As physical differences such as skin colour, teeth and eye shape are clearly genetic in origin researchers such as Lynn and Vanhanen (2002) believe the same can be said of intelligence. They provide, as part of the support for this belief, adoption studies with black children adopted by white, middle class couples. The fact that the adoptive parents are middle class is supposed to infer that the child has the very best environment available to encourage IQ gains. This study did reveal black children’s scores were well below their white counterparts. It would seem this example suggests not only an inherited level of intelligence but also a race effect.
Alternatively the discrepancy in scores may be caused by poor nutrition in the womb. Studies of low birth weight infants add some weight to this belief. Aylward, Pfeiffer, Wright, & Verhulsts (1989) revealed that those children who were classified as low birth weight had reduced IQ scores by around 6 points. Equally, it appears that early childhood is crucial in determining IQ. Preschool children in two Guatemalan villages were given protein supplements (Pollitt, Gorman, Engle, Martorell & Rivers, 1993). Ten years later these same children were found to have significantly greater scores on achievement tests than their peers.
Yet another influence affecting a child’s intelligence level may be the stress the mother was under when pregnant. Stress is known to cause various health and cognitive problems in susceptible individuals (Bartlett, 1998). It is not straining the boundaries of credibility to hypothesise that maternal stress levels may negatively affect the unborn child’s intelligence levels, perhaps in tandem with poor nutrition. A study by Huttunen and Niskanen (1978), investigating stress on woman pregnant when widowed gives support to this idea. They found that the children, born to widowed mothers, had more psychiatric disorders than those children who lost their fathers after birth. This points to other potential contributors to cerebral functioning.
Twin studies are also frequently offered as evidence for a genetic influence in intelligence. Monozygotic (white) twins separated at birth have been found to have similar IQs suggesting a genetic link (Loehlin, Lindzey & Spuhler, 1975). However it must be noted that Sir Cyril Burt (1972), who is accused of scientific fraud, produced the data for a large proportion of twin studies. Nevertheless even if these figures are accepted, they are misleading. The results cannot be used in generalising to populations, as the small sample is unrepresentative of the whole population i.e. mostly white and middle class participants. Despite this criticism, Neisser et al (1996) believe that the statistics suggest that the white divide with African- Americans is a myth because the results show more similarities than differences. Anyway is it right to generalise to populations on the basis of an inferred genetic status of intelligence within certain individuals?
That is not to imply there is no inherited genetic potential of intelligence. Jensen thought intelligence was genetically fixed and claimed 80% on its heritability. He would have trouble explaining how crystallised intelligence expands throughout the lifespan (Flynn, 1987). In reality the nature nurture components in intelligence are impossible to separate and quantify (Neisser et al, 1996) so no percentages should be placed on the genetic or environmental contributions. The focus should not be whether intelligence is inherited but whether within group differences of IQ can be used to conclude differences between-groups.
Richards (1997) used height to illustrate. Height is highly inherited; small parents will normally have small children. However if we attribute the means of one population to another and claim the differences are attributed to genetics we could be misinterpreting the data. This is because other factors affect height, including nutrition, and these may be seriously affecting the mean of the population. Similarly differences between ‘ racial’ groups intelligences could be attributed to other factors. Drawing conclusions from comparisons of mean scores therefore could be erroneous.
Kempthorne (1990) a quantitative geneticist advised that as most literature on species heritability cannot be experimentally influenced then results should be ignored. Subsequently, research that seeks to find correlations through adoption studies and other data that cannot be directly manipulated should not be taken into account when evaluating either individual or group differences. Does that mean all intelligence research is invalid? Not necessarily as critics do not deny the stability or predictability of tests when it comes to academic performance (Neisser et al, 1996).
When Rushton used racial comparisons he applied sociobiological and individual differences approaches in tandem (see Zuckerman, 1988). The first stresses genetic equivalence within species and species differences while the second is interested in variety within species. Racial comparisons fit in between the two approaches but make a point of setting wide homogeny in behaviour within races. Moreover when studying individual differences there are comparisons with groups but never on the grounds of their physical differences only their traits. Rushton however classed races on strictly physical differences. He placed people into three groupings, Caucasian, Negroid or Mongoloid. In his analysis of 25 countries on Barratt and Eysenck’s EPQ (1984) he grouped Nigeria and Uganda as Negroid even though their scale pattern on the EPQ was grossly dissimilar. Rushton even grouped Pygmies with Watusi but failed to provide a rational for doing so (see Yee, Fairchild, Weizmann & Wyatt, 1993).
Since the 1930s the concept of race as a category has been discarded. The Psychological Abstracts of 1990, 1991(see Yee at al, 1993) reveals psychologists still group race and ethnicity together even though one stems from nature and the other nurture. In putting them together psychology has obscured their real meanings (Yee et al, 1993). Psychology has allowed societies political, cultural and social norms to seriously affected its scientific position. So how then do other disciplines define races?
