Habituation and Sensitization in Dogs: When Repetition Helps

1. Two Opposite Answers to the Same Repetition

1.1 What Happens When Something Keeps Happening

A dog hears the neighbor's door for the hundredth time. It can respond in one of two directions: less each time, or more each time. The first is habituation, the second sensitization, and both can follow from repeated exposure to a stimulus.

Which one occurs is not random, and it is not a property of the dog alone. It depends on several factors, including stimulus intensity, previous experience, context, and the dog's current state.

1.2 Why This Is the Most Underrated Mechanism in Training

Habituation is the simplest form of learning there is. It requires no reward, no pairing, no cue and no plan. It is also the mechanism behind the single most common piece of everyday advice: he'll get used to it. Sometimes that is true. Sometimes the repetition is making things worse, and the advice is the reason a problem became entrenched.

1.3 How to Read the Evidence

The characteristics of habituation are established across species, from invertebrates to humans, and were formally revised by a group of researchers in 2009. Canine-specific experimental work on habituation as such is sparse; what exists in dogs concerns noise fears, kennel environments and repeated stimulus exposure. This article states which is which (why the source of a claim matters).

1.4 Where the Terms Come From

Both concepts predate modern dog training by decades. They were developed in neurophysiology, where the question was how a nervous system stops responding to something that keeps happening without consequence, and they have been studied in organisms from sea slugs to humans. That breadth is the reason the framework is trusted; it is also the reason it has to be applied to dogs with care.

The terms entered dog training through behavior therapy, where they sit alongside classical and operant conditioning as the non-associative forms of learning: no pairing, no consequence, just exposure.

1.5 Why "Non-Associative" Matters

In classical conditioning, a stimulus comes to predict something. In operant conditioning, a behavior comes to produce something. Habituation involves neither: the stimulus predicts nothing and the dog's behavior changes nothing about it. That is precisely why it is both cheap and unreliable — nothing is being built, only a response fading (how consequences shape behavior).

1.6 What the Distinction Buys a Trainer

Most training vocabulary describes what a person does. Habituation and sensitization describe what happens to the dog whether or not anyone intends it. That makes them useful for explaining outcomes nobody planned: the walk route that has slowly become a problem, the sound the dog stopped noticing, the visitor routine that gets worse each week.

They also give a criterion that is independent of method. Whatever the plan, if responses are growing across sessions it is the wrong plan for this dog at this intensity.

2. Habituation

2.1 The Definition

Habituation is a response decrement resulting from repeated stimulation, which is not due to sensory adaptation or motor fatigue. The dog has not stopped hearing the sound and its muscles are not tired; the response to that particular stimulus has decreased because the stimulus has proved to be without consequence.

2.2 The Characteristics

A workshop of researchers published a revised description of the behavioral characteristics of habituation, updating the classic list from the 1960s (Rankin et al., 2009; Thompson & Spencer, 1966). Several of them have direct practical implications.

Repetition produces a progressive decrease in response. The decrease is typically rapid at first and then flattens.

Spontaneous recovery. If the stimulus stops being presented, the response comes back over time.

Potentiation of habituation. After repeated series of habituation and spontaneous recovery, the decrement becomes successively more rapid or more pronounced (Rankin et al., 2009).

Frequency effects. More frequent stimulation produces a more rapid or more pronounced decrement — and also more rapid spontaneous recovery once the decrement has reached its floor (Rankin et al., 2009).

Intensity effects. Weaker stimuli habituate faster. Strong stimuli may produce no observable habituation at all.

Stimulus specificity. Habituation to one stimulus does not automatically transfer to a different one.

Dishabituation. Presenting a different stimulus restores the decremented response to the original one (Rankin et al., 2009).

2.3 The Practical Translation

Four of those points do most of the work in practice. Quiet versions habituate, loud ones may not. Gaps undo progress. Similar is not the same. And one unrelated shock can bring the old response back.

