Following the Second World War and the world's experience of Nazism, assertions that ability was determined by inherited factors, or at least by factors that differed between races, were not generally accepted. But assertions that differences were caused by genetic factors did not disappear. These assertions were put forward in milder forms and then debated. In the 1970s there was a "sociobiology debate" ◆1. Research seeking to explain crime through genetic factors, while criticized, was nonetheless carried out◆2.