Aversive Tools: Side Effects on Dogs and Safer Options
Aversive tools, such as prong collars, shock collars and other devices that work by causing discomfort, pain or fear, can cause more than a sore neck. Research links them to higher stress, a gloomier outlook, fear-driven behaviour and, in some dogs, more aggression. Singapore’s own regulator now discourages shock and prong collars, and says reward-based training can work just as well or better.
This guide explains the side effects in plain language, shows what the evidence does and does not say, and helps you spot a trainer who will get results without them. If your dog already wears one of these tools, you will also find calm next steps.
TL;DR
Aversive tools suppress behaviour through discomfort or fear. They do not teach your dog what to do instead.
Studies link aversive methods to more stress signals, higher cortisol after training and a more “pessimistic” mood in dogs.
Physical risks include bruising, skin irritation and damage to the neck. Behavioural risks include fear, defensive behaviour and aggression.
Singapore’s AVS discourages shock and prong collars, and reward-based methods are at least as effective.
Ask any trainer to show you how they would teach the skill with rewards only. A good one will happily do so.
Table of Contents
What counts as an aversive tool
In training science, a method is aversive when it works because the dog wants to avoid something unpleasant. That can be a sharp pinch, an electric stimulus, a sudden jerk, a spray or a loud noise. The unpleasant thing is either added after a behaviour (positive punishment) or kept on until the dog complies (negative reinforcement).
Common examples you will see in Singapore pet shops and online:
Prong or pinch collars, with metal points that press into the neck.
Electronic (shock) collars, which deliver a stimulus by remote or on a boundary system.
Choke or slip chains that tighten when the dog pulls.
Spray, rattle or noise deterrents used to startle a dog.
Heavy leash corrections, which need no equipment at all but are still aversive.
The last item matters. Aversive does not only mean gadgets. A trainer who relies on leash pops, intimidation or physical pressure is using the same learning mechanism, just without a product you can buy.
The physical side effects
The neck is a crowded, delicate area, housing the trachea, thyroid, major blood vessels and nerves. One guide on aversive techniques notes that prong collars can cause bruising, skin irritation and damage to the neck and trachea. We have left that out of our sources because we could not verify the page it came from, so for the physical risks please rely on the official advisory below.
Singapore’s Animal & Veterinary Service (AVS) and the SPCA developed an advisory on aversive dog training devices through the Dog Training Standards Workgroup, which includes trainers, vets and animal welfare groups. It sets out the risks of electronic shock and prong collars and encourages the Least Intrusive, Minimally Aversive (LIMA) approach.
For a deeper look at one popular tool, see our page on prong collar risks and safer options.
There is also a risk to you. The Canadian Veterinary Medical Association’s position is that aversive techniques can increase the chance of a fear-based aggressive response and of injury to the handler. A dog pushed past its limit may bite the nearest person, not the thing that scared it.
The behavioural and emotional side effects
These are the effects owners miss, because they do not show up on the day you buy the collar.
Suppression, not learning
An aversive tool can stop a behaviour fast. Your dog stops barking at the gate, so it looks like it worked. But the dog has learnt only that barking hurts, not what to do instead. The fear or frustration underneath is still there.
Researchers made this point in a study of dogs’ moods: aversive methods may inhibit behaviour in the context where the punishment is applied, without changing the underlying emotional state. The dog is quiet, but not calm.
Stress that you can measure
A 2020 study in PLOS One followed 92 companion dogs from seven training schools, including 28 in a high-aversive group. Compared with dogs trained with rewards, the high-aversive dogs:
showed more stress-related behaviours such as lip licking and yawning,
spent more time in tense and low behavioural states,
panted more during training,
and had higher cortisol levels after training.
This was a study of association in real training schools, not a lab experiment on one tool. Even so, the pattern is consistent and the sample is meaningful.
A more pessimistic outlook
A 2021 study in Scientific Reports tested 100 dogs using a cognitive bias task. Dogs whose owners used two or more aversive methods were slower to approach ambiguous locations than dogs trained with rewards only. The researchers read this as a more negative underlying mood. In everyday terms, these dogs were less likely to expect that an unclear situation would turn out well.
Fear, defensive behaviour and aggression
The same welfare review that appears in the PLOS One paper is summarised on PubMed Central, where the authors note that aversive training has been strongly criticised on welfare grounds. Veterinary behaviour guidance, as quoted in a Beezys Rescue guide to choosing a dog professional, warns of fallout such as increased fear, anxiety and aggression, especially when aversives are used early or as a default.
This matters most for the dogs people reach for these tools with: reactive, fearful and aggressive dogs. A shock or a pinch delivered while your dog is staring at another dog can teach it that other dogs predict pain. The result is often a dog that is more reactive, not less.
Damaged trust and a tool the dog fears
Dogs also form associations with the equipment and the handler. A collar that predicts discomfort can become something your dog dreads. You may notice a dog that flinches when the lead comes out, avoids you at walk time or shuts down in the street. Those are welfare costs even if the barking has stopped.
What the experts and regulators say
This is not a fringe view. The guidance is consistent across bodies:
Body | Position |
Singapore AVS and SPCA (July 2025) | Discourages shock and prong collars; reward-based training can be just as effective or more so, with fewer welfare risks |
AVS guidelines for trainers | Techniques should be science-based, focused on reinforcing desirable behaviour and removing what maintains unwanted behaviour |
American Veterinary Society of Animal Behavior | No evidence that aversive practices are necessary; reward-based training offers the most advantages and least harm |
Canadian Veterinary Medical Association | Supports humane, science-based methods; reward-based methods are highly recommended |
On the legal side in Singapore, owning a shock collar and using it safely are different questions. We cover that in Singapore shock collars: legal to own, risky to use.
