One thing to note is that the last ice age finished about 12k years ago, and human reoccupation of very large tracts of asia, north america and europe could not

One thing to note is that the last ice age finished about 12k years ago, and human reoccupation of very large tracts of asia, north america and europe could not have been over night. Large areas (for example the UK north of London) were under ice sheets, but much larger areas would have been tundra and frozen dessert [1] Additionally there would have been huge inundation of the coastal areas that were previously human occupied. The creation of new opportunities and the chaos of the disruption of old settled communities may simply have meant that there was a multi-generational selection for successful adventurous cowards! [1] https://en.wikipedia.org/wiki/Last_Glacial_Maximum#/media/File:Last_glacial_vegetation_map.png https://en.wikipedia.org/wiki/Last_Glacial_Maximum#/media/Fi...