The Indication. It’s not an optional extra!

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Poppy clearly indicating the location of her target scent inside this person’s trouser pocket.

What is an Indication?

The indication or alert is the means by which your dog is able to communicate to you that he’s found the location of his target scent source. It’s a behaviour that, after training, your dog will perform “immediately and unprompted” (Cablk et al, 2006) and is usually categorised as being either passive or (pro)-active in nature. In large part this classification is dependent on the degree to which the indication behaviour involves contact, or direct interaction with, the scent source.

I tend to view passive indications as those where the dog makes minimal or no contact with the scent source. For example, your dog might sit or lie down beside the scent source or place his nose on it or simply stare at it. In contrast, the pro-active indication involves far more direct engagement with the scent source and may include behaviours such as scratching, grabbing, biting and retrieving (Hurt et al, 2009).

Barking is another very commonly used indication. As this behaviour doesn’t involve any direct contact with the scent source, it would seem to be just another form of  passive indication, however, as Hurt et al (2009) point out, as a fundamentally frustrative behaviour that “can accelerate into other frustration behaviors” it is probably better described as another form of pro-active indication. In explaining their position, Hurt et al (2009) cited the case of search dogs on the Island of Guam who were trained to detect brown tree snakes and indicate their location by barking. Unfortunately, before very long, this behaviour transformed into pawing and biting and, for the safety of the dogs and the welfare of the snakes, the dogs had to be re-trained.


Does my Scent Detecting dog need an indication?

My short answer to this question is YES and here’s why …

Successful Scent Detecting requires your dog to search for, and locate, his target scent source. Without an indication (either passive or pro-active), you’ll have no means of knowing – for sure – that he’s found it. As Scent Detecting is primarily all about finding, it makes little sense to overlook training the one unambiguous way that your dog has to tell you that he has done just that … his indication.


Why spend time training an indication when I can just watch for a COB?

Recently I’ve noticed a growing trend toward relying on a dogs change of behaviour (COB) to help the handler recognise that their dog has located the scent source. Typical changes in behaviour might include slowing down, speeding up, heightened interest in a particular area of a room, walking on tip-toes with head held high … the list of possibilities is almost endless. Each of these behaviours may help you narrow down the location of the target scent source but may also act to totally mislead you.

As an example of just how poor a COB can be as a means of helping you decide that your dog has located the target scent source, take a little look at this video of Dream working amongst farm machinery.

 

At 23 seconds Dream starts to show a heightened interest along the wall of the tractor shed. This extra interest, or COB – standing on tip-toes, head in the air, staying close to the wall, carefully investigating certain areas – continues until approximately 58 seconds into the video when she then moves on to investigate other parts of the building.

I think it perfectly reasonable to suggest that many handlers, seeing their dog showing this level of interest in a particular area, would be sorely tempted to keep their dog working there until something is ‘found’. That something being a false indication.

Put simply;

The dog’s COB → Increased interest in the area by the handler → Increasing interest in the area by the dog → Further interest in the area by the handler → Increasing psychological pressure on dog to ‘find’ something → False (positive) indication by the dog!

This is just one example of  the ‘Clever Hans Phenomenon’ or ‘Clever Hans Effect’ at work – “where a person or animal can be influenced by subtle and unintentional cueing on the part of a questioner” (Jackson, 2005). If you’d like to know more about how the Clever Hans phenomenon can impact your scent detecting, just follow this link to False Indications, Clever Hans and You

At “Scent : Detect : Find” dogs are trained to search independently, following scent plumes and filaments back to source without undue interference from their human partners. This “hands off” approach to scent detecting goes a long way toward mitigating the Clever Hans Phenomenon. In addition, all dogs are trained an indication behaviour that is totally reliable and unambiguous …. so much so that it is easily recognisable, not only to the handler but, to anyone else who might be looking on.

If you review the video again, you’ll notice that throughout her search Dream’s handler remains out of shot. At all times, Nicky gives Dream the necessary space to work independently. Even when Dream shows heightened interest along the wall of the tractor shed (23 secs – 58 secs), Nicky stays clear of the area and waits for Dream to persuade her, by way of her indication, that her target scent source is there … or, as in this particular search … in a completely different area!

And this is why your dog’s indication is not an optional extra. Having a well trained indication allows Nicky to simply watch her dog until that indication comes.

… Nose Touch. Stillness. Duration.


So, what type of Indication is best – Passive or Pro-Active?

I favour the passive indication and train my own, and other handlers, dogs to place their nose as close to the target scent source as possible and hold it there for a minimum of 5 seconds or until their handler asks them to move away.

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Chewee accurately indicating the location of his target scent; a tiny sticky dot.

This type of indication fits well with your dog’s natural olfactory behaviour. Watch your dog when he’s pottering around the garden. What does he do when he catches an interesting odour? He gets his nose as close to it as possible and, more often than not, will stay fixed to it for a lengthy period of time.

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Brook using her nose to indicate the location of an invisible target scent.

If the scent source is inaccessible to your dog’s nose, for example, placed high up on a wall, or submerged under-water, then this nose touch is transformed easily and quickly into a sustained nose point.

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Bob using his nose to point to his target scent.
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Fynn pointing to his submerged target scent.

My reasons for selecting the passive indication and, more particularly, the

nose touch → nose point (if inaccessible)

include;

Safety – Passive indications help minimise any direct engagement with the target scent source. This can be important where either the target scent itself, or its location, may pose a danger to your dog.