2.4 What It Is Not

A decrease in responding is only habituation if two alternatives are excluded. Sensory adaptation means the receptors themselves have become less responsive — the eye adjusting to light. Fatigue means the animal cannot produce the response any more. Habituation is a change in the nervous system's processing of that particular stimulus, which is why a dog that has stopped reacting to a sound will still react to a different one at the same volume.

That distinction has a practical version. A dog that has stopped responding because it is exhausted has not habituated, and the response will be back tomorrow.

2.5 Short-Term and Long-Term

Habituation within a session and habituation across sessions behave differently. Rapid repetition produces a fast decrement that also recovers quickly; more widely spaced exposures produce slower learning that lasts longer (Rankin et al., 2009). That is the same spacing effect familiar from other kinds of learning, and it argues against the common approach of doing everything in one long session.

2.6 Habituation Is Not Indifference

A dog that no longer reacts to a stimulus has not decided it is unimportant in any deliberate sense, and it may still notice it. The response has decreased; the perception has not disappeared. That is worth remembering before concluding that a dog is "fine" with something because it no longer reacts visibly (why absent behavior is not an identified state).

2.7 Why the Decrement Flattens

The largest drop in responding usually comes early, and later repetitions add less. Households that judge progress by the difference between session nine and session ten will conclude that nothing is happening, when the mechanism predicts exactly that shape.

The useful comparison is therefore across weeks rather than across single sessions, and against a record rather than against an impression.

2.8 Context Matters More Than Expected

A response that has habituated in one place can return in another. Dogs that ignore traffic at home may react to it on holiday, and a dog that tolerates the clinic waiting room may not tolerate the same sounds in a corridor. Context-dependence is familiar from other forms of learning and applies here too (why transfer cannot be assumed).

For plans this means building exposure in the places where the behavior matters, not only where it is convenient.

3. Sensitization

3.1 The Opposite Outcome

Sensitization is an increase in responding to a repeated stimulus. It tends to occur with stimuli that are intense, aversive or arousing, and it can generalize more broadly than habituation does: a sensitized animal may respond more strongly to other stimuli as well.

3.2 Dual-Process Theory

The standard account holds that repetition engages two independent processes at once — one decreasing responding, one increasing it — and that what is observed is their sum (Groves & Thompson, 1970). That is why the same procedure can produce opposite results in two dogs, or in the same dog at two intensities.

3.3 What It Looks Like at Home

The dog that barks a little at the first delivery of the day and is frantic by the fourth. The dog whose reaction to other dogs grows across a walk rather than settling. The dog that copes with the first evening of fireworks and not the third. Each is the sum of the two processes coming out on the wrong side.

3.4 Why Fear Cases Trend Toward Sensitization

Fear-inducing stimuli are by definition intense for that individual, which is exactly the condition under which the incrementing process dominates. That is the mechanical reason why "expose him until he gets over it" fails so reliably in fearful dogs (how fear responses are established).

3.5 Sensitization Generalizes More Readily

Habituation is tied to the specific stimulus; sensitization tends to spread. A dog that has become sensitized to bangs may start reacting to doors, to the click of a lighter, and eventually to the situations in which bangs have occurred. That asymmetry is one reason fear problems grow while tolerance does not.

It also matches what is seen clinically in dogs whose fear has widened to whole environments rather than staying with the original trigger (how noise fears develop).

3.6 Arousal Carries Over

Sensitization is not purely about the stimulus. An animal that is already aroused responds more strongly to the next thing, whatever it is. In practice that means a walk can go wrong cumulatively: the first encounter raises the baseline, the second starts from there, and by the fourth the dog is reacting to things it would normally ignore (how reactive episodes build).

3.7 Why Some Dogs Sensitize More Easily

Threshold differences between individuals mean that the same stimulus is mild for one dog and overwhelming for another. Temperament, previous experience, pain and current state all shift where that line sits, which is why a group exercise that habituates most of a class can sensitize one dog in it (how individual differences are described).

