How to Raise Criteria in Shaping

Shaping—teaching a complex behavior by reinforcing behaviors that successively look more and more like your final goal--is hard to describe, and to prescribe. When it goes well, it can feel like magic--whoa, she started clicking and treating for just looking and now the dog is going over and climbing onto the thing they were looking at and sitting on it! And if you're a casual observer, it can seem very mysterious how the trainer got from phase 1 to phase 3 (to borrow a metaphor from South Park):

It's often mysterious even to the trainer who did it, leading some to refer to setting criteria as the "art" part of the "art and science" of shaping. But science informs even art--blue paint looks blue because of its chemistry, and behavior moves because of environmental conditions.

There are some guidelines floating around out there about when to start waiting for more behavior to reinforce--like when you’re reinforcing the current approximation at a high rate, say, 10-15 clicks per minute, or when your learner has offered the current approximation on some high percentage of opportunities to do so--but the problem with these is that they don’t tell you how many opportunities to give or how many minutes to train at each level, or make it clear what is supposed to make the learner go from offering the current approximation at a high rate to offering something beyond it just because you decided it's time for them to do so.

So here are some thoughts on why the next approximation might happen--and how to make it more likely to happen if it's not.

Use a high rate of reinforcement to engender “discretionary effort.” Discretionary effort is a phenomenon observed by Aubrey Daniels and others (more research needed!) in the context of workplace behavior. Daniels describes it as going beyond the minimum required for reinforcement, and attributes it to frequent positive reinforcement. A high rate of reinforcement requires easily achievable criteria, so this is the good ol' practice of splitting so you can click/treat often and keeping your eyes open for what you want to start happening.

Reinforce variability itself. Most if not all behavior is performed with some naturally occurring variability between performances (something I learned from Susan Friedman, who sends along this food for thought), perhaps the better for the environment to be able to select some variations over others. Sometimes our high rate of reinforcement approach can narrow this variability—if you reinforce a very specific approximation a ton, you’ll see more of that and less of other variations. But some very good shapers I know (cough Hannah Branigan cough) often look like they are reinforcing absolutely everything during shaping. What they may be doing is reinforcing variability itself, which gives you more to choose from--including some reps that start to look more like the final behavior. So what you can do is basically reinforce both a little above and a little below your current criterion until you see a variation you want starting to be offered. You can then start to reinforce that one more, or exclusively. (I think this is the technique that led my friend Julianna DeWillems to use a metaphor I love, "sweeping up a pile of dust," to describe shaping.)

Use treat placement strategically. I’ve written a whole other post on this, but briefly, think of your click as the next cue in a chain, rather than just as a conditioned reinforcer. Then think of the behavior that the learner will do to collect the treat as being cued by the click and reinforced by the treat. Then think about how you would chain two behaviors together if you wanted them to eventually blend: You would cue one, and when it was performed, cue the next, and then c/t after the second behavior, then repeat. Then when you saw the dog anticipating the second cue, and starting to jump ahead to the second behavior on finishing the first, you would fade the second cue out. What initially happens after the click, with repetition, will start to creep before it, and when you see that, you can delay your click until the learner has done the second behavior as well. (Note: this effect can also happen when you don’t want it to, another reason to constantly be thinking about what is happening between the click and the treat and adapting your treat placement with your end goal in mind during training, especially shaping.)

Change the antecedent conditions. Big, purposeful examples of this are introducing lures or arranging props like gates or platforms to encourage certain paths of movement, but even tiny changes can get you slightly different behavior from what you're getting now. If you have been sitting down the whole time you've been reinforcing the same approximation over and over, that context is probably cuing what you are getting now. So try kneeling or standing up, or moving to a different chair--these small changes may provoke just enough variability for you to start seeing, and reinforcing, something further along the path toward your goal, or at least to start being able to reinforce variability.