For example, tobacco products such as cigarette and cigar butts, nicotine patches and gum and e-cigarette fluid are all harmful to our dogs (Novotny et al, 2011).

Whilst the target scent may be safe for your dog, its location may not be. Sadly, every year there are a number of reported dog fatalities from Acute Water Intoxication following a period of time playing in water (Toll et al, 1999). Typically, these dogs have been repeatedly diving into water to retrieve items thrown in for them whilst, at the same time, ingesting excessive volumes of water (Becker, 2013). Although the actual prevalence of this condition is difficult to confirm – Becker (2013) believing it to be a relatively rare occurrence – retrieving from water should be an activity that you monitor closely and / or consider restricting.

If your dog has a passive indication, all of these potential dangers are markedly reduced.

Precise and unambiguous – There is no mistaking the precise location of the target scent when your dog’s nose is either touching or pointing toward it. Adding duration to the indication adds even more certainty … your dog isn’t simply having a passing investigatory sniff!

Other passive indications such as a sit or a down cannot match this degree of accuracy particularly in situations where your dog is searching for tiny amounts of target scent, so tiny that you would be hard pressed to see it yourself. 

Can be used in all situations – No matter where the target scent is located – submerged under water, high up on a piece of furniture, buried underground, in an easily accessible position – it will be possible for your dog to either touch his nose to it or point toward its position.

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Abel using his nose touch to indicate “buried treasure”!

 

Preserves the integrity of the scent source – A nose touch, or point, minimises any possible damage to the target scent source. This is unlikely to be the case with a Pro-active indication.

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Luytje pointing out a bundle of cash whilst leaving it completely intact!

 

Requires no further training / re-training in changed circumstances – Starting off your Scent Detecting training with a pro-active indication may seem like a good idea until you decide to change your target scent. At this point, letting your dog interact with it may now be a dangerous or very expensive mistake! Oops.


But a Passive Indication is difficult and time-consuming to train, isn’t it?

Well, that all depends on your point of view …

It certainly requires careful, detailed and thorough training to ensure reliability. Training can take anything from just a few hours or, in a limited number of cases (and for some very specific reasons), a few months to complete and this should all happen BEFORE searching “proper” begins.

Without this careful, early, training you are likely to encounter indication problems further down the line. Far simpler to train a reliable passive indication in the first place than have to add in further, often complex, remedial training at some later point in time including “Show me” or “Where is it?” cues.

The “Show me” or “Where is it?” cue is used, predominantly, within competition scent work circles where time means points means places! For very obvious reasons, an indication with lengthy duration is rarely trained and, as a consequence, any indication that there is may be missed by the handler. The “Show me” cue is a way of asking the dog to return to the location of the target scent and indicate again. I’m afraid I’m not a great fan of this sticking plaster approach to training. Far better I’d say to train the indication behaviour thoroughly in the first place than add in this extra layer of training complexity.

And then there’s the thorny issue of being “just a pet dog owner”. According to this viewpoint, pet dog owners are rarely interested in training a reliable passive indication. … It takes time … It delays their dog from starting to search until the indication training is complete … They aren’t bothered about an indication … They don’t have the training skills … and so on. Certainly this has never been my experience. The majority of my clients are “just pet dog owners” with almost 60 of them having trained reliable passive indications and another 50 or more well on their way.


So … in conclusion …

As Scent Detecting is all about finding, it makes little sense to overlook training the one unambiguous way that your dog has to tell you that he has done just that … his indication.

If you’d like to know how I train a Passive Indication, look out for my next Blog – “Smoothing out the Lumpy Bits; Why it might be wise to teach the indication before the search”. 

And NO … your dog’s indication should never be a scent detecting optional extra.


Final Note

As with all of my blogs, I include a reference list. This allows you to investigate the topic a little further, check out the sources of my information and decide for yourself whether my interpretations of the literature are an accurate reflection of the author’s original work. Happy reading.


© Lesley McAllister – Scent : Detect : Find Ltd 2018

www.scentdetectfind.co.uk

https://www.facebook.com/scentdetectfind/?ref=bookmarks


References / Further Reading

  1. Becker K (2013) Water Intoxication: Too Much of a Good Thing. https://healthypets.mercola.com/sites/healthypets/archive/2013/10/28/water-intoxification.aspx Accessed 15.12.2018
  2. Cablk ME and Heaton JS (2006) ACCURACY AND RELIABILITY OF DOGS IN SURVEYING FOR DESERT TORTOISE (GOPHERUS AGASSIZII). Ecological Applications. 16(5). 1926-1935
  3. Hurt A and Smith DA (2009). Conservation Dogs. IN: Helton WS (Ed) Canine Ergonomics: The Science of Working Dogs. Taylor and Francis Group: London.
  4. Jackson J (2005) The Clever Hans effect – a horse’s tale. Critical Thinking. http://www.critical-thinking.org.uk/pdf/clever-hans.pdf
  5. Novotny TE, Hardin SN, Hovda LR, Novotny DJ, McLean MK, Khan S (2011) Tobacco and cigarette butt consumption in humans and animals. Tobacco Control. 20. 17-20
  6. Toll J, Barr SC, Hickford FH (1999) Acute Water Intoxication in a Dog. Journal of Veterinary Emergency and Critical Care. 9. 1. 19-22.

The Heat Is On: Summer Temperatures and Our Scent Detecting Dogs

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It’s hot out there!