3.8 Sensitization Is Not a Character Flaw

A dog whose reactions grow across repeated exposures is often described as stubborn, dramatic or badly trained. Its response can be explained by its learning history and its current load; the household's schedule can be an important factor in that. That reframing matters because it changes the response from pressure to a change of plan.

It also protects dogs from escalating interventions: a plan that is sensitizing a dog will not be fixed by making the exposure more intense or by correcting the reaction (what punishment adds to the picture).

4. The Line Between Them

4.1 Intensity Decides

The single most useful variable is how strong the stimulus is for this dog in this moment. Stimulus intensity is one important factor: lower-intensity exposures are more compatible with habituation, while intense or aversive exposures increase the risk of sensitization. The relationship is not a simple fixed threshold rule, because context and internal state also influence the response.

That threshold is individual, changes with context, and can be influenced by factors such as pain, arousal, fatigue and unfamiliar situations (how arousal shifts thresholds).

4.2 Why "He'll Get Used to It" Is a Coin Toss

Said about a puppy meeting a vacuum cleaner from across the room, the advice describes habituation and is usually right. Said about a dog that panics at the vacuum cleaner, it describes a procedure that will sensitize, and it is usually wrong.

The words are identical; the prediction depends entirely on whether the dog is under or over its threshold.

4.3 The Observable Test

Watching across repetitions answers the question directly: is the response getting smaller, or larger? A dog whose reactions decrease across several repetitions shows a pattern consistent with habituation. A dog whose reactions increase shows a pattern consistent with sensitization, and the intensity or the procedure should then be adjusted.

4.4 The Threshold Is Not a Fixed Number

A dog that copes with a passing cyclist at ten metres on a quiet morning may not cope with the same cyclist at twenty metres after a bad night, in an unfamiliar street, or when it is already worked up. Any plan that fixes distances in advance and follows them regardless will be below threshold on some days and above it on others.

The workable version is to set the criterion from the dog's behavior in the moment rather than from the plan on paper.

4.5 Pain Lowers Thresholds

A dog that is uncomfortable has less capacity to absorb anything, and stimuli that were previously tolerable can become triggers. Where a dog that used to habituate has started sensitizing instead, a medical explanation belongs on the list before the training plan is rewritten (why pain is easy to miss).

4.6 Where the Threshold Can Be Seen

The observable version of "below threshold" is a dog that notices the stimulus — turns its head, pauses, flicks an ear — and then returns to what it was doing without help. Above threshold looks different: the dog stops what it was doing, orients fully, and either cannot re-engage or needs the handler to get it back.

That distinction takes no equipment and is reliable enough to run a plan on, which is why it is worth teaching households explicitly rather than giving them distances in metres.

4.7 Two Dogs, One Exercise

A class walks a line of dogs past a parked car with a person standing beside it. For most of them the person is mildly interesting and the third pass is unremarkable: habituation. For one dog the same person at the same distance is over threshold, and by the third pass it is lunging: sensitization. Nothing about the exercise changed; the threshold did.

That is the everyday reason group exercises need individual distances, and the reason a trainer's judgment about one dog does not transfer to the next.

5. Habituation Is Not Desensitization

5.1 The Difference

Habituation is a naturally occurring decrement in responding to a repeated, inconsequential stimulus. Systematic desensitization is a deliberate procedure: the stimulus is presented at an intensity below the response threshold and increased gradually, usually paired with something pleasant, which adds counterconditioning (how the procedure is run).

5.2 Why the Confusion Matters

Habituation has no built-in safeguard. A household that believes it is "desensitizing" the dog by walking past the barking dog every day is relying on habituation at an intensity that may be well above threshold — and the mechanism that is actually running is the other one.

Desensitization borrows the intensity rule from habituation and adds control over it. That control is the whole difference.

5.3 What Counterconditioning Adds

Habituation changes how much a dog responds. Counterconditioning changes what the stimulus predicts. In the survey data on firework fears, counterconditioning was the technique owners rated most effective, at over 70 percent, with relaxation training close behind at 69 percent and noise recordings at 55 percent (Riemer, 2020).