“But it worked on my friend’s dog”
This is the most common objection, and it deserves a fair answer.
Aversives can produce quick, visible change. That is exactly why they stay popular. If the dog stops pulling in two minutes, you see the benefit now and cannot see the cost later. Some dogs are tough and bounce back. Others are quietly more anxious, and nobody connects the two.
Three questions help you judge any “success story”:
Did the dog learn a skill, or just stop a behaviour? Walking nicely on a loose lead is a skill. Not lunging because lunging hurts is suppression.
Does it work without the tool? If the behaviour comes back the day the collar comes off, the dog learnt about the collar, not the behaviour.
How does the dog look afterwards? Loose, curious and happy to engage is a good sign. Hunched, still, lip-licking or avoiding people is not.
Signs your dog may be affected
Watch for these, particularly if you have used a prong, shock or choke collar, or heavy corrections:
Yawning, lip licking, panting or turning away during training
A dog who freezes, hides or refuses to move on walks
New fear of the lead, the collar, the garden or certain places
Growling or snapping that was not there before
Reluctance to try new things or to offer behaviours
Redirected behaviour toward you or another dog when startled
None of these proves a tool caused the problem. Fear, pain and medical issues can all produce the same signs. Experts say aggression and problem behaviour are often linked to pain, illness or fear, so a vet check is the right first step before any training plan. If your dog is growling, snapping or biting, book a vet visit and talk to a qualified behaviourist rather than trying to fix it alone with equipment.
What to do instead
Reward-based training does not mean being permissive. It means being clear about what you want, and paying your dog for doing it. The practical building blocks are:
Manage the environment. Use gates, leads, distance and routines so your dog cannot rehearse the unwanted behaviour. Every rehearsal makes it stronger.
Teach the replacement behaviour. If you do not want jumping, teach sitting for greetings. If you do not want pulling, reward position beside you.
Mark and reward. A marker word or click tells your dog exactly which moment earned the treat. Consistency matters more than intensity.
Work below threshold. Start at a distance where your dog can still think, then close the gap slowly.
Keep sessions short and happy. Five good minutes beat thirty frustrating ones.
Our guides on types of humane dog training methods and why humane training works better go through each method in more detail. For a general overview, try our guide to effective dog training techniques.
If your dog is reactive or aggressive
This is where owners are most tempted by aversives, and where the risk is highest. The better route is to understand the trigger and manage distance. Our guides on aggressive dog threshold management, aggression management techniques and aggression toward other dogs show how that works. If the aggression is aimed at you or your family, read our owner plan to reduce dog aggression in 8 to 12 weeks and get a professional involved early.
How to choose a trainer who does not use aversives
Labels can mislead. A guide from Beezys Rescue points out that words like “balanced” or “results-oriented” are often code for aversive methods. Instead, look for a trainer who:
teaches alternative skills rather than only stopping behaviours,
changes the setup so the dog cannot practise the problem,
will demonstrate a skill using positive reinforcement only, in an observation session,
explains in plain words what will happen if the plan does not work, without reaching for a tool.
In Singapore, you can also check for accreditation. AVS launched the AVS-Accredited Certified Dog Trainer (ACDT) scheme on 10 December 2022 as a benchmark of competency in managing dog aggression and other issues effectively and humanely.
Red flags
Guarantees of instant results
Refusal to let you watch a session
“Your dog is dominant” or “stubborn” as the main explanation
Selling a collar as the first answer
Blaming the dog when something does not work
Our perspective
We have trained dogs in Singapore for over 20 years, and the pattern we see is steady. Most owners who arrive asking about prong or shock collars are not cruel. They are tired, worried and have been told it is the only way. Usually the dog is scared, under-exercised or has never been shown what is wanted.
We use humane, science-based methods only, and our trainer is certified and AVS-accredited. That does not make our work soft. Reward-based training asks more of the owner at first: more patience, better timing, more planning. In return, you get a dog that wants to work with you, and that is a better foundation for a calm, confident home.
We also believe the work should not end when the classes do. Every client receives free lifetime support, because a new routine is hardest to keep up when real life gets busy.
— Mark
How we can help
If you want to stop using an aversive tool, or never start, we can build a plan around your dog and your home.
Private Obedience Dog Training Classes: 200 $ per class, for lead manners, recall and everyday skills.
Reactive Dog Classes: 200 $ per class, for dogs that lunge or bark at other dogs.
Aggressive Behaviour Consult: 200-250 $ per session, to understand the cause and plan the next steps.
Board & Train: from 700 $ per week, when you want focused training with ongoing owner support.
See all options on our prices and classes page, or visit Happy-Dog Training to get in touch.
FAQ
Do vets recommend shock collars?
Generally, no. Veterinary behaviourists say there is no evidence that aversive practices are necessary for training. In Singapore, AVS and the SPCA’s advisory discourages shock and prong collars. If you are unsure about your dog, ask your own vet.
Are prong collars worse than flat collars or harnesses?
They carry more risk, because they work by pressing on the neck to cause discomfort. AVS has specifically advised against them. A well-fitted harness or flat collar, combined with teaching your dog to walk beside you, avoids those risks.
Will my dog be damaged for life if I used an aversive tool?
Not necessarily. The research shows associations with stress and a gloomier outlook, not a fixed outcome. Stop using the tool, have a vet check your dog, and begin reward-based training. Most dogs respond well to a calmer, more predictable routine, but a dog with fear or aggression needs a qualified behaviourist.
What can I use instead of aversive tools for a dog that pulls?
Teach loose-lead walking by rewarding your dog for staying beside you, and stop moving forward when the lead goes tight. Short, frequent practice in quiet places works better than long walks full of distractions. A trainer can help with a harness or head halter introduced gently with treats.
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