I recall reading something about the Scotch-Irish. BTW, it must be Scottish because many Trinidadians of Scotch and partial Scotch descent have a bit of the same culture. The Irish would come pretty close too.
I've been to Trinidad, and I was struck by that same similarity that you mentioned. It was a bit muddied, as I was there with a church group, and we were interfacing with hindus primarily, and some muslims, so my cultural perceptions were more framed within the paradigm of God, but I did notice it nonetheless.
It's funny you say that, I live in Dorchester, MA which is what many people consider "South Boston" even though it is a seperate part of the city.
Dorchester is probably one of the most Irish neighborhoods in the country - though it is pretty diverse, pretty much every white person here identifies themself as Irish (even if they aren't).
Currently, there are thousands of Irish immigrants in this part of the city, most of them are illegals who plan on staying only a few years. Most of them are poorly or moderately educated farm boys from tiny towns in Dingle, Kerry or Donegal.
Anyway, there is definitely a subtle backlash against the Irish Guys in my neighborhood. They are all nice guys, for the most part, but they do carry on like 16 year olds when a good number of them are over 30.
I've heard them referred to as Green N****rs by people who would never use that word to insult a black person, and who have parents or grandparents who come from the old sod themselves.
It exemplifies how there is a lot more than race behind people's prejudices.
Sowell's hair sure has gotten grey.