Surf the extinction bursts. This is an older technique and involves stopping reinforcement for the current criterion, or doing “twofers” (reinforcing only every other one) to spur variability. The variability here is a predictable by-product of extinction (nonreinforcement), which can also be a product of intermittent reinforcement (because it involves partial nonreinforcement). This can be done really well, but in my experience it’s harder on the dog if you have already narrowed variability too tightly and you don't change anything else about the context, or if you are waiting for too big a leap. Even if you get a variation you want to reinforce, you’re likely to get some emotional behavior (think “frustration”) along for the ride that you probably don’t want to bake in to your training by reinforcing it along with the bigger effort on the goal behavior. If you get stuck, think about changing treat placement or antecedent conditions first.

Minimizing Frustration When Reinforcement Is Not Available

I had a really interesting remote session this week.

One of my “particular interests” is in how to minimize extinction (where behavior that has worked before stops working), and its unpleasant side effects (often labeled “frustration”), in situations where at least some unavailability of reinforcement seems unavoidable.

One of those situations is persistent, long duration barking directed at a person who is not in a position reinforce something else or to simply cope with the barking. This type of barking has often been shaped up by a combination of trying to ignore (causing an escalation in intensity) and then redirecting (often with a food item). The dog learns that this situation (i.e., person is talking to a computer on the desk, guests are over, etc) predicts that now is when this type of barking is needed/will produce an outcome they want or need.

As some know, I’ve written about, presented on, and done research toward the question of how we might reduce the amount of frustration (in layman’s terms) that the dog will experience when, inevitably, a person can’t respond to their requests right away. One way I think holds great promise is to teach the dog signals for when the behavior will work and when it won’t, or when there will be a delay that they need to wait through--sort of like telling a kid "I'll be on the phone for 20 minutes; do what you want within reason but I won't be able to talk to you or get you a snack until I'm off unless it's an emergency." Since we can’t simply state “rules” to a dog, we have to teach them what the conditions for reinforcement are (and aren't) through experience. That means looking at all the “cues” that may currently tell the dog barking will work and changing them in some salient way before changing what we reinforce and when. (A lightbulb about this went off for me during a talk by Jesus Rosales-Ruiz called "Don't Fight Extinction" at ClickerExpo a few years back.)

In the conditions under which the problem already occurs, you are likely to see the dog keep trying, and escalating, because it’s harder for them to tell (especially when their behavior has worked on a slot-machine type schedule) that it’s no longer going to be effective. The change in the antecedent conditions can also become the cue for new behavior.

One approach I've tried in the past is to add something to the problem situation for the new rules to get attached to. Another, arguably less intrusive approach if it's possible is to look for antecedent conditions that already cue the behavior you want, and see if you can incorporate them into the situation where the dog barks. I discussed this idea with a new client yesterday whose dog persistently barked at, climbed on, pawed, and licked her while she was trying to talk on Zoom in her dining room. The first thing we tried was removing all the toys, treat containers, etc. from the Zoom setting, but the behavior started right away and went on for probably half an hour during our evaluation, growing more frantic. This pup leads a lovely and enriched life, with lots of off leash time and attention from his human. She had tried preventively reinforcing a settle during Zoom with treats, and giving food toys or chews in advance of calls, but as soon as the goodies ran out, the dog would go back to these behaviors, and because she was on Zoom she would feel compelled to quiet him by feeding again or refilling the toys.

After our discussion, she came up with a fantastic idea: when she cooked or baked in the kitchen, she had never “trained” her dog to settle with food; she simply had gone about her business regardless of what the dog was doing, and the dog had typically laid down near the warm bottom of the fridge or on a doormat while she worked. I loved this suggestion so much because she didn’t take away a recipe from our discussion—she took away the core concept and was able to apply it! So we moved her laptop and a chair to the kitchen island, and in 12 minutes his barking and climbing decreased quickly in intensity and he went and laid down on the doormat. I’m kicking myself for not recording the session, but above is a screenshot.

Doing Zooms at the kitchen table instead of the dining room table are a comfortable alternative for this person right away. We are also going to try to introduce a new environmental cue for the behavior, and the temporary unavailability of attention or food, in this setting that we might be able to transfer back into the dining room.