Those are owner ratings rather than measured outcomes, and the ordering is informative: the procedures that change meaning outperformed repeated exposure alone.

5.4 Flooding Is the Failure Mode

Exposing a dog to the full-intensity stimulus and preventing escape until the reaction subsides is sometimes described as letting the dog habituate. Mechanically it is the opposite: it is exposure far above threshold, and the quiet dog at the end of it may have stopped responding for reasons that have nothing to do with habituation (what passivity can mean).

The distinction is observable. Habituation looks like a dog that notices and goes back to what it was doing; the other thing looks like a dog that has stopped doing anything at all.

5.5 Which Mechanism Is Running

Three questions separate them in practice. Can the dog leave if it wants to? Is the intensity low enough that the dog notices without reacting fully? And is the response getting smaller across repetitions rather than just within one long session? Three yeses describe controlled exposure conditions that allow habituation or desensitization processes to occur; a no to the first two raises the risk that the dog is being overwhelmed rather than learning to cope.

5.6 Where Habituation Is Enough

For neutral, low-intensity, everyday stimuli — traffic noise from a new flat, the washing machine, the sound of the neighbors — habituation alone usually does the job, and adding food or ceremony is unnecessary. Reserving the structured procedures for stimuli that actually frighten the dog keeps the workload realistic.

5.7 Why the Confusion Is So Common

Both words describe a response getting smaller with exposure, and in ordinary speech "desensitize" is used for both. The consequence is not terminological: a household told to desensitize its dog to the postman, with no guidance on intensity, will do what is easiest, which is to keep letting it happen at full strength.

Saying the rule instead of the word solves most of it: keep it quiet enough, far enough away or short enough that your dog notices without reacting, and go from there.

5.8 One Word of Caution About Labels

Calling a plan "desensitization" does not make it one, and calling a dog's improvement "habituation" does not establish the mechanism. In an applied setting several processes usually run at once: some habituation, some counterconditioning through incidental good experiences, some extinction of behaviors that no longer work, and occasional sensitization on bad days.

The honest description of most successful exposure work is therefore a mixture. What matters for decisions is the direction of the response, not which label the mixture gets.

5.9 Management Is Part of the Plan

Between sessions, the dog usually meets the same stimulus at full strength: the neighbor's dog is still there, the fireworks still happen, the postman still comes. Those unplanned exposures are above threshold and work against everything the planned sessions achieve, which is why management — barriers, routes, timing, rooms — is not a lesser substitute for training but a condition for it.

6. Canine Evidence

6.1 Habituation in a Kennel

One of the clearest canine demonstrations comes from an unexpected source. In a crossover study of 50 kenneled dogs, classical music was associated with improved heart rate variability and more resting on the first day, but by the seventh day of music the measures resembled the first day of silence, with habituation apparent after as little as one day (Bowman, Dowell & Evans, 2015).

That is habituation in its textbook form: a stimulus without consequence, a rapid decrement, and a practical implication for anyone relying on a permanent playlist (what the auditory enrichment literature shows).

6.2 Recovery Between Sessions

In an experimental study of dogs exposed to a range of stimuli, heart rate returned to baseline within about eight minutes after acute stimuli (Beerda, Schilder, van Hooff, de Vries & Mol, 1998). Short-term recovery of that kind is the physiological counterpart of the spontaneous recovery described in the habituation literature, and it is why massed repetitions within a session behave differently from the same number spread across weeks.

6.3 Noise Fears Increase With Age

In a large survey of owner-reported fear of noises, risk increased with age, and early environment and exposure to specific loud noises were implicated in how these fears develop (Blackwell, Bradshaw & Casey, 2013).

Rising prevalence with age is consistent with accumulating sensitization across repeated exposures, and it is survey data: it cannot distinguish sensitization from other age-related processes.

