In course of explaining (rightly in the main) that the humanitarian case for stopping the people-smuggling trade is 'disingenuous hooey', Lionel Shriver refers to the 2019 paper in Nature outlining the psychological difference between (small-c) 'conservatives' who focus moral obligation on local ties, and (small-l) 'liberals' who pledge allegiance to universalist abstractions. Unfortunately, we are not normally willing to acknowledge that human psychology - not least this feature of it - is a disaster area.
In respect of migration in particular, neither conservative nor liberal psychology is capable of relating to the international geopolitics which any nation - even the USA - cannot avoid. The new polarisation into rival power blocs challenges the West (including Britain) to deal with the causes of migration - not least why those migrants who would prefer to stay home feel unable to do so - so as to limit the opportunities for China and Russia to expand their influence in Asia, Africa, and Latin America. Again, the environmental campaigners rarely point out - really they should be shouting - that if we fail to deal effectively with climate change there will be far more migrnants than there are now. Moreover, those would be likely to be more desperate and ruthless.
The inability of conservative and liberal psychologies to address concerns at once hard practical and universal is a key factor in the inability of governments to form coherent migration policies or even to explain them properly. At the same time, psychology is ready to produce Darwinian explanations of how human psychology evolved for the distant past without indicating how it might need to adapt once again for the conditions of the present. The fact that we ourselves are responsible for the change of environment since the Stone Age is beside the point. No matter what the reasons for changes in a species' environment, Nature has the same short way with those that fail to adapt. 'Conservative' and 'liberal' psychologies are singularly maladapted for the high-tec, global trade, mass or total destruction weapons environment of today where hard Realpolitik and universalism run together. The basic principle of evolution has not changed in 4 billion years: Adapt or die.