I think Lighter is right about evolutionary thinking and his argument about the ballad not necessarily being older because 'simpler' very interesting.

But Lighter is also right to suggest that views about what is 'simple' and what is 'complex' might quickly get complicated.

For me, one basic tenet of Roud's book is that what music and song ordinary people of middling and lower 'ranks' or 'classes' enjoyed, played and sang in past times is interesting in itself. He provides masses of interesting information, based on contemporary written accounts.