Thanks for Barking: Addenda

This 2021 blog post I wrote to elaborate on a 2017 quickie for clickertraining.com continues to be the most read thing on my website. (For the actual steps in the protocol, go to that post. Then come back and read this one.) And I get a lot of heartening messages about how it has helped people live more harmoniously with their dogs. But like most responsible content producers, I also worry a great deal about sending “recipes” out into the wild without enough context--be it through social media or presentations at conferences that are always shorter than I’d like. So here are some additional thoughts that have been percolating over the past couple years.

The number one thing people ask, with concern, about this protocol is: aren't you reinforcing barking? Initially yes. And, maybe forever. It should, however, be less barking, and less intense barking, and if you follow the protocol all the way through, you might get closer to none.

The number two thing people ask is "can I use it for x," and this is related to the number one thing. I think it's important to emphasize that this protocol is designed to address barking at stimuli that surprise both you and the dog, like stuff outside your window, in your apartment hallway, or outside a fence. If the things your dog barks at are not surprises, and you can see them coming and get ahead of barking consistently to reinforce something else, definitely do that instead. Leslie McDevitt's "Look at That" from Control Unleashed is great for this.

This protocol works best with initial preventive management, pretrained skills, and consistency. I don’t know about you, but I don’t want to do any of those things if I don’t have to. To potentially save yourself some work, if you have a brand-new dog and they are barking at stuff outside the window or fence, or your dog just started barking at sounds when you moved . . . then if your neighbors won't murder you, try doing nothing about it for a week and seeing what happens before starting any other type of protocol. I gave this advice to trainer friend Christie Catan when she moved to the country and you can read about it here.

This protocol initially uses food (usually) to reinforce barking. Less barking, and then if carried out to completion, the reinforcer is used to select a different part of the chain that results. I don’t worry about reinforcing the barking, though, because if you are a place where you are really motivated to do something about the barking, the barking is occurring regularly, which means something is reinforcing it already. The reinforcer is probably the sound or sight going away, or possibly the way you react to the barking. These explanations need to be ruled out before deciding that the barking is “self-reinforcing" as I often hear people do.

Because something in the environment is reinforcing (which means "strengthening") the barking, preventive management is key. Without it, the behavior will continue to be reinforced, and you may find yourself weakening or poisoning the cue you are trying to train (read on). Your management may not be perfect, but don’t let perfect be the enemy of better. If you are not prepared to train, do your best to minimize exposure, and by extension, opportunities to keep getting reinforced by the environment for barking. Use window film or white noise, close blinds, close the back door, put slats through or tarp over the chain link fence, etc. You may find this solves your problem without further training, but maybe you also like to be able to look out the bottom half of the windows and still want to move ahead with some training.

This may sound similar to advice you have heard about training a recall--don't put yourself in a position where you'll need it if you don't think it will work, right? Well, a clean recall cue is the main prerequisite for this protocol. And “thank you” is that clean recall cue. It doesn’t have to be “thank you,” but most people have ruined their first recall cue already (by not reinforcing, reinforcing poorly, punishing late arrivals, only using it when it will cost the dog something to come, etc), and most people haven’t ever said “thank you” to their dog yet, so it usually has no prior associations. It also tends to work as a mindset changer for the humans; it’s hard to say in a mad tone. But you could use anything that is a 100% reliable predictor of stuff your dog loves--even, gasp, your marker signal. A marker is just a cue that means come get your reinforcer.

If your recall isn’t working yet and your management fails, go to your dog and deliver the treats anyway. Drop them, many of them, in a straight line to the ground right past her eyeball. (Don't try to shove them in the dog's mouth; dogs are often less likely to take them that way, and you may get bitten.) When I started this protocol with my own dog Pigeon, my recall cue was not working in this situation, and I hadn’t thought of retrraining a new one “thank you” yet. When she tore down our gangway to hurl herself snarling at the gate, I hustled after her and stood right behind her, gave the cue, and then fed handfuls of Stella and Chewy’s if she so much as gave me a dirty look. Now, I would feed regardless of whether I got the dirty look. After a few sessions, she was paying much more attention to me when I followed her, both her barking and her visible physiological reactions (e.g., piloerection) got less intense, and I was able to start successfully recalling her out of the barking from farther away.

