"Prosecutors say jurors are telling them they expect forensic evidence in criminal cases, just like on their favorite television shows, including 'CSI: Crime Scene Investigation.' In real life, forensic evidence is not collected at every crime scene, either because criminals clean up after themselves or because of a shortage in resources. Yet, increasingly, jurors are reluctant to convict someone without it, a phenomenon the criminal justice community is calling the 'CSI effect.'"It seems a case study in the flow of culture (ideas/info/norms) down the classes (see NY Times series). Consider: well paid scriptwriters in Hollywood come up with story ideas for CSI and similar series. They're aired and the ideas/information about DNA and other forensic science get spread around. Jurors take their cues from what they've seen. Even assuming that many criminals don't watch CSI, defense attorneys learn to focus on the holes in the prosecutor's cases. Any success will get incorporated into the folklore of the "criminal street." That changes behavior.
In contrast, consider the flow of rap from the criminal street up to the top of the entertainment industry. It's certainly not the first instance of obscenity rising from its roots to become modish--I remember the reaction to rock in the 1950's. I think you can go back further to vaudeville and other entertainments that rose up.
Query--if class mobility has declined recently, can we say culture is flowing up and down more rapidly these days?