The confusion about the KGS exists because of the varied uses of the term Keep Going Signal that appear in popular training literature. When researching my original 2009 article on the KGS, I found dozens of references to the tool being used in diverse scenarios, including with circus animals (Kelley, 1946), guide dogs (Landeman 1971), search and rescue (Pryor, 1999), zoological training (Cover, 1991), and military applications (Bailey, 2007). While there were similarities between a few of the uses, the differences in some cases were striking.
Normally, we can turn to the scientific literature to help clarify terms. However, there is no reference to a KGS in the currently available peer-reviewed journals. The KGS is a popular-use term, not a scientific one. Thus, trainers can use a KGS and define it almost any way they like; it would be hard to argue that they are wrong. In this article, I’d like to focus on the two most commonly used applications of the KGS.
The most widely used version of the KGS is as a conditioned reinforcer, used to reinforce an animal partway through a long-duration task, such as a medical behavior, guide-dog work, or search-and-rescue efforts. When an animal is performing the desired behavior correctly, trainers use the KGS to indicate that the animal is meeting criteria and should keep going. If the KGS becomes a predictor of a marker signal (a secondary reinforcer), then, technically, the KGS is a tertiary reinforcer.
KGS as a tertiary reinforcer