Please Note

The focus of this Blog is our dogs’ normal thermoregulatory mechanisms and how these might impact on their Scent Detecting activities during the warmer summer months. If you feel that your dog is struggling in any way with the heat, SEEK IMMEDIATE QUALIFIED VETERINARY ASSISTANCE.


With day-time temperatures in the UK currently reaching anything between 25°C and 30ºC, social media has seemingly gone into overdrive with dire warnings of the dangers this heat may pose to our dogs. Owners are being advised to curtail all usual activities in a bid to keep their dogs cool and many sporting events have been cancelled or postponed. But what about our scent detecting dogs? Can they continue to work in these high temperatures or should we keep them in the shade until the cooler weather returns?

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Should we retire our Scent Detecting dogs until the temperature drops?

Some background …

Without sweat glands, panting (with accompanying evaporative cooling from the upper respiratory tract) is the main means by which our dogs are able to maintain their normal body temperature of between 37.5°C and 39.1°C (Gazit et al, 2003. Jordan et al, 2016). Any deviations from this narrow range can interfere with normal cellular function (Bear et al, 2016) and, in extreme cases, may result in death.

Our dogs are considered thermally stable when any extra heat they gain is matched by the equivalent amount of heat loss (Stanley, 1980). The thermoneutral zone (TNZ) is the environmental temperature range (between 20°C – 30°C) at which our dogs can maintain their normal body temperature without having to expend energy to either increase heat production or heat loss (Jordan et al, 2016).

The total heat load our dogs experience is made up of both environmental and metabolic factors. If the ambient temperature exceeds our dogs’ body temperature then they will absorb heat from the environment (Jordan et al, 2016). While the heat produced by our dogs’ organs remains fairly constant, heat production by their skeletal muscle is dependent on their activity levels. Up to 80% of our dogs’ body heat is produced by their working muscles (Stanley, 1980).


A little bit of anatomy and physiology … well … quite a lot actually!

Cold– and Warm-sensitive neurons, found in the pre-optic area of the anterior hypothalamus of our dogs’ brains, detect (and respond to) changes in circulating blood temperature. In the case of any rise in temperature, there is a reduction in the release of Thyroid Stimulating Hormone (TSH) from the anterior pituitary gland resulting in a slowing down of our dogs’ metabolism. Blood is shunted toward our dogs’ peripheries to help dissipate heat through the skin and you might start to notice some behavioural changes including a desire to seek shady areas. In addition, our dogs involuntary motor response is to pant (Bear et al, 2016. Hardy et al, 1964).


If you’d like to find out a little more about the hypothalamus and the pre-optic area … just follow these three links.

https://www.neuroscientificallychallenged.com/blog/2014/5/10/hypothalamus-know-your-brain?rq=hypothalamus

https://www.neuroscientificallychallenged.com/blog/2-minute-neuroscience-hypothalamus-and-pituitary-gland?rq=hypothalamus

https://www.neuroscientificallychallenged.com/blog/know-your-brain-preoptic-area?rq=Temperature%20regulation


Goldberg, et al (1981) have identified three patterns of breathing exhibited by dogs’ as their need for evaporative cooling increases either because of increasing environmental temperature or exercise load. As previously mentioned, up to 80% of our dogs’ body heat is produced by working skeletal muscle!

  • Pattern I – Inhalation and Exhalation through the nose.
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Pattern I – Inhalation and Exhalation through the nose

This pattern of breathing is characteristic of the resting dog and, in Goldberg, et als (1981) study was observed in dogs who were either resting in environmental temperatures below 26°C or running at slow speeds in cooler temperatures (10°C).

As inhaled air travels to the lungs, it is warmed and humidified by the moist nasal mucosa. In turn, the nasal mucosa is cooled. On exhalation, air loses its heat to the now, cooler, nasal mucosa and water condenses. This counter-current heat exchange system helps our dogs conserve heat and moisture that might otherwise be lost to the external environment.

In contrast, when our dogs’ need to lose heat, this heat-exchange mechanism can be circumvented by a) vasodilation of the nasal mucosa between inhalation and exhalation and b) switching to exhalation through the mouth as in Patterns II and III.

  • Pattern II – Inhalation through the nose. Exhalation through the nose and mouth.
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Pattern II – Inhalation through the nose. Exhalation through the nose and mouth

Goldberg, et al (1981) observed this pattern of breathing in dogs either resting quietly in environmental temperatures ranging between 30°C and 42°C or during exercise (except when running slowly at low temperatures as in Pattern I). In these types of environmental and exercise conditions, dogs breathing was seen to oscillate between patterns II and III.

The dogs normal, resting, respiratory rate of between 10-35 breaths / minute (average 24 breaths / minute) increases to approximately 250 breaths / minute. Interestingly, this panting frequency matches the active sniffing frequency of the scent detecting dog (3-7Hz = 3-7 sniffs / second). Panting and active sniffing frequencies are thought to minimise energy expenditure (Craven et al, 2010. Settles et al, 2002).

Although our dogs can now by-pass the heat exchange system in the nose and increase heat loss by exhaling through their mouths, heat loss still occurs mainly in the nose. Vasodilation of the nasal mucosa, with extra moisture being provided by two lateral nasal glands (Steno’s glands) which open through ducts just inside our dogs’ noses, increases evaporative cooling. As breathing rate increases, so does secretion of fluid from these glands (Blatt, et al, 1972).

