Also a very famous painter during that time was Jackson Pollock. He was a very abstract painter. He used splashes and dropping to paint his paints, there wasn't any brush strokes. Insted of having a easel he put his canvas on the floor. Also he added foreign objects to his paintings like sand and broken glass.
Here is a example of a Pollock Painting:
"Shimmering Substance"
Robert Motherwell was also another abstract painter during the 1940's. He mostly experimented with different types of art, he was a active writer and reviewer of art of writings on art work. He also studied philosophy as Standford.
Here is a example of one of Motherwell's paintings:
"Elegy To The Spanish Republic"