Two people from distinct populations spot each other from afar. Both have more incentives to avoid each other than to meet, so they turn around. Because it's stressful and/or people are disappointed that they didn't do what they were supposed to do, some barely remarkable differences get exaggerated to rationalize their emotions.
50,000 years later, the gene pool has been mixed rather well and any remaining differences are skin-deep at most. But now the "other" also gets closer, possibly in some proportion that is constant across time, and homo sapiens sapiens, the thinking thinking man, thinks thinks those brown eyes look really frighting.
50,000 years later, the gene pool has been mixed rather well and any remaining differences are skin-deep at most. But now the "other" also gets closer, possibly in some proportion that is constant across time, and homo sapiens sapiens, the thinking thinking man, thinks thinks those brown eyes look really frighting.
homo homini lupus est (quom qualis sit non novit)