  • Pattern III – Inhalation through the nose and mouth. Exhalation through the nose and mouth.
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Pattern III – Inhalation and Exhalation through the nose and mouth

This pattern of breathing is seen in situations of severe heat stress. The amount of time our dogs use this pattern of breathing increases alongside increases in environmental temperature and exercise load. According to Goldberg, et al (1981), exercise will increase our dogs heat load more so than an increasing environmental temperature.

Lingual blood flow (blood flow to the tongue) increases during moderate heat stress alongside Salivation. Saliva production is governed by the hypothalamus as one of its thermoregulatory responses. Evaporative cooling takes place as dry air is inhaled across the moist tongue and mouth.

Unfortunately, although these three respiratory patterns can be useful signposts to us with regard to how our dogs are coping with the environmental temperature or exercise, Baker, et al (1989) warn that dehydrated dogs will reduce thermoregulatory evaporation in order to reduce water loss. In short, a dehydrated dog will have a lower respiratory rate with a consequent higher body temperature as panting is reducedBaker, et al (1989) observed a rapid recovery of panting in their study dogs after they were able to drink water.


So … What does all of this mean for our Scent Detecting dogs?

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Our dogs cannot sniff and pant at the same time

Our dogs’ ability to detect their target odour is largely dependent on their ability to sniff  (Mainland et al, 2006). During normal breathing, approximately 12-13% of inspired air will reach the chemosensory area of our dogs noses – the olfactory epithelium – but, importantly, active sniffing will increase this amount by another 2-3% (Craven et al, 2010).

In high temperature environments or, after strenuous physical activity, our dogs’ need to divert attention away from the scent detecting task (and active sniffing) and toward maintaining their body temperature within normal limits (Gazit et al, 2003). As previously discussed, this requires our dogs to pant.

Unfortunately, when our dogs pant, not only are they NOT actively sniffing but “a large turbulent jet is expired from the mouth, obscuring any scent-bearing air currents in the vicinity. The dog must therefore normally stop panting in order to sniff” (Settles et al, 2002). Our dogs cannot sniff and pant at the same time!

In Gazit et als (2003) study investigating explosives detection by sniffer dogs working in hot climates, they found a decrease in “olfactory efficiency [resulting] mainly from overheating [which caused] physiological and behavioural resources to be diverted from concentration on the assigned task and applied instead to methods of body cooling”. Interestingly, however, after training in, and exposure to, high temperature working environments, their scent detecting performance improved. This is likely to have been due to the process of acclimatization whereby the animal becomes physically adjusted to, and able to tolerate, the temperature of their environment (University of Iowa: Hospitals and Clinics, 2016). Amongst other things, acclimatization to heat decreases the temperature threshold at which heat dissipation mechanisms are activated (Bruchim et al, 2014. Horowitz, 1998); Our dogs’ “cooling strategies” come into play much sooner than they would pre-acclimatization.

According to Horowitz (1998), “heat acclimation is switched on in response to persistent, moderate ambient heat and takes time to develop but is long acting (several weeks)”. Partial acclimatization may take from 10 – 20 days while full acclimatization may take up to 60 days (Jordan et al, 2016). Certainly, from a personal perspective, this rings true for me. Now, a number of weeks into these unusually high UK temperatures, my own dogs are far more active than they were in the early days of this ongoing heatwave.


So … Should we retire our Scent Detecting dogs until the temperature drops? 

With a little care, thought and planning, Summer Scent Detecting is still perfectly possible, however, each of us must decide for ourselves whether it is safe to proceed.


A few points to keep in mind

  1. Our dogs pant in response to an increasing body temperature – we need to keep Scent Detecting sessions short and, wherever possible, work in areas with plenty of shade / protection from the sun.
  2. Panting is an involuntary motor response which helps our dogs’ maintain their body temperature within normal limits – they cannot choose to stop panting and continue sniffing. Scent Detecting activities may take longer than expected as our dogs pant rather than sniff. Ensure plenty of “down-time” and allow our dogs’ to take extra breaks whenever they want to.
  3. Our dogs will cease to pant (and overheat) if they are dehydrated – Ensure a plentiful supply of fresh drinking water at all times. Do not “force” a dog to drink.
  4. Remember that up to 80% of our dogs’ body heat is produced by their working skeletal muscles – Scent Detecting may be a far safer activity for our dogs in high temperature environments than other, more strenuous, sports and hobbies. No dog should be forced to exercise.
  5. Take extra care if you own any of the brachycephalic breeds, eg; pug – the anatomy of their head is likely to interfere with their ability to pant and regulate their temperature (Stanley, 1980).
  6. Our dogs’ can acclimatize to high ambient temperatures but it takes time – Do not expect our dogs’ to be working as enthusiastically, or at as fast a speed, as they would normally during the cooler months.

Happy Scent Detecting!

 


Final Note

As with all of my blogs, I include a reference list. This allows you to investigate the topic a little further, check out the sources of my information and decide for yourself whether my interpretations of the literature accurately reflect the author’s work. Happy reading.


