Note, I do not work my dog in SAR, but I think finding motivation for your dog to perform is pretty much the same across all types of sports/work.
I do compete in agility, though. First, you must find out if your dog is more motivated by food, or more motivated by toys. My particular dog is, hands down, the most motivated by food, so that's what I use. When we started agility, we weren't looking for perfection. My dog was heavily rewarded for simply attempting to take a single obstacle. Every jump earned a reward, every contact earned a reward.
As we learned and started trying to string obstacles together, the dog eventually finds doing the obstacles and working with me rewarding, as well. The frequency of rewards began to decline. Instead of simply attempting an obstacle, rewards were only given when an obstacle was completed correctly (such as in contacts, all four of your dog's feet must touch the bottom colored area to make it "legal", otherwise you get a point docked). You cannot give rewards on the course when at a trial, so the dog must complete the entire thing correctly without rewards! (although they certainly get a nice treat when they get off the course and get back to their area)
If I am reading what you wrote correctly, it sounds like you're dog is new to SAR. Instead of focusing on perfection, work to ensure your dog finds the work itself fun and rewarding. Then, when you know the dog loves to go out and do SAR, you can start refining the skills. So, maybe that's as simple as instead of the decoy being silly and fun, you're silly and fun and give the dog his reward for finding the decoy.
Also, if this is a young dog, foolishness and being silly is kind of normal, haha. I imagine he'll begin to become more level-headed as he matures.
I do compete in agility, though. First, you must find out if your dog is more motivated by food, or more motivated by toys. My particular dog is, hands down, the most motivated by food, so that's what I use. When we started agility, we weren't looking for perfection. My dog was heavily rewarded for simply attempting to take a single obstacle. Every jump earned a reward, every contact earned a reward.
As we learned and started trying to string obstacles together, the dog eventually finds doing the obstacles and working with me rewarding, as well. The frequency of rewards began to decline. Instead of simply attempting an obstacle, rewards were only given when an obstacle was completed correctly (such as in contacts, all four of your dog's feet must touch the bottom colored area to make it "legal", otherwise you get a point docked). You cannot give rewards on the course when at a trial, so the dog must complete the entire thing correctly without rewards! (although they certainly get a nice treat when they get off the course and get back to their area)
If I am reading what you wrote correctly, it sounds like you're dog is new to SAR. Instead of focusing on perfection, work to ensure your dog finds the work itself fun and rewarding. Then, when you know the dog loves to go out and do SAR, you can start refining the skills. So, maybe that's as simple as instead of the decoy being silly and fun, you're silly and fun and give the dog his reward for finding the decoy.
Also, if this is a young dog, foolishness and being silly is kind of normal, haha. I imagine he'll begin to become more level-headed as he matures.