The First Men and the Last Men

In the comments below there is a discussion about whether personhood is a continuous or categorical trait. I lean toward the former proposition as a matter of fact, but let's entertain the second. What if personhood, and in particular consciousness and moral agency, emerged repeatedly over the past two million years in singular individuals? A model I propose is that the reason that 'behavioral modernity' exhibited such a long lag behind 'anatomical modernity' is that the first conscious human kept killing themselves. After all, imagine that you come to awareness and all your peers are...well, 'dirty apes.' You are literally the sane man in the asylum. This is similar the idea proposed, reasonably enough, that a demographic 'critical mass' was required for cultural evolution to truly enter into 'lift-off.' In any case, perhaps ~50,000 year ago a psychopath was born who could live with the knowledge that their days were ...