Clicker training gets its name from the use of a clicker (or click) to mark behavior, but that doesn’t mean that a clicker is the only effective way to mark behavior. A clicker is just one of the most frequently used options because it is short, salient, and produces the same sound every time (mostly…). It also has the advantage that it’s a novel sound for most animals, so there are no previous associations.
When I learned to clicker train, I started with a box clicker, then discovered i-clicks (from Karen Pryor), and finally tongue clicks. A tongue click is the “klock” sound I can make by pushing my tongue against the roof of my mouth. It is very useful if I am doing training where it would be difficult to hold a clicker, or I find myself in situations where I don’t have a clicker. It can take some practice to be able to produce a consistent and reliable tongue click, and I spent about 6 months practicing in the car, while doing dishes, laundry, etc. until I could reliably make a clear and consistent sound every time.
For a long time, almost all of my clicker training was done using clicks (either with a box clicker/i-click or tongue click) and treats. And for the most part, it seemed to work just fine. The one exception was that I did use a verbal marker for my foal so that he had a different marker than his mother.
But, as I did more reading, learned more about training with other species, and was exposed to more animal trainers via the internet, I kept hearing that the click was only needed for teaching behavior and that other markers could be used to mark and reinforce already trained behavior. Not only that, they should be used, because using the click for everything could make it “dull,” and it should be reserved for use as a precision tool.
Still, I was reluctant. One of the things I liked about using a click was the clarity it brought to my training, both because it was precise, and because my horses never expected food from my hand unless I clicked. I felt that keeping the rules about hand feeding very simple and consistent contributed to the polite manners that my horses had around food. So, I played with using alternate markers (verbal ones) a little bit, but then put the idea aside and moved on. Honestly, I just couldn’t see when they would be useful, especially since I was already using a tongue click.
Then, a few years ago, when I was taking Kay Laurence’s IDTC course, I found myself reading about using different marker signals again. This time, the context was a little different because it was in a series of discussions about using secondary reinforcers. The idea was that it was useful to have different markers that were associated with different reinforcers, and also that different markers could be associated with different types of behaviors, training sessions, or different emotional states. So, this was about having options that would allow the trainer to choose the appropriate marker/reinforcer pair that would support the behavior she was trying to train or reinforce.
Since then I’ve started using a variety of marker signals at various times in my training, and have found that they can be useful. I started very simply by just introducing one new marker and reinforcer combination to one horse and exploring how well it worked under different conditions. Then once I could see where it was helpful, I tried it with a few other horses and learned when it was beneficial to use a click and treat and when other combinations could be used more effectively.
I do want to mention that the term “marker signal” is one of several terms that are used to describe a stimulus that is used to identify what behavior is being reinforced. You may also encounter the terms event marker and bridge. For the purpose of this article, I am lumping them all together in the same category.
I still feel a bit like I’ve only dipped my toe in the water on this subject, but I think it’s worth exploring further because anything that expands my ability to communicate with my animals and choose appropriate and varied reinforcers is a step in the right direction.
If you are intrigued by the idea of using a different marker or using several different markers, here are some basic tips for choosing and using them.
Types of marker signals:
A variety of different marker signals are used by animal trainers. In dog and horse training, a click is the one I see used the most, but other types of markers are common with other species. They seem to be associated with different species or broad categories of training (marine mammals, zoo animals, birds, dogs, etc.). Some of it may be tradition, as that type of marker signal was what was first used, and has continued to be used, even as the training has grown to include other species or applications. Some of it is that there are some marker signals that are going to be more suited to working with different species or in certain environments (underwater vs. land vs. in the air).
Here are some of the more common marker signals that are used:
- Verbal (words, letters –“x” is one that is sometimes used)
- Visual (lights, thumbs up, hand gestures)
- Tactile (touch)
- Other sounds (bell, beep, etc.)
Qualities of a good marker signal:
Although there are different types of marker signals, they all share some common qualities that I’ve listed below. Not every marker signal needs to meet all these categories and it will depend partly upon if you are planning on using the marker to shape behavior or to mark already trained behavior.
- Short (with some exceptions)
- Salient (stands out from the environment)
- Can be reproduced consistently (same tone, duration, intensity)
- Does not convey emotion
I do want to mention that there is one hypothesis that the click is such an effective marker signal because of how it is processed in the brain. Karen Pryor thinks that the click goes directly to the amygdala, which means it has a more direct route than a stimulus that has to go through the “thinking” part of the brain. I haven’t seen any research studies that look at this, but if you want to read more it, you can read Karen’s article at http://www.clickertraining.com/node/226.
Reasons to choose a different marker signal:
To keep things simple, let’s assume your usual marker is a click. Why would you choose to use or switch to using a different marker? If your usual marker is not a click, then you can just substitute in the name of your marker where I have written “click.”
- A click is not the best choice because of the individual animal’s needs. An auditory marker is not going to work well with a species that has poor hearing or an individual who is deaf. Some animals also startle or become fearful when hearing the sharp sound of a click.
