He wasnt advancing this as proof that violent crime is decreasing: the evidence for that is in the statistics, which have been studied in great detail by a lot of people, all of whom have reached the same conclusion, that violent crime has been falling for as far back as detailed records go, with a year on year fall in recent decades. The only people who disagree with this are the campaigners for draconian crimimal laws (such as the expansion of the death penalty), who have an obvious reason to want to claim that crime is rising not falling.
What he was discussing was the secondary but important question of why, if this is so, popular belief says the exact opposite - that violent crime is more prevalent than ever. And I agree that the main reason is media focus. Another reason is contrast. If your everyday life is a jungle of threats and minor tussles, the occasional killing is just the way it goes. If normality is peace and safety, a murder in the next street makes you feel the world is falling apart.When I lived in Chapeltown in Leeds, which a few years before had been a crime jungle, a man who had lived there all his life told me firmly that what had changed it was jobs. The young men who used to hang out on the corners looking for a fight were working and bringing in a wage, and ready to call the cops if they thought someone was going to upset their new quiet life.
I think you need some sort of change in society for crime to decrease. Maybe better economical circumstances and jobs are in plenty?To a certain extent, all these things have happened. But one thing the original lecturer touched on, but which I think he underestimated, was the increase in life expectancy. "Expectancy" is an important word. In ages when a man in his '50s knew that he was living on borrowed time, that most of his contemporaries were dead of disease or violence and the Reaper would catch up with him soon, he had little motive to work for a better future. These days, a man of that age can realistically expect to see that future.More and better educated police? Someone invents an easy and safe cure for addictions? A new and better educational system? Or something like that.
But I think the most important factor is the enlargement of the circle of what we consider "us" rather than "them." For example, it's been observed that anti-immigrant prejudice is not (as you might at first assume) highest in those areas that are having practical difficulties (housing, jobs, services etc.) with a large immigrant population. For real widespread biggotry, you have to go to places that never see a foreign face and get all their information through the media and gossip. The best cure for prejudice, always, is getting to know the Other: and the most continuous technological change throughout history has been improved communication. I think these two facts come together to suggest an explanation.