6.4 What Is Missing

There is no body of canine experiments that systematically varies stimulus intensity and measures whether responding decreases or increases. The mechanism is taken from the general literature and applied to dogs, which is defensible and should be said out loud.

6.5 Puppies and Early Exposure

Much of what is called socialization is habituation to non-social stimuli: surfaces, vehicles, machines, sounds. The same rules apply, including the one most often broken — that intensity must stay below the threshold at which the puppy reacts fully, because above it the same outing produces the opposite of what was intended (how early development works).

Early environment and exposure to specific loud noises were among the factors implicated in how noise fears develop (Blackwell et al., 2013), which is consistent with both processes operating during that period.

6.6 Kennels, Clinics and Boarding

Environments that impose continuous stimulation give animals no control over intensity, which is the condition under which habituation cannot be relied on. The music finding shows the benign version — a stimulus that simply stopped having an effect (Bowman et al., 2015) — and the same setting can produce the other outcome for a dog that finds the environment frightening (why control over a stimulus matters).

6.7 Repeated Series and Faster Re-Learning

One characteristic is easy to overlook and encouraging for practice: after multiple series of repetitions and recoveries, the decrement becomes successively more rapid or more pronounced (Rankin et al., 2009). A dog that lost its progress over the winter should regain it faster in spring than it did the first time.

That reframes the return of an old response. It is not the work undone; it is the second pass through a process that gets quicker each time.

6.8 The Frequency Trade-Off

More frequent stimulation produces a faster decrement and also faster spontaneous recovery once the decrement has bottomed out (Rankin et al., 2009). Intensive exposure therefore buys quick results that are correspondingly fragile, while spacing produces slower gains that hold better.

For a household that means a realistic weekly rhythm beats a concentrated fortnight, which is the opposite of how most exposure plans are scheduled.

6.9 Extinction Is a Different Mechanism

Habituation and extinction both look like a response fading, and they are not the same. Extinction concerns a learned association or a reinforced behavior that stops paying; habituation concerns a response to a stimulus that never meant anything (what extinction does).

They share two properties that cause the same confusion in practice: both show spontaneous recovery after a break, and both can return in a new context.

6.10 Why the Music Finding Is a Good Model

The kennel study is worth dwelling on because it has everything the mechanism predicts in one place: a stimulus with no consequence attached, a clear effect at first exposure, a decrement across days, and a floor reached within a week (Bowman et al., 2015). It is also a reminder that habituation happens to interventions, not only to problems.

Anything a household sets up permanently — a sound machine, a calming spray, a particular routine before departures — is a candidate for the same fate. If it worked at first and no longer does, that may be the mechanism rather than a faulty product (how such effects are measured).

6.11 Age and Accumulated Exposure

Noise fears increase with age in survey data (Blackwell et al., 2013). One reading is accumulated sensitization: each bad experience adds to the last. Others are equally available — hearing changes, pain, cognitive change, or reporting effects — and a cross-sectional survey cannot separate them (what changes in aging dogs).

What follows for practice is unaffected: an older dog's growing reaction to noise deserves a look rather than resignation.

7. What Follows for Practice

7.1 Work Below Threshold

Distance, volume, duration and movement are the four dials. Reducing any of them lowers intensity, and the goal is a version of the stimulus the dog notices and can disengage from.

7.2 Expect Spontaneous Recovery

After a break — a holiday, an illness, a winter indoors — the old response returns. That is a property of the mechanism, not a sign that the work failed, and it usually comes back faster the second time (Rankin et al., 2009).

7.3 Do Not Expect Transfer

Habituation is stimulus-specific. A dog habituated to the neighbor's dog behind the fence has not habituated to dogs in general, and a dog that ignores the washing machine may react to the dishwasher.

7.4 Protect Against Dishabituation

An unrelated startling event can restore a response that had decreased (Rankin et al., 2009). Planning for that — a quieter week after a difficult incident, rather than pressing on — prevents the household from reading a normal property of the mechanism as a relapse.