As with any other recall, I don’t recommend adding punishment—intentional or inadvertent—after the "thank you," as you risk poisoning the cue. If your dog won't take the treats even at the location of barking and you absolutely must bring them away, do it—but then adjust your plan, including preventive management, so you are not routinely hauling them off by the collar after you have said “thank you,” which could turn “thank you” into signal for avoidance. If you think "thank you" won't work, don't say it before you go get them.

I like to have the treats (and any other reinforcers) that follow “thank you” come in a predictable location so that (a) you don’t have to have treats on or near you all the time and (b) the dog will anticipate the location and start heading there—but if that’s not practical, the location can just be you.

Reinforce the earliest response your dog has to the stimulus. Don’t wait for barking if you can catch the head swivel or ear flick toward the sound.

Don’t reinforce the same type of (same look, same sound, pointing in the same direction) barking if it is offered when there is no stimulus to bark at. I once met a dog who barked at people outside the window, but also appeared to have learned to go around barking at windows even with nothing outside in order to get his person to get his toys out of hiding. That’s the sort of problem you may create if you reinforce the barking when there is no stimulus outside.

If the dog really is barking at surprise stimuli to get treats, congratulations! Many people seem to be happy to just have a nice way to stop barking quickly, before the thing goes away, but to me the coolest part is that now you can use the treats to shape less barking and faster turning. With Pigeon, I had trained up a predictable pattern of start toward the fence, bark a few times--here's the recall!--then turn around and start looking for the treats. So I began to delay the recall until I saw that turn. She started to bark even less and turn faster—skipping ahead to the behavior closest to the reinforcer.

The other things that may be happening are that the aversiveness of the stimulus may be reduced through the pairing with food (which you may not see if you are also routinely hauling your dog away by the collar after the cue); that when the stimulus starts to go away even without the continued barking, it may reveal barking to be unnecessary to remove the stimulus; and that if your response was reinforcing barking, the dog now gets attention or treats from you for less barking or for other behaviors like turning.

Pro Tips: Strategic Treat Delivery

One thing that distinguishes basic from excellent positive reinforcement training is reinforcer delivery. You may be hearing a lot about this in the dog world lately, including Mary Hunter's brilliant demonstrations of building "reinforcement systems" for more effective teaching (she's cohosting a summit on the topic, registration for which closes today), as well as Hannah Branigan's presentation on how to build what's often called "drive" and Eva Bertilsson and Emelie Johnson Vegh's presentation on "starting points" at last week's ClickerExpo.

Here are a few practical considerations and tips that I originally wrote for my professional students in the Karen Pryor Academy on how to thoughtfully deliver just one of the many types of reinforcers that positive reinforcement trainers can use: food, aka "treats."

The delivery of the reinforcer (e.g., the treat) for the behavior that just happened is also the antecedent for whatever the dog is going to do next.

So consider how to deliver the treat so that when the dog is done eating, they are perfectly in position to offer the next thing you want to see.

Some simple examples:

• Want the dog to be ready to move its feet toward a target again? Deliver the treat away from the target.

• Want the dog to remain in position and offer eye contact after eating? Deliver the treat right to the dog's mouth so the dog’s front feet don’t move.

• Want the dog to immediately walk a few more steps by your side? Deliver the treat at your hip or slightly behind.

• Dog shoots ahead after each treat? Toss the treat for attending to you or walking by your side out into the grass, then walk forward and wait for attention or movement to catch up.

• Want the dog to look at a surprise trigger from a little farther away? Toss the treat for the first glance (or have the dog follow it a few steps) in the opposite direction from the trigger.

Behavior between the marker signal and the treat will also be reinforced—and after a lot of predictable reps, you may start to see it occur in anticipation of the marker instead of after it.

