Knowing some of these people immigrant and US born poor the answer is quite obvious to me. No study needs to be conducted, only casual observation. Here are the key differences.
The influence of the US culture is obvious in the US born American. He expects more for less effort (entitlement), he is more easily discouraged when facing adversity, he expects someone to care for him and hand him all the tools and opportunity, his expectations are polar opposite of the immigrant (who expects nothing but what he has earned with his bare hands). He is disillusioned easily and when discouraged, drinks or abuses drugs to forget his problems. He supports liberal or socialist ideals because he feels that they will put cash into his pocket and bring down the wealthy people who "oppress" him. The US born minority (non white) thinks the cards are stacked against him, the minority immigrant sees other minority immigrants who have created wealth and aspires to replicate their success despite it's challenges.
The culture of the US born poor person comes from the media (not just news - all media) they consume and the media saturated people surrounding them. Plain and simple that is the most corrosive thing. Secondarily, the idea that these people must be helped out, they don't have to fight through adversity to succeed. This is the worst thing you can do to a man. A man must be a man and have a fighting will to survive and flourish. If you make him a dependent, you are extinguishing this flame... perhaps forever.
Some of the immigrants I know come from socialist countries and they are coming partly to escape from them. They respect the opportunity to work hard and succeed whereas the US born man does not. Americans have been given too much, they watch too many TV shows and other media which slants their view of reality and what life really is like. They have been over medicated and indoctrinated with views that are unproven and those which claim they are proven "cannot be replicated" (psychological studies).
America needs to look back to see what has worked for us when we were great, take some good things we have now that have worked and put some other things back to the way they once were.
The most revealing thing when looking at immigrants is how by the third generation, they hardly stick out from the lazy culture that their grandparents were so different from.
TLDR: America is too liberal, has too much cheap crap from China (materialism) and watches too much Garbage TV and other media and is too medicated. We are lazy. An immigrant of any color comes over here and works his ass off, escaping poverty.