7.5 Watch the Direction of Travel

Across every plan that relies on exposure, the measure that matters is whether responses are getting smaller or larger over sessions. Everything else is detail.

7.6 Three Situations

The dog that barks at the neighbor's dog through the fence. Daily exposure at full intensity, no escape, and a response that has grown over months. This is the classic sensitization case, and the first change is distance or a visual barrier rather than more practice.

The dog in a new flat near a tram line. A neutral, predictable, moderate stimulus with no consequence attached. Habituation usually handles this within weeks, provided nothing makes the tram meaningful — a startle at the wrong moment, or an owner reacting each time it passes.

The dog that was fine with the vacuum cleaner and is not any more. Something happened: a collision, a fright, a bad association, or pain that makes the noise less tolerable. This is dishabituation or new learning rather than a failure of the earlier habituation, and it needs the question of what changed.

7.7 A Two-Week Test

For any exposure-based plan, a simple record settles the direction: for each session, note the distance or volume, how the dog reacted on a three-point scale, and how long it took to go back to normal behavior. Two weeks of that shows whether the line is going down or up, which is the only thing the mechanism cares about.

7.8 What to Tell a Household

Four sentences cover it. Dogs get used to things that are quiet enough and harmless. The same thing at a level that frightens them makes it worse, not better. Progress fades after breaks and has to be topped up. And if the reactions are getting bigger rather than smaller, stop and reduce the intensity rather than pressing on.

7.9 What Not to Do

Do not run exposure sessions when the dog cannot leave, do not continue when reactions are growing, do not increase intensity because the last session went well, and do not treat a return after a break as evidence that the approach failed. Each of those follows directly from a documented property of the mechanism rather than from a training philosophy.

7.10 Pairing Exposure With Something Good

Where a stimulus already carries meaning for the dog, exposure alone is the weaker tool. Adding a consistent pleasant consequence changes what the stimulus predicts rather than only how much the dog responds, which is the reason counterconditioning outranked noise recordings in the owner ratings (Riemer, 2020).

The practical rule of thumb: neutral stimuli need only patience and low intensity; frightening stimuli need the meaning changed as well.

7.11 Setting Expectations

Households given a realistic picture in advance stop fewer plans early. Three points do most of that work: the biggest change usually comes first and then progress slows, a break will bring some of the response back, and one bad incident can undo several good weeks without meaning the work was wasted.

Framed that way, the setbacks become part of the description rather than evidence that the method or the dog has failed.

8. Summary at a Glance

Repetition can go either way — Habituation decreases responding, sensitization increases it, and both follow from the same input.

Intensity decides which — Weak stimuli habituate readily; strong ones may not habituate at all (Rankin et al., 2009).

Habituation is stimulus-specific — It does not automatically transfer to similar stimuli.

Breaks undo it — Spontaneous recovery is a defining feature, and re-habituation is usually faster (Rankin et al., 2009).

An unrelated event can reset it — Dishabituation restores the decremented response (Rankin et al., 2009).

Dogs habituated to music within a week — In a crossover study of 50 kenneled dogs (Bowman et al., 2015).

Counterconditioning outranked exposure alone — Over 70 percent versus 55 percent for noise recordings in owner ratings (Riemer, 2020).

8.1 Reading a Plan That Is Not Working

When an exposure-based plan stalls, the mechanism suggests four questions in order. Is the intensity above the dog's threshold today? Are the sessions massed rather than spaced? Has something reset the response — an incident, an illness, a change of place? And is the stimulus actually the same one, or a variant the dog has never habituated to?

Most stalled plans answer yes to one of those, and the fix follows from the answer rather than from more repetitions.

8.2 How the Pieces Fit Together

The general framework supplies the rules, the canine data supply examples rather than confirmation, and the clinical literature supplies the consequences of getting it wrong. That is an honest description of the evidence: a well-established mechanism, applied to dogs by analogy, with the applied field agreeing about what works but having tested the mechanism itself very little.