So consider how to deliver the treat to avoid things you don’t want between the marker and the treat, and encourage things you do.

Some simple examples:

• If you don’t want a puppy to jump up your leg between the click and the treat, preload your treat hand and deliver treats quickly to the floor after the click. This leaves no time for jumping, and no reason because it’s wasted effort if the treat is predictably going to appear down low. You'll then be able to move the treats back into your pouch once the puppy is waiting down low.

• If you don’t want a dog to curve in front of you every few steps on a walk, deliver treats from the side of your body that the dog usually walks on, rather than bringing them across your body with the opposite hand.

• If you don’t want your dog to turn toward you after going over a jump, mark as the dog begins the jump and send the treat (or toy) in a straight line ahead of them.

• If you'd like your dog to start to sniff when they see another dog, then mark for looking at the dog and sprinkle your treats on the ground rather than handing them to the dog. Your dog will likely begin to look down on hearing the marker, and may then begin to look down on seeing the other dog.

How you deliver reinforcers can add value to or subtract value from the reinforcer itself.

So consider whether:

• Your delivery might be boring: for instance, offering a treat (or toy--this is a common problem in tug) by holding it still rather than moving it away from the dog.

• Your delivery might be aversive, e.g., shoving food into the dog’s mouth or backing a dog up with the treat.

• Your delivery is getting delayed because the dog didn’t see where you tossed the treat or it went under something.

• Conversely, sniffing around in the grass for a treat might add value in some situations.

• A bowled- or “catch”-type treat delivery might be more exciting than a treat delivered to mouth (I often like this for helping food compete with birds and squirrels!)

You may want to change where you deliver the reinforcer at different points in your training of a behavior.

If you deliver in the same place every time without thinking about it, the behavior is likely to drift in the direction of reinforcement delivery. So be ready to watch behavior and constantly adjust.

Examples:

• If you toss your treat to reset every time you click down, your dog may start to pop up in anticipation of the click, or not lay down all the way. You can fix that a number of ways, including being more careful with the timing of your click, but another way is to begin to deliver the reinforcer in place once the dog understands that the behavior is to put their torso on the floor.

• When I attended Bob Bailey's chicken workshops, one exercise was to shape a chicken to walk a figure-8 around two cones . . . after shaping them to walk an oval around them. I clicked and treated a lot for the first step the chicken took to cross through the center, and after a while the chicken would pause there and glance back at me.

• This can be used for good as well as for evil; if you want to teach a dog to shift its weight back when it reaches a threshold (like a door or curb), mark them for arriving at the threshold and deliver the treat behind them.

Consider teaching the dog how a treat will be delivered in a given session before starting to work on the goal behavior.

• The click is frequently talked about as a conditioned reinforcer, but it may be better thought of as a cue to do whatever behavior is required to collect the treat or other "terminal" reinforcer.

• When cues are not clear, their value as reinforcers is weakened. So make your cues about where reinforcement will be delivered clearer.

• Let’s say you are going to click and toss a treat behind the dog. Start with just that—reinforce the default stand, say, with a click and a clearly telegraphed toss to a spot on the floor.

• Once the dog has that pattern, then add in your cue for the established behavior you want to work on, or start capturing or shaping a new behavior.

Check back later; I'll try to add videos to illustrate these various suggestions. But I wanted to get the post up today in case anyone wants to sign up for the Behavior Explorer event.

How to Teach a Dog That the Store Is Closed, Redux

What happens in the three-part video below doesn't look too eventful, but for this dog and his owners, it was a big deal.

Oliver had a history of intense barking at his owners when guests were present. These awesome, dedicated guardians had taught him to go to a mat when guests arrived—which was a great incompatible response to jumping on them—but he still barked from the mat while they were visiting unless food was delivered at a fairly high rate. During our first meeting (which was actually about training for his sibling) it was hard to carry on a conversation over his barking.

