When Training Creates Fear or Anxiety:The Hidden Cost of Shock Collars

I rarely post about controversial topics like this because I prefer to spend my time and energy sharing science-based methods that work rather than focusing on what doesn’t. However, after a recent rash of calls from people whose dogs developed aggression and other significant behavior concerns after using shock collars, I felt it was time to share this information.

It’s 2026, and we have more access to science-based information about dogs than ever before.

Yet shock collars—also called e-collars, remote collars, training collars, and sometimes marketed as “stimulation” or “tens units”—are still being recommended and used.

There are decades of research showing the potential fallout from aversive training methods, including increased fear, anxiety, stress, avoidance, unpredictable behavior, welfare concerns, and, in some cases, even aggression.

And here’s the part I really want you to understand:

The concern isn’t simply whether a shock hurts in that moment. The concern is what repeated experiences of tools that use fear, pain, and stress can teach a dog’s brain about the world.

It’s Not a “Tap on the Shoulder”

And NO—calling it an “e-collar,” “stimulation,” a “tap,” or comparing it to a TENS unit doesn’t change what the dog experiences. It is an aversive stimulus delivered through an electronic collar. The terminology is often a marketing ploy making the tool sound gentler than it actually is.  What matters is the dog’s experience and the science—not what we choose to call it.

Let’s Think About How Dogs Learn

Dogs are associative learners.

They constantly make connections between things in their environment:

     Leash = walk

     Cabinet = treats

     Doorbell = someone is coming

So, what does a shock, beep, or vibration mean to the dog?

The person using the collar may intend for the dog to associate the correction with barking, jumping, chasing, or running away.  But dogs don’t always make the association we intended.

A dog could instead associate the unpleasant event with:

• • the stranger approaching
  • another dog
  • a child
  • a particular location
  • the person holding the leash
  • the sound of a doorbell
  • something else happening in the environment

And suddenly, the thing we were trying to correct isn’t the thing the dog is worried about.

Fear Changes How the Brain Processes the World

Think of a dog’s brain as having a smoke detector or alarm.

When a dog experiences something frightening or painful, the nervous system can interpret it as a threat.

Threat → stress response → survival mode

When the brain is focused on safety, learning, exploration, and thinking can become harder.

Repeated stressful experiences can also influence how the brain processes future experiences too.

This is where emotional learning becomes important.

Emotional learning and memories are especially important to survival. The brain doesn’t want us to forget experiences that could have been dangerous. Remember where you were at 9/11, or remember a car accident or maybe a traumatic experience as a child? That’s emotional learning. That’s why a single frightening event can sometimes have a lasting impact—and why repeated experiences can be particularly concerning.

The goal of humane training isn’t simply to make a dog stop doing something.

The goal is to teach the dog what we want while keeping the dog emotionally safe enough to learn.

What Can the Fallout of These Tools Look Like?

Per research aversive training can potentially contribute to:

• • increased fear and anxiety
  • increased stress and stress hormones such as cortisol
  • avoidance and withdrawal
  • negative associations
  • increased vigilance or sensitivity to the environment
  • reduced willingness to interact or explore
  • suppression of behavior rather than true learning
  • damaged trust and relationships
  • and, in some dogs, defensive or aggressive behavior

Suppression is an important distinction.  A dog may stop barking because it is afraid of what will happen if it barks.

That’s not necessarily the same thing as learning that barking isn’t necessary. The behavior may be suppressed while the underlying emotion remains—or even becomes worse.

What About Vibrate?

This is another important question: “What if I only use the vibrate setting?”

Vibration is not the same physical sensation as electrical stimulation, but that doesn’t automatically make it harmless.  Dogs learn through associations. If a vibration consistently predicts something unpleasant, frightening, or startling, the vibration itself can become part of the dog’s emotional learning history.

The important question isn’t simply: “Does it hurt?”

The question is: “What is my dog learning and feeling when this happens?”

“But My Dog Stopped Doing It!”

I hear this all the time.  Someone tells me: “The collar worked! My dog stopped chasing.”

Or: “It stopped the barking.” The behavior may indeed stop but often what is left in its place is an overactive alarm setting – anxiety!   Also stopping a behavior doesn’t mean the we have addressed the emotion underneath it so the behavior often returns!