Biologists identify race as an inbreeding group that is geographically secluded and that has obvious physical differences. However, this definition could fit the inbreeding Amish in America who maintain isolation through culture and religion (Zuckerman, 1988). Anthropologists consider race as a recent variation caused by changes in climate and concentrated gene pool maintained through geographic segregation. On the other hand racial groupings have traditionally been made through categorising physical features. Skin colour, eye colour and shape, nose shapes and head shape and size were (and still are for some) all common classification criterion. Nevertheless these groupings would not be in agreement with the anthropological definition. Skin colour varies with some Caucasians having darker skins than some Negroes (Barnicott, 1964). Blood groups, A, B & O are found across the traditional race categories. Different blood types do not correspond to race categories, for example Africans and Oceanic Negroes have similar physical characteristics but do not share blood types (Zuckerman, 1990). Richards (1997) believes there are no groups large enough today (in America at least) that would fit the criteria for race. Additionally recent revelations have sealed the lid on the old concept of race.
The Human Genome Project sequencing the three billion human genomes (complete set of DNA) has found no evidence for the differentiating of Homo sapiens on account of race (Human Genome Project, 2003). In fact we share 99.9% of our nucleotide bases. “The human genome is our shared inheritance," said , the head of the Human Genome Project (Olson, 2001, online). Venter, whose company has been sequencing and analysing human DNA, adds "Race has no genetic or scientific basis," (Olson, 2001, online) It is astounding that psychology, a scientific discipline, could base its theories on an inaccurate concept of biological group differences and be allowed to do so for so long after it has been officially discredited. Still the question remains what accounts for the differences in intelligence scores?
One explanation could be that IQ tests do not measure complete intelligence. Neisser et al (1996) believe that IQ tests are a good indicator of general intelligence. Nevertheless they also state that standardised tests do not include all forms of intelligence e.g. wisdom or common sense. Flynn (1987) believes tests merely correlate, albeit poorly with intelligence. The author proposes because tests do not measure all our components of intelligence any conclusions from scores should be tentative. Accordingly as the debate is based on ‘ race’ score disparities the argument is defective, as disparity of a few variables ought not to be extended to claims of total intelligence quotients, in this instance in ‘races’. However there are psychologists who still believe that race is still a legitimate classification and investigative subject. Brand (1997) published his theories advocating the inferiority of blacks on measures of ‘g’. Some however are not so open about their investigative variables as Scarr notes (1988) there is a tendency to investigate race issues indirectly, by deception, by not including them in the research design. At the present time despite the official line that race is discredited as a variable for research (Billig, 1998) it appears Scarr’s observation highlights otherwise.
Flynn (1987) provides another indirect explanation to intelligence score differences. He identified a rising trend in mean IQ test scores by 15 points (equal to one standard deviation), commonly called the Flynn effect. It is interesting to note the Ravens Progressive Matrices Test (tests fluid intelligence and reasoning) which is designed to be culture free is the purest determinant of the problem solving abilities that are most affected by culture. Flynn (1987) when addressing the issue of what has caused IQ gains determined that culture distance separates generations. Until the causes of these differences between generations are identified then the cultural variants that are important are unknown. This means that between groups cultural distance cannot be proved to be dissimilar. Subsequently IQ differences cannot be used to identify between groups differences.
The ideological definition of racism is attributing characteristics to a group according to race and implying that these characteristics are socially contemptible (Cardwell, 1996). When asking whether race and IQ is justifiable in psychology the consequences of research conclusions should be a vital factor. Research into this area only serves racially motivated individuals who may be in a position to implement policies that can harm others. Zuckerman (1990) advises on setting a standard for race investigations. However as the Human Genome Project has shown there is no genetic basis for race. It is nearly 74 years since race has been discredited as a research variable but it seems it is a hard variable to discard.
IQ test scores do not reveal environmental factors in intelligence levels; they give us a score based on the mean of a population. How can the average of a particular group of individuals be expanded to an entire population? Even culturally defined ethnic groupings should not be used, as there is a risk of harm stemming from policies based on research findings. Everyone therefore should be taken on his or her own merit.
In answer to the question of whether race and intelligence research is a justifiable area of research in psychology the answer is definitely not. The author would argue that although we are all free agents we should not be allowed to perform research that causes potential harm to others, especially as standards of race are unrealistic and intelligence tests are measuring a manufactured concept that centres on only limited components of aptitude. Since we are all the same species and race is a false concept the race debate should be settled. Even if we substitute race with ethnic groupings we still cannot generalise to populations since complex interactions determine differences in IQ.
As, on the whole, Western society regards the race theme for research as entirely discredited (Yee at al, 1993). Since that is the situation psychologists such as Brand should be prevented from expounding their views to the general public in order to prevent the promotion of racist stereotypes i.e. blacks are born stupid. Intelligence researchers need to identify all types of intelligences and try to form a test as culture free as possible. However the impact any research findings will have on the political and social climate should be vital when generating theories based on apparent patterns of scores.
True objectivity is a rarity, perhaps even a fantasy, so given that the world (outside the discipline) is affected by and influences psychologists’ theories then the discipline should be held morally accountable if research encourages others to vilify and persecute their fellowman. It is our morality that distinguishes us from lower primates and it should not be discarded in the drive for objectivity. Finally, the percentage of nature versus nurture in intelligence is elusive. Therefore it is suggested psychologists forget about trying to separate genetic and environmental contributions to intelligence because both are really one entity.
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