Mason is a researcher in the area of robotic manipulation, and is the author of two highly cited textbooks in the field.
[1][2] In 2004, Mason received widespread media attention for developing the first origami folding robot, demonstrating advances in difficult manipulation tasks.
Horn, and his Ph.D. thesis Manipulator Grasping and Pushing Operations was advised by Tomas Lozano-Perez and Berthold K.P.
He worked at the IBM Thomas J. Watson Research Center as a research visitor in 1978, and has been teaching at the School of Computer Science and the Robotics Institute at Carnegie Mellon University since 1982.
He is currently a member of the editorial and advisory board for the International Journal of Robotics Research.