For every story about a dog whose behavior stopped after an aversive tool was introduced, I can share many stories from dogs who developed increased fear, anxiety, stress, avoidance, aggression or other behavioral fallout.

And because I work with dogs experiencing these problems, I see the other side of the story. I look forward to the day when my phone doesn’t ring because a dog has developed behavior problems after being trained with an aversive tool.

“But My Trainer Says It’s Safe.”

Your coworker may recommend it.  Your friend may  use it. A person calling themselves a trainer may tell you that it is necessary.

Please do your homework.

Look at the actual research—not just someone’s one experience.

We have access to more science-based information about canine behavior than ever before. Many peer-reviewed studies are available online, including research that is open access and available for anyone to read.

Our understanding of animal behavior has changed dramatically over the years and many training practices that were considered acceptable decades ago are no longer considered appropriate as our understanding of animal welfare and learning has evolved.

What Does the Research Say?

One particularly useful peer-reviewed study is:

Vieira de Castro et al. (2020), “Does training method matter? Evidence for the negative impact of aversive-based methods on companion dog welfare,” PLOS ONE.

Researchers studied 92 companion dogs and compared dogs trained primarily with reward-based methods with dogs trained using aversive methods.

Dogs exposed to higher levels of aversive training:

• • showed more stress-related behaviors
  • spent more time tense
  • panted more
  • had larger increases in cortisol after training
  • and showed more pessimistic responses on a cognitive-bias test

That last finding is particularly interesting.  A cognitive-bias test essentially asks:

“Does this dog expect something good to happen—or something less favorable?”

Dogs exposed to more aversive training were more likely to respond as though they expected the less favorable outcome. This provides evidence that aversive training can negatively affect a dog’s emotional state and expectations of the world thus impacting their stress level and behavior!

Read the full peer-reviewed study — PLOS ONE  https://pmc.ncbi.nlm.nih.gov/articles/PMC7743949/

 Research Specifically on E-Collars

There is also research specifically examining remote electronic collars.

A 2014 peer-reviewed study by Cooper et al. compared dogs trained with e-collars with dogs trained using reward-based methods. Even when experienced e-collar trainers used relatively low settings and a warning signal, dogs in the e-collar group spent more time tense, yawned more, and interacted less with their environment.

The researchers found no consistent training benefit from the e-collar and greater welfare concerns compared with reward-based training.

Read the e-collar study — PLOS ONE:  https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0102722

What About E-Fences?

Electronic fences deserve their own conversation.   A dog doesn’t understand:

“I crossed an invisible property boundary, so now I receive an appropriate consequence.”

The dog experiences an event.  And because dogs are associative learners, the dog may make associations with whatever is happening around them when that event occurs.

If you’re considering an electronic fence, please research the behavioral fallout associated with electronic fencing before making your decision.

The American Veterinary Society of Animal Behavior (AVSAB) is an excellent place to start. AVSAB includes veterinarians and behavior professionals dedicated to advancing evidence-based approaches to animal behavior.

 “What If I Only Use It Occasionally?”

Even an occasional aversive event becomes part of a dog’s learning history.

And we know that emotionally significant experiences can stick with us – like glue!

Think about your own life.

Do you remember where you were when you heard about September 11?

Do you remember the beginning of the COVID-19 pandemic?

We don’t remember every ordinary Tuesday.

But emotionally significant events can be different.

Dogs have emotional learning too.

Don’t assume that because something happened only once, it had no impact.

Your Dog’s Life Is Short

Your dog gets only a relatively short time to share their world with you.

They already have to navigate a human world filled with rules, expectations, noises, strange objects, unfamiliar people, other animals, and situations they don’t naturally understand.

We have the ability to teach them without adding fear and pain to that equation.

We can teach without intimidation.

We can teach without pain.

We can teach without fear.

We can teach without causing anxiety.

And we can teach in ways that build trust, confidence, communication, and a stronger relationship between dogs and their people.

So please—

Do your research.

Question outdated training advice.

Look at what the science says.

And most importantly:

Please teach with kindness.

Your dog’s life is short.

Make the time you have together humane, safe, and worth remembering.