I don't know why this behavior first occurred, but by the time I came into the picture, it appeared that the barking was likely reinforced by the opportunity to do mat training! (Note: This means that what we did for Oliver may not be what you should try for your dog who barks at guests. If you don’t know why your dog is barking, please work with a professional to assess it and make a customized plan based on that information.)

In the first clip below, with a guest over (me), Oliver is quiet on his mat (as noted below, the first thing we tried was to build duration for that). In the second clip, his mat has been removed, and he begins to bark and look at his dad. In the third clip, his mat is removed, but a towel is placed on a doorknob, and Oliver never barks as he lays down next to his mom, solicits petting from the guest, and (delicate sensibilities warning) demonstrates why one of his nicknames is “the egg man.”

In my experience, it's not unusual for dogs to learn to bark at their owners only when guests are visiting . . . or only when they talk on the phone . . . or, as many of us saw during COVID lockdowns, only when they work over Zoom. That's probably because owners may not reinforce barking consistently when they are home alone with the dog, but may feel extra pressure to do something to immediately quiet a barking dog when they are interacting with another person. The dog may then learn that this is when barking is the most effective way to get a need met.

Often when we repeatedly redirect the dog, rather than arranging the environment proactively to preempt the unwanted behavior, we can actually end up "training" the unwanted behavior in this way. (See: Redirect or Preempt? and Thanks for Barking 2.0.)

This blog post I originally wrote about what we ended up doing for Oliver, back in 2019, got eaten by gremlins (read: I tried to edit it and accidentally deleted most of it) shortly after I put it up. So I’ll sum up quickly here: As previously noted, we first worked on adding duration to a quiet down behavior on the mat. Oliver’s people did an amazing job of this, working up from almost no duration to 15 minutes of quiet between sessions! However, this still felt unsatisfactory—Oliver and his humans were both actively “working” when guests were over, and nobody could just relax and enjoy interacting with the guests, which is the whole point of having guests.

So ultimately, we taught him (a) that when a towel was tied to the doorknob, barking would no longer produce food, specifically the opportunity to earn food by going to his mat, or any other response; (b) when the towel was up, nonfood reinforcers were available for other behaviors, such as petting for approaching a guest, or proximity to a person for hopping up on the couch next to them—both things Oliver seemed to enjoy in other contexts). In the short term, we also used exactly what he was barking to get—food, delivered during mat training—to reinforce the absence of barking for a certain amount of time. Probably thanks to the other reinforcers available, the owners were able to fade the food out, and the last time I checked Oliver was still able to hang quietly and interact with guests without any mat training, and also without the towel.

I have since tried similar procedures with other clients whose dogs barked persistently for food in certain situations, including one case study I presented at ClickerExpo Live in 2021 (as part of Susan Friedman’s talk), as well as with three such dogs for my master’s thesis, Signaled Differential Reinforcement of Other Behavior to Address Excessive Vocalization in Dogs (which should theoretically be available via Proquest, though I can’t find it in search results yet). I hope to write more about that here in the future. In the meantime, though, I have finally found time to try to reconstruct this post.

Around the time of the original publication, I received a polite and important private request for clarification, which I thought would be beneficial to answer at some length in public. Part of the question was essentially, did I use extinction while the towel was on the doorknob?

The answer is yes: The behavior of barking was put on an extinction schedule in the presence of the towel, which in English means that while the towel was out, the owners did not attend in any way to Oliver's barking. Previously they had redirected him to other behaviors when he barked, and more recently if he barked they had waited for some period of keeping his mouth closed and then reinforced quiet. While they had made huge progress on building duration for quiet behavior, (a) it's possible they were actually reinforcing a sequence of behaviors, bark and then be quiet for increasingly longer, and (b) taking this approach still meant that both Oliver and they had to be training when guests were present.

