 These three men also recognized Sigmund Freud's understanding of anxiety as a "signal of danger" and that some things in Freud's work could be altered to fix this.Miller, Dollard and Mowrer believed that a person who was relieved of high anxiety levels would experience what is called "anxiety relief".Together with fellow psychologist O. Hobart Mowrer, Miller gives his name to the "Miller-Mowrer Shuttlebox" apparatus.