In 2014, I gave a webinar entitled, “Over Threshold: The Changing Definition,” for the Pet Professional Guild (PPG). Thank you to everybody who came! That was so cool to recognize some names!

I am outlining here some basics from the webinar. The reason I created the webinar in the first place was to allay confusion in the dog community about definitions and to aid in communication. I think some straightforward definitions and a “map” will help many people and their dogs.

I argue that there are three distinct, necessary, and useful definitions of the word “threshold” in dog training. They are:

1. Sensory threshold as defined in psychology. Here is one textbook definition: The faintest detectable stimulus, of any given type, is the absolute threshold for that type of stimulus.—Psychology, Peter Gray, 5th edition, 2007. In the webinar I go into the history, discuss types of thresholds in psychology (yes, even within the discipline there is more than one), and cite several more definitions and supporting information. There are many sensory thresholds: hearing, different aspects of vision, smell, touch, etc. One way the psych definition of absolute threshold is unfamiliar to our common use of “threshold” in training is that it is the stimulus that is above or below the threshold of the organism’s sensory capabilities. We say, “That sound is under the threshold of hearing,” not, “The dog is over its threshold of hearing.” Organisms’ responses to sensory stimuli are often invisible to the naked eye, and the responses generally do not correlate to overt, “dramatic” behavior.
2. Threshold in the common training sense. You can find definitions of this usage in books by Leslie McDevitt, Debbie Jacobs, Laura VanArendonk Baugh, and more. These definitions roughly agree. Here is Debbie Jacobs’, which is very straightforward: The threshold is the point at which your dog can no longer deal with a trigger before reacting in a negative way (with fear or aggression).” — A Guide to Living With & Training a Fearful Dog, 2011. I argue that this usage of the term generally corresponds to the response of the sympathetic nervous system: the fight/flight/freeze response or the fear response. In this usage, it’s the dog that is said to be over threshold, not the stimulus. I also cover usages of the term “threshold” by behaviorists including Steven Lindsay, Dr. James O’Heare, and Dr. Karen Overall. They discuss dozens of sensory, physiological, and behavioral thresholds, and always specify which one they mean.
3. Threshold of stimulus aversiveness. This threshold is the point at which an existing stimulus becomes aversive, generally because of the intensity of the exposure. I gave this threshold a name, but I didn’t invent the concept. It is necessary to locate this threshold through our dogs’ behavior when doing both desensitization/counterconditioning protocols and operant learning processes. Jean Donaldson defines it thusly: In DS/CC, “under threshold” is: An intensity of stimulus that elicits no fear (and so the intensity of stimulus that would not function as R-)…. Not “mild fear” or “manageable fear,” it’s NO fear.–The Pitfalls of Negative Reinforcement, PPG Webinar, 2012. Attention to this threshold is necessary also in negative reinforcement protocols that involve escape, since the stimulus exposure must be over the threshold of aversiveness in order for escape to function as negative reinforcement.

I believe that most of the problems in discussion of thresholds in the dog training community are due to two major points of confusion: 1) Whether we’re talking about the dog or the stimulus being over threshold (confusion between Definitions #1 and #2); and 2) The fact that many of us haven’t realized there is a difference between Definitions #2 and #3.

Mapping it Out

Here is a graphic showing these three different thresholds, and where the major types of protocols for working with fearful, aggressive, or reactive dogs fall among them:

 This graphic may be shared for educational purposes with the copyright and credits included, and I would appreciate online citations to link back to this post or the webinar page.

The combination of desensitization/counterconditioning is performed under the threshold of aversiveness, as Jean Donaldson describes. Protocols using negative reinforcement (escape/retreat from the aversive stimulus) must take place partly over the threshold of aversiveness, or else the movement away is not reinforcing. They generally go back and forth over that threshold. Finally, flooding takes place at or above the threshold of fear response. In the webinar I split things out further and map six different protocols separately; I have roughly grouped them for this graphic.

I also talk about the ways that some of the thresholds move and change, through training, external events, and the emotional state of the dog. I describe how certain protocols become more difficult if two of the thresholds are very close. For instance, for wild animals the threshold of sensory perception of a stimulus and the threshold of aversiveness of that stimulus may be practically on top of each other. I address the often-heard claim that there is no negative reinforcement happening if the dog is “under threshold.” (Which threshold?) Also, I discuss which protocol is likely to take place closer to the stimulus—but also why the absolute distance is not a good point of comparison.

Conclusion

I will be working further on this topic, in part because of some great questions asked at the end of the webinar, so you may expect more from me about it at some point. The webinar is no longer available through PPG, but I plan to release a similar one in the future. I’m working on it in 2022.

Please note that the webinar will not have information on how to perform the above-mentioned training/conditioning protocols, on reading dog body language, or other training tips. It’s not about how to train a fearful or aggressive dog. But the feedback I have gotten from viewers is that it has clarified an area of considerable confusion and that it will help their training.

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