Maybe acquiring a necessity is less rewarding than acquiring something pursued for fun? The point I was trying to make is that a dollar is not a neutral reward,

Maybe acquiring a necessity is less rewarding than acquiring something pursued for fun? The point I was trying to make is that a dollar is not a neutral reward, and may cause a different response, that might otherwise be the same in all groups for something as neutral as "points". That the response to rewards differs between poor and rich in general does't seem to be testable using a reward that both groups perceive differently.