As the name suggests, we do know that Alden Dow once used this as his bedroom. If you take a look in the built-in cabinet, you will see books in which we have found Alden's name and in the drawers you will see items like a razor and bowties, which belonged to him.
Since this bedroom was built in 1914, it reflects a new decorative style. By this time the craftsman style of architecture and home decor had become popular, so we see these elements in the simple lines of the trim around the doors, the built-in cabinet, and even the bathroom fixtures.