The reason I felt this was important to answer was that, generally speaking, effective and ethical teachers try to minimize both the use of extinction and the negative side effects of extinction when they do use it. The sudden unavailability of reinforcement for a behavior that has been reinforced a lot in the past can be really hard for both the teacher and the learner. If you execute that incompletely or inconsistently, e.g., withholding reinforcement at first but then giving in when (predictably) the learner initially intensifies his efforts (a phenomenon called an "extinction burst"), you are likely to make the unwanted behavior more intense and more persistent. If we had implemented extinction with Oliver without a clear new signal (the towel), I think it's likely we would have seen a pretty big extinction burst, and that all the humans involved would have been quite discouraged by it. (For more on the problem with "ignoring" behavior as a standalone solution, see: The Problem With "Ignoring" Unwanted Behavior.") However, I can't say for sure (and my master's thesis didn't entirely answer the question of how important the new signal was either).

The best time to prevent reinforcement for an undesirable behavior is the first time it happens. If a mystery button appeared on your desk tomorrow and you pressed it, and nothing happened, you probably wouldn't press it again. But if you pressed it and $100 floated down from the sky, you'd damn sure try that again, and probably not give up the first time it didn't work.

After a behavior produces some desirable or useful outcome, not only will it become more likely, but it will become more likely in the context in which it worked. That context is what will come to tell the dog (or person) that reinforcement is likely for that behavior now. E.g., if your teacher asks a question in class for which you have the answer, and you raise your hand, and the teacher calls on you, you may be more likely to raise your hand in the future--but not randomly. You will be more likely to raise your hand when your teacher asks a question, and you have the answer. That's the controlling context.

Oliver didn't bark randomly. He didn't do it when the owners were sitting around in their living room by themselves. He didn't do it outside when the owners visited with people on the street. He did bark when food was being prepared in the kitchen, so food was likely a cue as well as a reinforcer for barking. Guests in the living room were definitely part of the context controlling barking, as were the mat, the treat pouch, the treats, the clicker, and probably even things like the owners' posture or gaze. The first thing I tried was simply removing as many of those cues from the environment as possible--no food, no mat, no clicker, no treat pouch, etc. But guests alone were enough to cue Oliver that barking would work, and we could not remove that cue.

So, you could say that the intention of adding the towel was intended to give Oliver's owners a new "first time." We couldn't change the context by subtraction, but perhaps, I thought, we could add something to that context that would get associated with the new rules for reinforcement.

Some other key details (note: this post should NOT be taken as complete instructions for the procedure):

(1) We started with what I intended to be a low, achievable criterion (30 seconds), and ended up shortly making it even lower (20 seconds), so we could show Oliver very quickly that if he didn't bark during that time, the training setup would reappear. It is likely bringing out the mat and treats, etc., previously reinforced barking; we needed Oliver to see they were available for doing other stuff. Today, I would probably start with just 5 seconds or maybe even less to reduce error. You can also figure out what your first criterion should be by taking a baseline: how long can the dog currently go between barking episodes in the problem context? Make it shorter than that.

(2) If Oliver did bark during that time, all that happened was the clock was reset. There was no pointed sighing, harumphing, or turning away from him to "ignore" (those types of things can actually become cues, and therefore end up reinforcing the behavior); people just kept doing whatever they were doing when he barked. And then it took a little longer for the training setup to come back.

(3) In the presence of the towel, pretty much any other behavior could make things happen that Oliver was known to enjoy in other contexts. He could sniff, look, lie down, jump up on the couch, approach a person, sit next to a person, etc. And while food was off the menu, talking, petting, looking at Oliver, smells, and maybe even a reprieve from interaction were all readily available for a wide range of desirable, behaviors that he already knew how to do. When the time criterion was reached, that stretch of alternative behaviors was additionaly reinforced by the owners bringing the mat back out for a quick round of training with food.

When you have many paths to reinforcement, it probably doesn't feel so harsh if just one of them is not available. A clear signal that reinforcement is not available can likely reduce “frustration” if it's used combination with, and/or doubles as, a clear signal pointing to alternatives for which the animal already has the required skills. Your "closed" sign should say not just, "Sorry, this store is closed" but also "the one down the street is open until 9," and your learner should already know how to get there.

An update on Oliver's behavior with guests: