Overshadowing in Canine Coaching: Why You Have to Know About It


A white dog with brown ears is sitting in front of a woman dressed in jeans and a blue tee shirt, whom we see from the waist down. Her hand is in her pocket and her dog is staring at the pocket with an eager look.
Why is Lewis gazing my pocket?

What Is Overshadowing?

The time period overshadowing has a long-established which means in classical conditioning. The next definition is a little bit technical, however I’ll clarify in the remainder of the piece.

Overshadowing happens when two stimuli are classically conditioned on the identical time. Typically, the stimuli are of various sensory modalities. An instance can be a visual mild and an audible sound. When they’re conditioned concurrently, one stimulus could dominate and be extra strongly conditioned than the opposite. It is without doubt one of the many issues that may trigger a classical conditioning protocol to fail or be weak.

So the above definition could make sense to all readers, I’ll first evaluate the distinction between operant conditioning and classical (Pavlovian) conditioning.

In operant conditioning, there’s an antecedent, a conduct, and a consequence. For instance, I cue my canine to come back to me (antecedent). My canine runs to me (conduct). I give my canine one thing terrific (consequence). Most of us are acquainted with this type of studying.

In classical conditioning, no conduct is required of the animal. We pair one thing the animal is detached to or anxious about with one thing the animal loves. We do that step by step at intensities that don’t scare the animal. The order is: 1) current the bizarre factor; 2) current the nice factor. Then the animal eats, drinks, experiences, or performs with the nice factor. Over time, this transfers the animal’s respondent behaviors and good emotions in regards to the great point to the previously bizarre factor.

We name the initially bizarre factor the conditioned stimulus. The nice factor is often an unconditioned stimulus: one thing the animal doesn’t must study to take pleasure in or want. Right here’s a extra in-depth have a look at what classical conditioning is and isn’t.

Since there are solely two issues to do—expose them to the bizarre factor, then give them the nice factor—it looks as if classical conditioning can be lifeless simple. However there are various issues that may go unsuitable, and certainly one of them is overshadowing.

A tan dog with a black muzzle and black on her ears is lying down on a sidewalk. She is wearing a pink harness and is on leash. Her mouth is open and she looks happy.
Clara is completely happy and relaxed throughout counterconditioning on the mall

Overshadowing is probably going when you’ve got a stimulus with a couple of side, akin to a lightweight and a sound collectively. That is known as a compound stimulus, and so they occur in the actual world lots. When the person stimuli get conditioned concurrently, whichever stimulus is stronger and extra noticeable to the animal will probably be conditioned extra strongly. It’s stated that this stimulus is extra salient. Extra of the good things from the nice factor will switch to it. The opposite stimulus will get a lot much less conditioning. Experiments have been carried out, for example, with a dim mild and a loud noise that happen concurrently (Kehoe, 1982; Moore, 2012, p. 204–205). They’re conditioned collectively, then examined individually. On this case, the noise will seemingly be robustly conditioned. However the mild may have little or no conditioning. You could possibly reverse the experiment with a vivid mild and a quiet noise, and the outcomes can be the other (though each examples would fluctuate by species).

The overshadowed stimulus doesn’t go completely unnoticed; it merely doesn’t grow to be an efficient conditioned stimulus.

Probability, 2003, p. 84

How is that this related to our real-world coaching? Most of us will not be making an attempt to situation a sound and a lightweight on the identical time. Extra seemingly, we’re engaged on a single factor like a muzzle, a noise, or the sight of one other canine. However unintended compound stimuli occur on a regular basis. As one textbook factors out, it’s virtually unimaginable to keep away from them (Pierce & Cheney, 2008, p. 58).

There are all the time many issues occurring within the setting, and our animals are consistently making an attempt to determine what the perfect predictors of fine (and unhealthy) stuff are.

The rationale that is necessary is that typically the stronger conditioning will connect to one thing we don’t intend, as a substitute of the factor we wish.

Pavlov found overshadowing very early on, and was the one who named it. Right here’s what he stated:

When the stimuli making up the compound act upon totally different analyzers, the impact of certainly one of them when examined singly was discovered very generally to overshadow the impact of the others virtually fully, and this independently of the variety of reinforcements to the compound stimulus.

Pavlov, 1927, p. 141

Different scientists have identified that even when a stimulus is the weaker certainly one of a compound stimulus, it could possibly work advantageous as a person stimulus.

…if two stimuli are introduced collectively as a compound DS, then one could dominate or overshadow the opposite, despite the fact that each CSs can be completely efficient in the event that they had been introduced alone.

Schwartz et al, 1995, p 59

It’s necessary to needless to say overshadowing applies to 2 conditioned stimuli being concurrently conditioned by the identical factor.

Why Do We Have to Find out about Overshadowing (And Some Different Stuff)?

We have to perceive overshadowing so we are able to carry out the clearest, cleanest, most profitable coaching we are able to. Classical conditioning, advert hoc counterconditioning, and desensitization and counterconditioning are simple to explain however the satan is within the particulars. Timing is essential, and it’s a unending wrestle to get the conditioned stimulus to be completely salient to the animal. Coaching in the actual world, exterior of the laboratory, means we are able to’t fully management the setting. As an illustration, I guess you’ve got at the least one mild swap in your home that clicks whenever you flip it on.

Overshadowing isn’t the one potential drawback.

To carry out clear and efficient classical conditioning:

• Make certain you additionally perceive how one can keep away from blocking and reverse conditioning.
• Make certain you understand how and why to do extinction trials.
• Know the distinction between delay and hint conditioning.
• Be sure you perceive the significance of the depth of the unconditioned stimulus.
• Make certain you recognize why the primary few exposures get you probably the most bang in your buck.
• Study in regards to the optimum time between trials (longer than you suppose!).
• Study in regards to the shock issue and how one can make use of it. There’s sturdy proof that the extra surprising the look of the unconditioned stimulus is, the stronger the conditioning have an effect on (Rescorla & Wagner, 1972). Nothing cleans up one’s classical conditioning act higher than determining how one can take away all of the “tells” that one thing fabulous goes to materialize.

These will not be simply theoretical considerations. They’re ideas and practices that apply on to actual life coaching and might make your coaching the perfect it may be.

When you’ve got been studying the weblog and watching my movies for some time, it’s possible you’ll say, “However you haven’t adopted all these items!” That’s proper! I’m all the time studying. I plan to get some higher movies up quickly.

Actual-Life Examples of Overshadowing

Listed here are some sensible examples of overshadowing in canine coaching due to a compound stimulus.

1. An auditory marker plus a hand reaching for meals. Clickers and different markers are classically conditioned to foretell a reinforcer, often meals. However if you happen to all the time attain in your deal with bag on the identical time you employ your marker, you’ve got a compound stimulus. Each are conditioned stimuli; your canine wasn’t born understanding the importance of your hand motion or the sound of your marker. One stimulus, the marker, is often auditory. The opposite is visible. One will overshadow the opposite and be extra salient to the canine. In case your canine consistently stares at your deal with hand, you recognize which one which is likely to be. Lewis was completely happy to oblige me by gazing my hand and pocket so I may take the picture above.

Reaching towards your deal with bag or pocket can overshadow the sound of your marker and will trigger its conditioning to be weak.  

Closeup of a leather dog collar with a bronze buckle and a group of metal tags attached.

2. A all of a sudden seen canine plus jingling tags. Let’s say you might be serving to a reactive canine utilizing classical counterconditioning. You expose the canine to the sight and sound of a helper canine at a non-aversive depth and current one thing fabulous. You carry out trials of this at totally different occasions and areas, utilizing desensitization to step by step convey the helper canine nearer whereas staying within the educated canine’s consolation zone.

However what in case your helper canine has loudly jingling collar tags? You might have a compound stimulus: the visible look of the helper canine and the sound of the tags. If the canine you might be working with has imaginative and prescient issues, or your setup induced the looks of the canine to not be apparent, or your canine is delicate to sounds, the jingling tags could possibly be extra salient. What occurs in actual life when a canine seems with out jingling tags, the higher conditioned stimulus? That constructive affiliation you tried to construct up so fastidiously won’t be there. It bought overshadowed. When that sort of drawback happens, persons are apt guilty the conditioning itself or blame the canine.

3. Saying “Drop” and dropping treats on the identical time (protocol particular). Should you observe Chirag Patel’s technique of educating canines to drop an merchandise, there’s a hazard of overshadowing if you happen to aren’t cautious together with your timing. (I’m not saying this can be a flaw within the protocol; it’s only a useful instance of an error a coach would possibly make.) This technique has a robust classical conditioning part, despite the fact that it’s educating an operant conduct. Within the technique, you give a verbal cue, akin to “Drop,” and observe it by dropping a handful of meals. You do that first when there’s nothing already within the canine’s mouth. The canine learns that the verbal cue predicts meals on the ground, and their subsequent operant conduct is often to open their mouths and strategy the meals. After you repeat that course of, if you happen to then say the cue whereas the canine has one thing of their mouth, they are going to typically open their mouth in anticipation of the meals. They drop the merchandise.

