Many safety professionals, especially those with a background in engineering, view psychology as a subjective "touchy-feely" discipline. When I hear this I'm quick to defend the science of psychology. I assert that psychological principles are founded on objective empirical research, and not on common sense.
So along with the science of engineering and medicine, we have the science of human behavior. Just as we have engineering and medical technology to benefit our quality of life, we also have behavioral technology to improve human performance.