This lecture was about screen violence and how it acts as a genre marker. Genre markers are anything that has been repeated over and over again that it is a tell tale sign of a specific genre. Violence is not a genre marker of one genre, but many because of the way it is portrayed. If we take 4 genres; sci-fi, spy, western and pantomime, we can distinguish each specific way violence is used, and by using that find how it acts as a genre marker.
I'll use daggers to illustrate the point, a panto villains dagger would be rusted and jagged with jewels in the hilt. This is because the panto villain nebver succeeds in stabbing someone so they choose a dagger design that looks as evil as possible while still being over the top and sillyy. A cowboys dagger on the other hand would be very clean and practical with a simple but perhaps personalised hilt. When an audience sees a dagger like either of these in a film they instantly know what sort of film they are watching.
The sort of scene the cowboy knife would be in would go something like this, an Indian breaks into his ranch and attacks him and his innocent family, the knife is used as an absolute last resort to either kill or pin the red indian against the wall by his clothes.