Nova Science: How Smart Are Dogs? Shows dogs use cues from their masters to pick the correct objects, how are "Drug Dogs" influenced?

Dogs being cued by their masters so they will pick the correct objects, a dogs desire is to please it's master! This raises red flags for "Drug Dogs" in police departments and how they might be influenced.

Link:http://www.pbs.org/wgbh/nova/nature/how-smart-dogs.html