite sides of town in the Jim Crow South. International studies have found different groups of illiterates-- people with no educational differences because they had no education-- with mental test differences larger than those between blacks and whites in the United States.
What is "the" reason? There may not be any such thing as "the" reason. There are so many cultural, social, economic, and other factors interacting that there was never any reason to expect equal results in the first place. That is why plausible simplicities must be subjected to factual scrutiny.
Back in 1899, when the schools of Washington, D.C. were racially segregated and discrimination was rampant, there were four academic high schools in the city-- three white and one black. When standardized tests were given that year, the black academic high school scored higher than two of the three white academic high schools. Today, exactly a century later, even setting such a goal would be considered hopelessly utopian. Nor was this a fluke. That same high school was scoring at or above the national average on IQ tests during the 1930s and 1940s. Yet its physical plant was inadequate and its average class size was higher than that in the city's white high schools.
Today, that same school has a much better physical plant and per-pupil expenditures in the District of Columbia are among the highest in the nation. But the students' test scores are among the lowest. Nor was this school unique in having had higher academic achievements during a period when it seemingly lacked the prerequisites of achievement and yet fell far behind in a later period when these supposed prerequisites were more plentiful.
This is obviously not an argument for segregation and discrimination, nor does it deny that counter-examples might be found of schools that languished in the first period and did better in the second. The point here is much more specific-- that resources have had little or nothing to do with educational quality. Numerous studies of schools in general have shown that, both within the United States and in international comparisons. It should be no surprise that the same applies to black schools.
Politically, however, the disbursement of resources is by no means inconsequential. The ability to dispense largess from the public treasury has for centuries been one of the signs and prerogatives of power in countries around the world. In electoral politics, it is vital as an element in re-election. But the ultimate question is: Does it in fact make people better off? How that question is answered is much less important than that it be asked-- that we not succumb to social dogmas, even when they are intellectually fashionable and politically convenient.
It is also important that economic and other disparities be confronted, not evaded. Best-selling author Shelby Steele says that whites in America today are fearful of being considered racists, while blacks are fearful of being considered inferior. Social dogmas may be accepted because they relieve both groups of their fears, even if these dogmas neither explain the past nor prepare for the future.
It should be axiomatic that there is not unlimited time, unlimited resources, or unlimited good will among peoples-- anywhere in the world. If we are serious about wanting to enlarge opportunities and advance those who are less fortunate, then we cannot fritter away the limited means at our disposal in quixotic quests. We must decide whether our top priority is to smite the wicked or to advance the less fortunate, whether we are looking for visions and rhetoric that make us feel good for the moment or whether we are seeking methods with a proven track record of success in advancing whole peoples from poverty to prosperity.
In an era when esoteric theories can be readily turned into hard cash from the public treasury, our criteria must be higher than what can get government grants for middle-class professionals. It must instead be what will rescue that youngster imprisoned, not only in poverty, but also in a social and cultural isolation that has doomed whole peoples for centuries in countries around the world. When we promote cultural provincialism under glittering labels, we must confront the hard question whether we are throwing him a lifeline or an anchor.
History, geography, and cultures are influences but they are not predestination. Not only individuals but whole peoples have moved from the backwaters of the world to the forefront of civilization. The late Italian author Luigi Barzini asked of Britain: "How, in the first place, did a peripheral island rise from primitive squalor to world domination?" The story of Japan's rise from a backward country in the mid-nineteenth century to one of today's leading economic powers has been at least equally as dramatic. Scotland was for centuries known for its illiteracy, poverty, and lack of elementary cleanliness. Yet, from the mid-eighteenth to the mid-nineteenth century, most of the leading intellectual pioneers of Britain were Scots, and Scots also become prominent in business, banking, medicine, and engineering-- not only in Britain but around the world.
These and other dramatic and heartening rises of whole peoples came from doing things that were often directly the opposite of what is being urged upon less fortunate groups in the United States today. Far from painting themselves into their own little cultural corner and celebrating their "identity," these peoples sought the knowledge and insights of other peoples more advanced than themselves in particular skills, technologies, or organizational experience. It took centuries for the English to absorb the cultural advances brought by such conquerors as the Romans and the Normans and by such immigrants as the Huguenots, Germans, Jews, and others who played a major role in developing the British economy. Their early dependence on outsiders was painfully demonstrated when the Romans pulled out of Britain in the fifth century, in order to go defend their threatened empire on the continent, and the British economy and political structure both collapsed. Yet ultimately-- more than a thousand years later-- the British rose to lead the world into the industrial revolution and controlled an empire containing one-fourth of the land area of the earth and one-fourth of the human race.
Japan's economic rise began from a stage of technological backwardness that was demonstrated when Commodore Perry presented them with a gift of a train. Here was their reaction:
The history of nature-nurture debate started off with famous philosophers like John Locke and Jean Jacques Rousseau (Feldman, 1997). John Locke believed that human behavior is solely influenced by nurture. By this is meant that human were born with an empty brain and we learnt and developed through the experiences in life (Myers, 2000). In contrast, Jean Jacques Rousseau suggested that human development was due to individual’s genetic factors which means that human trait and behavior is more or less develop the moment of birth (Feldman, 1997). In the present time, psychologists share the same thinking that both nature and nurture interdependently rely on each other in human development (Westen, 2002). Clearly it can be seen that the concept of the debate had changed. Now, psychologists are more interested in to what extend can genetic factors and the environment, affect the development of human trait and behavior (Feldman, 1997).
Every person in this world has their own distinctive personality and behavior. People may wonder why an individual may act the way they do. Thus psychologists had put this into a study of whether an individual’s behaviors are caused by hereditary or the environment. This study is known as the nature-nurture debate. This essay will discuss the nature-nurture debate in relation to how it influences the human traits and behavior focusing on twin and adoption studies. Furthermore the essay will also discuss how hereditary and the environment influences on the behavior of intelligence base on twin and adoption studies.
Cultural trends now fashionable in the West favour an egalitarian approach to life. People like to think of human beings as the output of a perfectly engineered mass production machine. Geneticists and sociologists especially go out of their way to prove, with an impressive apparatus of scientific data and formulations that all men are naturally equal and if some are more equal than others, this is attributable to nurture and not to nature. I take an exception to this general view. It is my firm conviction, supported by years of observation and experimentation, that men are not equal, that some are stupid and others are not, and that the difference is determined by nature and not by cultural forces or factors. One is stupid in the same way one is red-haired; one belongs to the stupid set as one belongs to a blood group. A stupid man is born a stupid man by an act of Providence. Although convinced that fraction of human beings are stupid and that they are so because of genetic traits, I am not a reactionary trying to reintroduce surreptitiously class or race discrimination. I firmly believe that stupidity is an indiscriminate privilege of all human groups and is uniformly distributed according to a constant proportion. This fact is scientifically expressed by the Second Basic Law which states that