How far back in time do you recognise yourself? There may be long self-life and short self-life people; speculatively, the difference may even be genetic.
Some interesting videos here on the question of selves and persons (two words often used by different people to indicate different distinctions, so you can have a long talk at cross-purposes all too easily).
Too much content for me to summarise quickly, but I was particularly struck by Galen Strawson’s view of self-life (as it were). Human beings may live three score and ten years, but the unchanged self really only lasts a short while. Rigorously speaking he thinks it might only last a fraction of a second, but he believes that there are, as it were, different personality types here; people who have either a long or a short sense of identity over time. He is apparently near one end of the spectrum, not really identifying with the Galen Strawson who was here only half an hour ago. Myself, I think I’m towards the other end. When I look at photographs of my five-year-old self, I feel it’s me. There are many differences, of course, but I remember with special empathy what it was like to look out through those eyes.
Strawson thinks this is a genuine difference, not yet sufficiently studied by psychology; perhaps it even has a genetic basis. But he thinks short self-life and long self-life people can get along perfectly well; in fact the combination may make a strong partnership.
One other interesting point, Raymond Tallis thinks personhood is strongly social. On a desert island your personhood would gradually attenuate until you became more or less ‘Humean’ and absorbed in your environment and daily island tasks. It doesn’t sound altogether bad…