Kohn et al. (1983)have been researching the impact of work on personalities of the worker using longitudinal data and comparing the personalities of the workers ten years apart. Those working in jobs free from close supervision where complex operations and independent judgement demonstrated a lasting impact on their personalities. They became self confident and showed greater flexibility in handling ideas. Those in more routine jobs had lower levels of self confidence,were more fatalistic, more likely to experience psychological distress, and were less flexible in dealing with ideas.