Historians are always aware that human events don't swivel on a dime every time the decades change.
And by the way, I am one with the math experts who insist a decade should be marked in the same way we normally count numbers, (1,2,3) , that is 1951-1961 rather than 1950-1960 for the Fifties.
Fat chance we'll ever be taken seriously though.
But we also have the historians' concept of the Long Forties, the Long Sixties etc.
So I offer up 1953 to 1963 as one way to see the Long Fifties, from the easing of tension after Stalin's death until the later easing of tension after the Atomic Testing Ban was approved. The two events being a good way to bookmark both ends of the Long Fifties....