© Scent : Detect : Find Ltd 2018


References / Further Reading

  1. Baker M A and Turlejska E (1989) Thermal panting in dehydrated dogs: effects of plasma volume expansion and drinking. European Journal of Physiology. 413. 511-515.
  2. Bear M F, Connnors B W and Paradiso M A (2016) Neuroscience. Exploring the Brain. 4th Ed. Philadephia: Wolters Kluwer.
  3. Blatt C M, Taylor C R and Habal M B (1972) Thermal Panting in Dogs: The Lateral Nasal Gland, a Source of Water for Evaporative Cooling. Science. 804-805.
  4. Bruchim Y, Aroch I, Eliav A, Abbas A, Frank I, Kelmar E, Codner C, Segev G, Epstein y and Horowitz M (2014) Two years of combined high-intensity physical training and heat acclimatization affect lymphocyte and serum HSP70 in purebred military working dogs. Journal of Applied Physiology. 117. 112-118.
  5. Craven B A, Paterson E G and Settles G S (2010) The fluid dynamics of canine olfaction: Unique nasal airflow patterns as an explanation of macrosmia. Journal of the Royal Society. Interface. 7. 933-943.
  6. Gazit I and Terkel J (2002) Explosives detection by sniffer dogs following strenuous physical activity. Applied Animal Behaviour Science. 81. 149-161.
  7. Goldberg M B, Langman V A and Taylor C R (1981) Panting In Dogs: Paths Of Airflow In Response To Heat and Exercise. Respiration Physiology. 43. 327-338.
  8. Hardy J D, Hellon R F and Sutherland K (1964) Temperature-Sensitive Neurones in the Dog’s Hypothalamus. Journal of Physiology. 175. 242-253.
  9. Horowitz M (1998) Do Cellular Heat Acclimation Responses Modulate Central Thermoregulatory Activity? News Physiological Science. 13. 218-225.
  10. Jordan M, Bauer A E and Croney C (2016) Temperature Requirements for Dogs. Are they tailored to promote dog welfare? Purdue Extension. October. 1-3.
  11. Mainland J and Sobel N (2006) The Sniff is part of the Olfactory Percept. Chem. Senses. 31. 181-196.
  12. Settles G S, Kester D A and Dodson-Dreibelbis L J (2002) The External Aerodynamics of Canine Olfaction. IN: Barth F G, Humphrey J A C and Secomb T W (Eds) Sensors and Sensing in Biology and Engineering. New York: Springer.
  13. Stanley S M (1980) A Study of Heat Stroke and Heat Exhaustion in the Dog. Iowa State University Veterinarian. 42. 24-27.
  14. University of Iowa: Hospitals and Clinics (2016) Acclimatization: Adjusting to the Temperature. https://uihc.org/health-topics/acclimatization-adjusting-temperature. Accessed 1.8.2018

The Tortoise and The Hare … and we all know who won that particular race!

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Showing a clean pair of heels

It’s hard not to be impressed by the dog who speeds around the search area appearing totally engaged with the task in hand as he tries to locate his target scent. In comparison, the dog who moves more slowly is often overlooked in favour of his flashier counterpart. But, where scent detecting is concerned, speed might not be everything and selecting the right breed for the job may be more a matter of taste than a matter of science.

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Speed isn’t everything

In the UK, the most commonly selected breeds for scent detecting work include (amongst others) Labradors, Spaniels, Border Collies, German Shepherds and Malinois. But which breed is best?

Gadbois and Reeve (2014) favour the Border Collie, basing their preference, amongst other things, on the breed’s apparent persistence and good sniffing ability. They propose that certain breeds have higher baseline levels of dopamine than others which, they state, “raises the intriguing possibility that baseline dopamine levels may have a direct impact on cognition, motivation, learning, and overall olfactory behaviour and performance”. They refer to this possibility as their “dopamine hypothesis” and link this to the notion of “work ethic”. Other breeds they single out as “dopamine dogs” include Belgian Malinois and Jack Russell Terriers. More about dopamine in a future blog.

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Gadbois and Reeve (2014) favour the Border Collie. Floss in action.

All that said, Hall, et al (2015) and Rooney and Bradshaw (2004) argue that the choice of working dog may have far more to do with historical precedent than any real evidence of superior scent detecting ability. According to Johnen, et al (2017), good quality empirical studies remain thin on the ground and as Jamieson, et al (2017) warn, “continually selecting the same dog breeds, without inspecting other breeds, may reduce the effectiveness of detection dog programs”.

Interestingly, in McCulloch, et als (2006) study investigating the ability of dogs to detect early- and late-stage lung and breast cancer, it was a mix of pet dogs (rather than ‘working’ dogs) with only basic puppy training who (in a matter of weeks) were able to accurately identify breath samples from lung and breast cancer patients.

Hall, et al (2015) argue for the need for “direct behavioural measurement of assumed behavioural breed differences”. Contrary to all expectations, in their 2015 study comparing the scent detecting abilities of German Shepherds, Greyhounds and Pugs, the Pugs significantly outperformed both other breeds.

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The Pug … a surprisingly good scent detecting breed?

Whilst Hall, et als (2015) study may not have persuaded you to purchase your first scent detecting pug … well, not yet anyway … it does raise another important question. Did the Pugs succeed because of their superior olfactory ability or because of the training methods employed in the study?

In an attempt to address this question, Polgar, et al (2016) developed a simple strategy to measure differences in olfactory ability that did not require any pre-training. Raw turkey meat was placed under 1 of 4 ceramic pots. Five levels of difficulty were arranged by way of decreasing numbers of holes in the ceramic pots. Subjects were assigned to one of four groups; dog breeds selected for their scent detecting abilities, dog breeds selected for other purposes, dog breeds with short noses and hand-reared grey wolves. The dogs / wolves were led along the row of pots to identify, by scent alone, which contained the meat. Dog breeds selected for scent detecting work out-performed both the short nosed breeds and those bred for other purposes. At the most difficult level, wolves and the scenting breeds performed better than chance.

