It is possible to summarize our survey under the following four headings:

1. Members of different ethnic groups may react differently to comparable natural (usually complex) situations.

2. Laboratory measurements of various sensory functions of ethnic groups have often been contradictory; and even though some peripheral differences in perception are a priori probable, others may still be caused by cultural differences in cognition, memory content or motivation; these cognitive and memory differences may be best interpreted as differences in individually acquired but group characteristic reafference systems.

Factor analytic studies in Africa are compared with other cross-cultural investigations into the structure of abilities in different ethnic groups. Similarities and differences are noted; and environmental influences on the acquisition of skills are also summarized. A correlational study of wrong answers to a battery of thirty marker tests given to a group of predominantly Mashona students indicates that efficiency skills of numerical facility and memory remain at the first order of factor extraction, reasoning abilities emerge in second-order analysis, while perceptual styles are present in the third-order level. This study is used to hypothesize, in thecontext of African systems of thought, the existence of a primary thought mode that asserts itself in conditions involving repeated errors.

The session closed with the showing of extracts from films taken at the Olympic Games in Berlin in 1936. The focus in these extracts was on the differing abilities of various racial types, including a number of shots, many of them in slow motion, of the finals competitors in the high jump, the winning jump being of 6 ft 10½ in. Professor Kalmus was invited to make some comments on the Olympics and the athletes who compete in them.

Two different projections of world population for the years 1980 and 2000, viz. the United Nations Medium Variant Projection and Current Fertility Projection, are considered. Both show large increases in world population. When the more developed regions and the less developed regions are considered separately, the major part of the growth is seen to be concentrated in the less developed regions.

The changes in total population expected in the next 40 years (1960–2000) are seen to be very different from changes which have taken place in the last 40 years.

The age structure of the immigrant female population as shown by the 1961 Census was heavily biased towards the young adult age groups, where fertility rates are highest. The birth rate for such a population could be expected considerably to exceed the average for this country as a whole, due to differences in age structure alone. The Census also showed marked differences betwen the fertility rates of different groups of immigrants but suggested that for the most important groups —from the Irish Republic, the Indian sub-continent and the Caribbean—they then amounted to a completed family size of roughly ½ child above the England and Wales average. There were also marked differences in 1961 between the socio-economic structure of immigrant groups; such evidence as there is points to socio-economic factors as playing an important part in explaining the fertility of immigrants, and its possible change over time.

Until very recently physical anthropology has been more or less exclusively concerned with the study of the evolutionary origins of man and with race. During the first half of this century a vast body of literature accumulated describing the physical characteristics of the world's many populations, both past and present, and classifying these populations into races. Innumerable classifications appeared, which not only varied according to their authors' views as to which race a particular population should be ascribed but also, very strikingly, in the number of races that were considered as compounding the human species. Some recognized as few as three or four, others as many as thirty or more. No small effort was spent in searching for methods to ascribe individuals to one race or another and some people were regarded as being more ‘typical’ of a particular race than others.

I was thinking as we went through the first three sessions of this symposium of a difficulty faced by human geneticists which is not faced by those who are concerned with the genetics of plants and animals, and which I do not think has been mentioned—though, certainly, it was implied in Dr Harrison's Galton Lecture.

The geneticist of plants and animals, if he is concerned with wild plants and wild animals, is considering their viability in a particular environment. The geneticist who is concerned with domestic strains is concerned with something which he knows much more precisely. He knows what he wants; he knows that he wants a cow that will give more milk, or a hen that will give more eggs.

When the United Nations Organization was set up in 1945, one of its first intellectual tasks was to define the problem of racism which had been one of the major factors in Hitler's rise to power and the subsequent devastation of Europe. Hence UNESCO asked a group of biologists and social scientists to draw up a statement in 1949. The original statement and a further version in 1951 proved, however, to be ambiguous and unsatisfactory in certain respects and the Director-General of UNESCO therefore called upon biologists to meet separately in Moscow in 1964 and for their meeting to be followed by a meeting of biologists, social scientists and lawyers which would then address itself to the specific sociological problem of racism.