8.3 What a Household Should Record

Two weeks of four columns — date, intensity used, reaction on a three-point scale, and time to return to normal behavior — answers everything the mechanism needs. It also converts an argument about whether the dog is improving into a line that either falls or rises.

8.4 Where This Article Sits in the Library

Habituation and sensitization sit underneath several topics covered separately here. Desensitization borrows the intensity rule from habituation; extinction is its associative counterpart; fear conditioning describes what happens when a stimulus acquires meaning; and arousal determines where the threshold lies on a given day. Reading them together makes the common structure visible (how these mechanisms relate).

9. Research Gaps and Critical Appraisal

The framework is cross-species. The characteristics come from work across many organisms and have not been systematically verified in dogs (Rankin et al., 2009).

Thresholds are unquantified. No canine study defines the intensity at which repetition switches from decreasing to increasing responding.

Individual differences are unexamined. Which dogs habituate readily and which sensitize, and why, is unknown.

Applied evidence is indirect. The clearest canine demonstration of habituation comes from a study designed to test music, not learning (Bowman et al., 2015).

Owner-reported outcomes dominate the treatment data. Effectiveness ratings are perceptions, not measurements (Riemer, 2020).

9.1 What Would Move the Field

Three studies would help. A canine experiment varying stimulus intensity systematically and measuring whether responding decreases or increases, which would put a number on the threshold idea. A comparison of massed and spaced exposure schedules in dogs, to test the spacing prediction directly. And work on individual differences, to identify which dogs are prone to sensitize before a plan is built on the assumption that they will habituate.

9.2 Why the Gap Persists

Habituation is unglamorous and difficult to fund: it involves no intervention to test and no product to sell. It also underlies a large share of everyday advice, which makes the absence of canine data more consequential than its low profile suggests.

Dishabituation has not been demonstrated in dogs. The phenomenon is well established elsewhere and is applied here by analogy (Rankin et al., 2009).

9.3 A Note on Terminology in Practice

Trainers and veterinary behaviorists use these words with reasonable consistency; owner-facing material does not. Where a term is likely to be misread, describing the operation is safer than naming it: how strong the stimulus should be, how often, how long, and what the dog should be able to do while it happens. That description survives translation into a household's everyday routine, which the label rarely does.

10. Conclusion

Habituation and sensitization are the two possible outcomes of the same everyday situation: something happens again and again. The formal characteristics — progressive decrement, spontaneous recovery, potentiation across series, frequency and intensity effects, stimulus specificity and dishabituation — are established across species and were revised by a research workshop in 2009 (Rankin et al., 2009; Thompson & Spencer, 1966), and the dual-process account explains why the same repetition can push responding in either direction (Groves & Thompson, 1970). What decides the direction is intensity relative to the individual's threshold, which is why "he'll get used to it" is sound advice for a puppy noticing a vacuum cleaner across the room and poor advice for a dog that panics at it. Canine data are thin and consistent: dogs habituated to kennel music within a week (Bowman et al., 2015), noise fears increase with age in survey data (Blackwell et al., 2013), and procedures that change what a stimulus means outperformed repeated exposure alone in owner ratings (Riemer, 2020). For practice the rules are short: keep the stimulus below the threshold at which the dog reacts fully, expect responses to return after breaks, do not assume transfer to similar situations, plan for the occasional reset, and judge every exposure plan by whether responses are shrinking or growing.

Key Insights (Takeaways)

• Repetition alone is not a method: it can reduce or increase a response depending on intensity.

• Habituation is not desensitization; the difference is deliberate control over intensity.

• Progress disappears after breaks, and that is a property of the mechanism rather than a failure (Rankin et al., 2009).

• Habituation does not transfer automatically to similar stimuli.

• A single unrelated startling event can restore an old response.

• Dogs habituated to music in a kennel within a week, which is how fast the effect can fade (Bowman et al., 2015).

• If responses are growing across sessions, the plan is sensitizing the dog and has to change.

References

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