Interestingly, according to Maejima, et al (2007), “research with drug detection dogs failed to reveal any significant link between performance and theoretically relevant genotypes” however, Lesniak, et al (2008) argue that breed and heredity may have some influence on scent detecting ability … “there may be a relation between a certain genotype at a particular locus and the ability of more accurate scent detection of particular volatile organic compounds”. This raises the intriguing possibility that not only may some breeds (or individuals within a breed) have better olfactory abilities than others but that some breeds (or individuals within a breed) may have better olfactory abilities when tasked to detect particular target scents.

Similarly, we also show variation in our ability to detect certain odours. Odour sensitivity is heritable. One well referenced example of this “specific anosmia” relates to the ability to detect a sulphurous odour in urine following asparagus consumption (Pelchat, et al (2011)). Some of us can smell it, some of us can’t. Could our dogs also have “specific anosmias”?

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Asparagus – Can you smell it?

Returning then to the original subject of this blog. Tortoise or Hare? Accuracy or speed? According to Helton (2009) “a dog may quickly find substances, but may miss targets because of haste. A dog may also be very slow to find substances, but based on a methodical approach may miss few or no targets”. Self-evidently, a dog whose performance is both accurate and fast seems hugely desirable and, as Helton (2009) suggests, “training and practice can markedly improve skill” … a combination of speed and accuracy, perhaps?

But, can training and practice really alter your dog’s general “approach” (or speed) to scent detecting work? Can you turn your slow and thoughtful Rottie into a speedy working Cocker? Experience would suggest not. Each breed (and every dog within that breed) comes with its own, highly individual, set of characteristics; a mixture of heredity and past life experiences. Far better to work with the dog you have in front of you than attempt to turn him into something he can never be. For me, one of the big enjoyments of working with so many different breeds is their very different styles of working. Each and every one of them brings something new to scent detecting and helps break down any stereotypical views of what different breeds might be capable of. Tortoise or Hare … I’ll take both please!

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Slow and thoughtful Jim
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Speedy Brook

 

 

 

 

 

 

 

 

So, a thought to leave you with. When Helton, et al (2009) asked a trainer which breed was best as an explosives detector dog, his reply was … “depends on where you live, you see here in the United States it is the Labrador Retriever, in the United Kingdom it is the Springer Spaniel, in Belgium it is the Belgian Malinois, in Germany the German Shepherd, and in Norway, they are pushing the Norwegian Drever, a dog most people have never heard of. Personally, I think it is all goofy, pick any dog you are comfortable with”.

And, if you think a Norwegian Drever might be the scent detecting dog for you … just follow this link … https://www.skk.se/en/NKU-home/nordic-dog-breeds/sweden/drever/

© Lesley McAllister – Scent : Detect : Find Ltd 2018

References / Further Reading

  1. Gadbois S and Reeve C (2014) Canine Olfaction: Scent, Sign, and Situation. IN: Horowitz A (Ed) Domestic Dog Cognition and Behavior. The Scientific Study of Canis Familiaris. London: Springer.
  2. Hall N J, Glenn K, Smith D W and Wynne D L (2015) Performance of Pugs, German Shepherds and Greyhounds (Canis Lupus Familiaris) on an Odor Discrimination Task. Journal of Comparative Psychology. 129(3). 237-246.
  3. Helton W S (2009) Overview of Scent Detection Work. Issues and Opportunities. IN: Helton W S (Ed) Canine Ergonomics. The Science of Working Dogs. London: Taylor and Francis Group.
  4. Helton W S, Feltovich P J and Velkey A J (2009) Skill and Expertise in Working Dogs. A Cognitive Science Perspective. IN: Helton W S (Ed) Canine Ergonomics. The Science of Working Dogs. London: Taylor and Francis Group.
  5. Jamieson L T J, Baxter G S and Murray P J (2017) Identifying suitable detection dogs. Applied Animal Behaviour Science. 195. 1-7.
  6. Johnen D, Heuwieser W and Fischer-Tenhagen C (2017) An approach to identify bias in scent detection dog testing. Applied Animal Behaviour Science. 189. 1-12.
  7. Lesniak A, Walczak M, Jezierski T, Sacharczuk M, Gawkowski M and Jaszczak K (2008) Canine Olfactory Receptor Gene Polymorphism and Its Relation to Odor Detection Performance by Sniffer Dogs. Journal of Heredity. 99 (5). 518-527
  8. Maejima M, Inoue-Murayama M, Tonosaki K, Matsuura N, Kato S, Saito Y, Weiss A, Murayama Y and Ito S (2007) Traits and genotypes may predict the successful training of drug detection dogs. Applied Animal Behaviour Science. 107. 3-4. 287–298.
  9. McCulloch M, Jezierski T, Broffman M, Hubbard A, Turner K and Janecki T (2006) Diagnostic Accuracy of canine Scent Detection in Early- and Late-Stage Lung and Breast Cancers. Integrative Cancer Therapies. 5(1). 30-39
  10. Pelchat M L, Bykowski C, Duke F F and Reed D R (2011) Excretion and Perception of a Characteristic Odor in Urine after Aspragus Ingestion: a Psychophysical and Genetic Study. Chemical Senses. 36. 1. 9-17.
  11. Polgar Z, Kinnunen M, Ujvary D and Gacsi M (2016) A Test of Canine Olfactory Capacity. Comparing Various Dog Breeds and Wolves in a Natural Detection task. Plos One. May. 1-14.
  12. Rooney N J and Bradshaw J W S (2004) Breed and sex differences in the behavioural attributes of specialist search dogs – a questionnaire survey of trainers and handlers. Applied Animal Behaviour Science. 86. 123-135.

