Not only plants and animals but also humans evolve in peculiar ways on an oceanic island. It is also true that some animals, birds and insects who come to such an island and some humans are peculiar even before they arrive.
It is said that it is a very adventurous elephant who will swim four miles from the mainland to a continental or channel island.
A human who turns his back on a continent to come to a distant island is equally adventurous. Even the older folks who come to retire are not the average retiree. And I'm not referring only to their financial station. To leave family behind, numerous cultural activities, people with similar backgrounds and interests, to come to a tropical island is a great adventure.
The Hawaiian Islands, of course, are American. They provide all the comforts of the Mainland. All the same foods, television shows, stores and movies. Coming here is not like moving to some outer island in some distant archipelago where one must depend upon native people for aid, comfort and education.
This being the case, people do not undergo great change in coming here. They might eat a little differently. They might dress a little differently. They might exercise more. They might feel healthier. But they do not undergo a powerful change in consciousness. They neither adapt nor adopt. Rather they change what is here into what it was they left.