The ever-cumulating dispersion, not only of information, but also of population, across the globe, is the great social phenomenon of this age. Regrettably, cultures are being homogenized, but cultural differences are also being demystified, and intermarriage is escalating, across ethnic groups within states and between ethnicities across the world. The effects are potentially beneficial for the improvement of cognitive skills, from two perspectives. We can call these "the expanding in-group" and the "hybrid vigor" effects.
The in-group versus out-group double standard, which had and has such catastrophic consequences, could in theory be eliminated if everyone alive were to be considered to be in everyone else's in-group. This Utopian prospect is remote, but an expansion of the conceptual in-group would expand the range of friendly, supportive and altruistic behavior. This effect may already be in evidence in the increase in charitable activities in support of foreign populations that are confronted by natural disasters. Donors identifying to a greater extent with recipients make this possible. The rise in frequency of international adoptions also indicates that the barriers set up by discriminatory and nationalistic prejudice are becoming porous.
The other potential benefit is genetic. The phenomenon of hybrid vigor in offspring, which is also called heterozygote advantage, derives from a cross between dissimilar parents. It is well established experimentally, and the benefits of mingling disparate gene pools are seen not only in improved physical but also in improved mental development. Intermarriage therefore promises cognitive benefits. Indeed, it may already have contributed to the Flynn effect, the well known worldwide rise in average measured intelligence, by as much as three I.Q. points per decade, over successive decades since the early twentieth century.
Every major change is liable to unintended consequences. These can be beneficial, detrimental or both. The social and cognitive benefits of the intermingling of people and populations are no exception, and there is no knowing whether the benefits are counterweighed or even outweighed by as yet unknown drawbacks. Nonetheless, unintended though they might be, the social benefits of the overall greater probability of in-group status, and the cognitive benefits of increasing frequency of intermarriage entailed by globalization may already be making themselves felt.