I have only been able to access the abstract of this article so far (darned paying work gets in the way of tracking down and reading interesting stuff sometimes), but it sounds quite interesting, though not surprising.
A study in Belgium investigated the performance of military working dogs. The dogs were divided into two groups, one trained in the traditional manner used by Belgian Defense and the experimental group also receiving a new "human familiarization and training program." The abstract does not go into any detail about what this program entailed, but the abstract intro notes that dogs can use a number of human social cues to successfully accomplish tasks.
The results state that the experimental group performed better, with better overall results and a "higher body posture" (I would guess demonstrating more self-assurance), than the traditionally trained dogs. The final sentence notes "Regular training combined with positive dog-handler interaaction is also required to increase the dog-handler team's performance."
This sounds promising, and I hope to have the time to track down the full study soon. Getting the military and police to move away from force-based training has been a tough nut to crack (despite Steve White's continued efforts), so studies like this can certainly help the cause.