- I am working with multiple animals and using the same marker signal for every animal could create confusion. I routinely click horses in small groups, but only for known behaviors and there are usually context cues that help them identify whose behavior has been marked. If I needed to train new behaviors with multiple horses, it might make sense to use a different marker signal for each horse.This is what I did with my mare and foal. My mare had already been trained with a click, so I chose to use a verbal marker with the foal. Would they have figured it out if used the click for both? Maybe, but my mare had previously been aggressive toward me and I didn’t want to risk doing anything that would create confusion and frustration.
- In some cases, a marker signal can accidentally become associated with an unwanted emotional state or even become a cue for unwanted behavior. In these cases, it’s usually simpler to just choose a new marker, rather than trying to change the previously learned association.
Reasons to teach additional marker signals:
This is the part that I find interesting because it’s about looking at different ways to mark and reinforce behavior and seeing if adding additional markers can improve communication.
When I first read about not using the click for everything, the general argument was that it was better to save the click for precision shaping. I think my horses are good at figuring out when I am clicking for trained behavior and when I am shaping a new behavior, but it does bring up the interesting question of whether or not we are thinking enough about what the marker signal means to the animal.
Is it really just about marking behavior and indicating reinforcement is available, or does it convey more information to the animal? I think the answer is yes, and here are some examples where using a different marker can provide additional information to the animal.
- If different markers are paired with different reinforcers, or even types of food delivery, then the marker provides information about what to expect and how to get it. The most common application of this is using secondary reinforcers where a different marker is associated with a different secondary reinforcer. You can also have a marker that is associated with a variety of reinforcers. I do have a different marker I use during riding if I don’t want my horse to stop within a few strides of hearing it. This gives me the option of marking the behavior and then using other reinforcers.
- Different marker signals can become associated with different emotions, levels of activity. A lot of clicker trained animals learn to associate the click with “doing something” and hearing the click brings up their energy level. This can make it difficult to use the click to mark calm and stationary behaviors, especially if I am trying to build duration. One solution is to not use the click and to use food directly. Another option is to use a different marker that is only used for calm behaviors.
- Some behaviors do not require precision markers. Using a click without careful attention to the effect it has on the whole behavior can lead to some distortion of the behavior because the animal will become too focused on some small element of the behavior. I have found that there are times when having a less precise marker will actually work to my advantage if I prefer to have the behavior more loosely defined. I think my horses have definitely picked up on this and they adjust based on whether I click or use a more general marker.
- Having another more discrete marker can be helpful if you plan to take your clicker trained horse out into a less clicker friendly environment. I regularly take my horse to traditional horse events and I find it is easier to use a marker other than the click. In most cases, I still feed treats (if not, I find some other form of reinforcement), but I use either a verbal or tactile marker. I’m pretty sure that when I switch to using my alternate markers, my horse knows this will not be a normal clicker session and adjusts her expectations accordingly.
If you are new to clicker training, I’m going to suggest that you stick to using one marker, a click unless another marker would be more appropriate. There is a lot of value in keeping things simple and I do think that exclusively using a click promotes good manners around food and is clearer to most horses.
But…if you’ve been clicker training for a while, I hope you will start to think about the possibility that there may be some benefit to having additional markers. It’s very easy to teach a new marker signal by pairing it with your reinforcer, and if you’ve been clicking long enough, you’ve probably had it happen by mistake. I find that once animals learn that marker signals exist, they are quick to pick up on patterns that predict food or a click so adding a new marker is easy.
I do want to make a few comments about verbal markers. While they are sometimes the most practical to use, I find that I have to be very mindful of how and when I use them. It may just be me, but I find that once I give myself permission to use words as markers, I become a little sloppier about when I use them (compared to a click) and I have a tendency to talk more during training. This is not necessarily a bad thing in every situation, but I definitely take it into account when choosing what marker to use.
Verbal markers seem to work better when they are spoken in a way that is different than normal conversation because it makes them easier for the horse to recognize them. This is important if you use a lot of verbal cues. One of the verbal markers I have used is the word “yes,” and I said it in a higher tone of voice and quite quickly, so it was more like a sound than a spoken word. I have another verbal marker that I use and when I say it, I use a lower voice and hold it for longer than a normal word. I’ve heard (second hand so don’t quote me on this) that one creative rider used clearing her throat to mark behavior in competition where speaking was not allowed.
While I am suggesting it may be useful to have more than one marker, I do think that there’s probably a point at which more is not better. Too many markers or marker/reinforcer combinations might get confusing and is probably unnecessary for most training. With my horses, I have four markers; the mechanical click, the tongue click, and two verbal markers. With my dog, I also have a hand gesture that functions as a marker, but I found this was more difficult to use with my horses since I move my hands around more in training. It’s been interesting to see the effect of different markers and I may add some more as time goes on, but at this point I’m having success with the ones I am using and will stick with them for a while.