A few years ago a search-and-rescue trainer named Sharon asked me to help problem-solve a perplexing case. Her dog, an energetic five-year-old Lab mix named Carson, suddenly stopped alerting when he found a person during search trials. Sharon and Carson were a FEMA-certified team that successfully found and helped rescue dozens of people over a two-year period. Normally, Carson began his searches with great enthusiasm, running through the rubble, the field, or the specified search area, clearly on a mission. Sharon could tell when Carson found the scent of a person and was zeroing in on the exact location, because his search pattern changed; he sniffed in a more focused way, and soon after alerted on a find, barking excitedly and looking directly at the location of the missing person.
At Carson’s last real search, when Sharon knew he had acquired the scent and expected him to start barking, Carson kept circling a small area, sniffing and looking toward a fallen beam blocking a doorway, but never actually stopping to indicate. Sharon started calling out to see if anyone would respond, and she heard the faint yell of a person deep within the rubble. She called the rescue team, and a young man was carried out from the rubble safely.
Sharon pulled Carson from active duty temporarily. In retrospect, she had seen a decline in his enthusiasm for alerts on the previous three or four practice searches, though he still alerted successfully. She was concerned by the change in his behavior. Carson was given a clean bill of health after a veterinary visit. He loved training, and always seemed eager to go out on searches. At the start of all searches, whether they were practice or real, Carson began with enthusiasm and vigor, just as he had always done. “Searching for people” had been trained as a game, and it still seemed to be an activity he enjoyed. It was only the alert that was breaking down.
The cause of the breakdown was not immediately obvious to us. I asked whether Carson had been frightened by a victim on one of his recent searches. Lost or trapped individuals often are startled by the sudden appearance of a dog turning the corner, and they scream or yell, or even lash out and hit the dog. That type of reaction by the victim can make the dog less eager to alert, understandably. I also worked with a dog that, for the first time in his life, found a dead body. The dog was not a human remains search dog, and the find seemed to depress him and make his interest in searches diminish. Sharon assured me that none of these things had happened to Carson.
When a behavior breaks down, it either means that it’s being punished inadvertently, or that it’s not being reinforced effectively. Sharon didn’t feel that any of the punishers I asked about had occurred. Since there were no obvious aversives, we focused our attention on the reinforcers. After making a successful find and alert, Sharon played a vigorous game of tug with Carson. Sharon and Carson demonstrated the tug game, and it was clear from Carson’s behavior that he enjoyed the game and found it reinforcing. Tug was a high-value reinforcer in other situations, and Carson seemed to enjoy the activity of searching. So why had the alert vanished?
I was reminded of a similar experience I had with highly motivated law enforcement dogs. The dogs were so eager to search for the odor that they didn’t want to quit. The search was so highly reinforcing that ending the game became aversive. As I shared that story, Sharon realized that this might be the problem for Carson. On her last four real searches, they were looking for a single lost victim. Immediately after the find, they played tug, Sharon leashed Carson up, and put him in the car for the ride home. As much as Carson enjoyed the game of tug, it may have become an indicator that the searching game was over.
We began to retrain the behavior. We started each practice search with a two-minute game of tug, and then cued Carson to begin his search. When he found the hidden person, we rewarded him with more tug, and then cued him to search again for another hidden person. Within just a few repetitions of this game, we saw Carson’s excitement for the alert return. The alert didn’t necessarily mean the game was over! The alert always meant a fun game of tug. And tug, more often than not, meant there would be more opportunities to search. Within a few weeks, Carson’s alert behavior was stronger than ever. Carson continued to work successfully for several more years. He and Sharon were responsible for finding and saving more than 100 lives -- a very successful team!
Since that experience, I have seen similar scenarios occur over and over again, particularly in scent-detection work. The game of searching for scent is highly reinforcing for most dogs. A toy, game, or treat is needed to reinforce the alert behavior, but trainers must be careful not to make these toys predictably signal the end of playing the sniff game. Otherwise, it can turn the toy, game, or treat into an aversive experience.
This is a reminder that what we think is reinforcing may not be a reinforcer in all situations. We must be good observers of our learners’ behavior. If we see increased enthusiasm and continued focus on a desired behavior, we know that our reinforcers are effective. When we see the behavior change and the interest or enthusiasm diminish, it means an aversive has entered the picture, and possibly devalued the power of the previous reinforcer. We can never be complacent. Behavior is fluid and always evolving. We must remain vigilant to ensure that our animals are provided with clear and useful information.
After the publication of this letter, the SAR forums began to question the veracity of the statement “He [Carson] and Sharon were responsible for finding and saving more than 100 lives -- a very successful team!”
Admittedly, this is an incredible number of finds, even for a very prolific search-and-rescue team. As a disaster search-and-rescue team, Sharon and Carson were often called to sites where many people might be trapped in a single search area. On one occasion, they were the first team to respond to a tornado-devastated building and they were able to make finds that each included dozens of trapped people. On that one day, they located three separate groups of people totaling 62 individuals. Similarly, Sharon and Carson were called in to several major disasters that included several days of searching; they found three to five people in each of those searches.
I hope this additional information puts the number “100” into context.