It's a combination of
an urban bass-thumping attitude
a bohemian lyrical approach
a slightly snoddy appreciation of melody and arrangement.
Each component is represented in every album. Kinda like Prince, Jamiroquai, Terence Trent D'Arby and Sting jamming impromptu. With Marvin Gaye and Johnny Guitar Watson egging them on.
Check out some song clips just to see what we're talking about.