A hand is dropping a handful of pieces of white cheese

It’s a chic technique, and pretty foolproof. However what if you happen to stated “Drop” and all the time dropped the meals on the identical time? Dropping the meals may overshadow the verbal cue. The verbal cue would possibly merely be noise that occurs because the canine sees the meals. Then, if later you determined to wash up your approach and stated “Drop,” then paused earlier than dropping the meals, the canine would wait till you dropped the meals to let go of no matter was of their mouth. Which means your cue wouldn’t work in an emergency whenever you didn’t have treats with you. Whereas if you happen to do the protocol with the suitable timing and observe the opposite steps, it would work even when you’ve got no meals with you.

Utility to Operant Conditioning

For some motive, most articles on overshadowing I’ve learn by canine trainers use operant examples. They’re describing compound discriminative stimuli (cues) somewhat than compound conditioned stimuli used as conditioned reinforcers. (Whew!) There’s a sturdy relationship between these two. Cues could be increased order conditioned stimuli, and conditioned reinforcers present details about conduct. The distinction is often the function the stimulus performs in a coaching plan.

However in conduct evaluation, the time period overshadowing is used extra when referring to first order classical conditioning. Out of eight textbooks, I discovered just one operant instance (Domjan, 2014, p. 217). I’ve discovered some psychology articles that apply the time period to operant protocols, although.

Right here’s a paper about compound discriminative stimuli in operant protocols (Colwill & Rescorla, 1988). That is just like the examples within the canine trainers’ articles. The article doesn’t use the time period overshadowing (and the authors had been specialists on it). I’ll be completely happy to be corrected if overshadowing is used formally within the operant area although; maybe I haven’t discovered it but.

I feel I do know why operant examples of competing discriminative stimuli are often utilized in extra casual articles: examples are simpler to think about. Most of us have realized at occasions {that a} canine is following our hand sign and never the verbal cue we thought we had been educating. Although classical overshadowing can occur to us, it’s maybe much less widespread or much less dramatic.

When Overshadowing Doesn’t Occur

There’s all the time an exception. When coping with conditioned meals aversion, there are particular stimuli that intensify different stimuli somewhat than overshadowing them. That is known as the potentiation impact (Bouton, 2007, p. 216–217). However most of us are by no means going to run into this.

What Is Overshadowing Not?

An article is being handed round within the coaching world that makes use of the time period “overshadowing” to check with conflicted emotional responses in horses as a result of defective coaching. The writer defines overshadowing as “…the meals reinforcer and related conduct are masking the animal’s true emotions and conduct round a stimulus.”

This idiosyncratic use of the time period can do nothing however trigger confusion. Overshadowing is a phenomenon with an infinite quantity of analysis behind it and has been within the vocabulary of scientists and educated trainers for nearly 100 years. Utilizing it as a substitute to check with coaching errors that trigger a horse or different animal to finish up scared as a substitute of comfy can solely muddy the waters.

Paradoxically, understanding what overshadowing and the opposite phrases I point out above imply may assist handle the problems described within the article.


Bouton, M. E. (2007). Studying and conduct: A up to date synthesis. Sinauer Associates.

Probability, P. (2003). Studying and Habits. Toronto: Thomson-Wadsworth. p 84

Colwill, R. M., & Rescorla, R. A. (1988). Associations between the discriminative stimulus and the reinforcer in instrumental studying. Journal of Experimental Psychology: Animal Habits Processes14(2), 155.

Domjan, M. P. (2014). The ideas of studying and conduct. Cengage Studying.

Kehoe, E. J. (1982). Overshadowing and summation in compound stimulus conditioning of the rabbit’s nictitating membrane response. Journal of Experimental Psychology: Animal Habits Processes, 8(4), 313.

Moore, J. W. (Ed.). (2012). A neuroscientist’s information to classical conditioning. Springer Science & Enterprise Media.

Pavlov, I.P. (1927) Conditioned Reflexes: An Investigation of the Physiological Exercise of the Cerebral Cortex. Translated and Edited by G. V. Anrep. Oxford College Press, London. Will be accessed right here.

Pierce, W. D., & Cheney, C. D. (2008). Habits evaluation and studying (4th ed.). Psychology Press.

Rescorla, R.A., & Wagner, A.R. (1972) A principle of Pavlovian conditioning: Variations within the effectiveness of reinforcement and nonreinforcement. In: Classical Conditioning II: Present Analysis and Concept (Eds Black, A.H., & Prokasy, W.F.) New York: Appleton Century Crofts, 64-99.

Schwartz, B., Wasserman, E. A., & Robbins, S. J. (1995). Psychology of studying and conduct. New York: W. W. Norton & Firm.

Copyright 2023 Eileen Anderson


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