Blank Searches. Yes or No?

The Blank Search – where your dog is required to search an environment that doesn’t contain his target scent – continues to be a common feature of many Scent Detecting Courses. If you’ve already spent many hours encouraging your dog to search for, and locate, his target scent, why might you want (or need) to train your dog to search an area when it isn’t there?

Two common responses to this question, include;

  1. Blank searches will increase your dog’s motivation to search.
  2. Future search areas may not contain your dog’s target scent. He needs to be ‘trained’ in preparation for this.

So, let’s examine each of these claims in turn and see just how much water they hold.

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Do these claims hold any water?

Blank searches will increase your dog’s motivation to search.

In a study by Gazit, et al (2005), seven highly trained explosives detection dogs took part in a series of 4 experiments.

In the first experiment the dogs were trained alternately on two very similar paths. Path A always contained 5 hidden explosives whilst Path B contained no explosives. In just a few sessions the dogs demonstrated a significant decrease in search behaviour on Path B but not on Path A. This seems to offer the first, albeit small, piece of evidence that blank searches may actually reduce, rather than increase, a dog’s motivation to search.

In the second experiment the dogs were trained exclusively on Path B. 1 explosive was hidden on the path every 4 days. The dogs detection rates during this second experiment were found to be significantly lower than in the first experiment.

The third experiment was conducted on Path C. As in the second experiment, only 1 explosive was hidden on this new path every 4 days. Interestingly, both the probability of detection and motivation to search were significantly higher than in second experiment despite the number of hidden explosives being the same in both experiments.

In the fourth experiment the dogs were returned to Path B. Despite being trained for another 12 days, with 1 explosive being hidden on the path on each of the daily sessions, the dogs failed to demonstrate the levels of motivation that they had previously shown when searching any of the other paths that had usually contained explosives.

According to Gazit, et al (2005), these findings suggest that even a highly trained Explosives Detection Dog will quickly learn that a specific area does not contain explosives and, as a result, the dog will be “less motivated to search and will miss newly placed targets”.

As the Gazit, et al (2005) study demonstrates, the loss in search and detection performance following exposure to only a small number of blank searches, is ‘context specific’. In other words, the decline in the dogs performance is limited to the area in which they have been exposed to the blank search condition. These findings are further supported by Porritt, et als (2015) study into performance decline in search dogs. They state that “without the opportunity to find rewarded targets in repetitive search environments, scent detecting dogs will become ineffective after a short period, and this performance decrement is hard to reverse”.

So, what are the implications of these study results for your own scent detecting training? Because of the speed at which this decline in motivation to search is evidenced, I no longer set up any blank searches for my own dogs and actively discourage my clients from doing so too. Although this reported decline in motivation is said to be context specific, this may actually cause you extra difficulties. For many of you, choice of training area can be very limited and if you practice blank searches in your regular venue it seems likely that this will be to the detriment of any future training in this same area. As Gazit, et al (2005) conclude, “if the [search] behavior is extinguished in a specific context, it will be very difficult to restore that [search] behavior in that context”.

Some anecdotal evidence, provided by my own two dogs, may lend further support to my ‘Just say NO to Blank Searches‘ training stance. ‘L’ has experienced a number of blank searches in her scent detecting training career. ‘BB’, has no experience of blank searches. Although it has been many years since ‘L’s’ last blank search, her motivation to search is, in my opinion, markedly reduced. She has a tendency to slow down and eventually stop searching if she doesn’t locate her target scent within just a few minutes. In contrast, ‘BB’s’ motivation to locate the target scent increases (faster and more thorough) the longer the search continues. ‘L’ has been ‘fooled’ in the past – asked to search when the area was blank. ‘BB’ has never experienced this ‘deception’ – if asked to search all his experiences tell him that his target scent will be present, he just needs to continue searching (perhaps more thoroughly) until he can locate it … and he does!

It seems worth asking ourselves here whether it’s reasonable to cue our dogs to perform a  behaviour that we know, because of the set-up, they won’t be able to complete? One example that comes immediately to mind is the practice of pretending to throw a toy. The dog rushes off to find it, searches around for a while, looks back, ‘puzzled’, at the ‘thrower’ and, eventually, gives up. Personally, I dislike this practice and I’m pretty sure the dog isn’t too keen on it either!

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Pretending to throw a toy …

Similarly, with the blank search, the dog is cued to perform a very specific behaviour chain – search an area, locate the target scent and indicate its location. Except … it can’t. It’s been set-up to fail. There is no target scent to find. Not only does this practice run the very real risk of diminishing the dog’s motivation to search but I wonder what it does for the relationship between dog and handler? Worth thinking about?

Future search areas may not contain your dog’s target scent. He needs to be ‘trained’ in preparation for this.

For the pet, hobby or sports dog I can think of no convincing reason that they should ever have to search an area devoid of target scent. Unfortunately, because blank searches continue to appear in the competition scent-work arena, handlers may feel that they have little option but to train for this possibility. I would simply urge caution.

In contrast, blank searches are a very real, everyday, experience for the working dog team; those that earn their living by scent detecting. But does this have to be the case?

According to Porritt, et al (2015) “a co-trained, non-contraband odour, secreted in a dog’s working environment and contingently reinforced upon being found, acts to maintain performance in finding contraband target odours that would be rarely encountered during a dog’s working life”.

In Porritt, et als (2015) study, 21 labrador retrievers were trained to detect 3 ‘contraband’ odours (explosives) and 1 ‘non-contraband’ odour. They were then exposed to a number of different experimental search conditions. The group of dogs who had worked extensively with the non-contraband odour showed “little difference in their detection on non-explosive and explosive targets in the test phase. … maintenance of expectation to find any target was sufficient to maintain attention to all odour targets”.

So, what does this all mean? Put simply, it suggests a highly practical method by which the blank search problem can be managed. Working dogs can be trained to detect multiple scents (Williams and Johnston (2002) suggest that dogs can be trained to detect up to ten different scents) including one that can be placed in the working environment prior to a search to ensure that there is always a find for the dog. A highly practical solution to the blank search problem!

Blank searches. Yes or No? I think you know my answer.

 

© Scent : Detect : Find Ltd 2018

References / Further Reading

  1. Gazit I, Goldblatt A and Terkel J (2005) The role of context specificity in learning: The effects of training context on explosives detection in dogs. Animal Cognition. August. 143-150.
  2. Porritt F, Shapiro M, Waggoner P, Mitchell E, Thomson T, Nicklin S and Kacelnik A (2015) Performance decline by search dogs in repetitive tasks, and mitigation strategies. Applied Animal Behaviour Science. 166. 112-122.
  3. Williams M and Johnston J M (2002) Training and maintaining the performance of dogs (canis familiaris) on an increasing number of odor discriminations in a controlled setting. Applied Animal Behaviour Science. 78(1). 55-65.

False Indications, Clever Hans and You

In Berlin, during the late 1800’s, a horse named Hans started to demonstrate some amazing mathematical abilities. When asked a variety of computational questions, Hans would respond by stamping his hoof the correct number of times. According to his owner, Wilhelm von Osten, Hans could also tell the time, and successfully tackle more complex calculations (Jackson, 2005).

Initial investigations, by Professor Carl Stumpf, could find no evidence of cheating or trickery. Hans did, indeed, seem to be a very clever horse but not, perhaps, in the way that was first thought!

Hans with Osten
Hans and his owner, Wilhelm von Osten. (https://commons.wikimedia.org/wiki/File:Osten_und_Hans.jpg)

During 1907, further investigations, led by Professor Oscar Pfungst, reached the conclusion that, rather than being able to count, Hans was responding to the subtle postural and facial cues of his owner and other onlookers. Hans could only correctly answer questions that his questioner also knew the answers to. Additionally, Hans was unable to give a correct response if his questioner was hidden from view (Samhita and Gross, 2013).

What became known as the ‘Clever Hans Phenomenon’ or ‘Clever Hans Effect’ – “where a person or animal can be influenced by subtle and unintentional cueing on the part of a questioner” (Jackson, 2005) – led directly to the development of the “double blind” approach within scientific investigations; where neither the investigator nor the subject knows who is in the test or control groups.

So, what has the ‘Clever Hans Phenomenon’ got to do with you and your Scent Detecting dog? Well, just like Hans, your dog recognises and responds to the subtle (and not so subtle) cues delivered by those around him … including you, his handler!

This effect can be incredibly powerful and can influence your dogs actions in the most profound ways. In an interesting study by Szetei and Miklosi (2003), almost 50% of the study dogs would go to an empty bowl indicated to them by a person pointing to it rather than to a bowl in which the dog had previously seen and smelt food!

In another study by Lit, et al (2011), 18 drug / explosive detection dog and handler teams were given a number of detection tasks to complete. None of the tasks contained drug / explosive scent. In other words, they were all ‘blank’ searches. Any alerts / indications that the dogs gave would be incorrect, or, ‘false positive’ indications. Two of the detection tasks included a small piece of paper that falsely marked a scent location and two other detection tasks contained a decoy scent (toy / food).

In the detection tasks that included the false paper markers the handlers reported that their dogs alerted more at the marked locations than in other parts of the search area. According to Lit and her co-authors, when the handlers believed that there was scent present in the search area (paper markers) they were more inclined to claim that their dogs had indicated on a ‘target scent’; a ‘false positive’ indication. As Lit, et al (2011) state, this would seem to confirm that “handler beliefs affect outcomes of scent detection dog deployments”.

Interestingly, in the same study, when there were no paper markers present, there were more ‘correct’ (no indication) searches. It would seem then that we are as vulnerable to the ‘Clever Hans Effect’ as our dogs; taking cues from our environment and acting on our beliefs about these cues.

It’s worth noting here that, at the time of publication, the Lit, et al (2011) study received considerable criticism. If you’d like to know a little more about this debate, here are two interesting links to follow;

https://www.npr.org/2017/11/20/563889510/preventing-police-bias-when-handling-dogs-that-bite

http://swgdog.fiu.edu/news/2012/swgdog-response-to-lit-k9-study/swgdog_response_to_lit_study.pdf

So, how can you help guard against the ‘Clever Hans Effect’ in your own Scent Detecting work?

Practice more ‘Blind Searches’ – Find a training partner, someone who can hide your dog’s target scent for you. If you don’t know where it’s located you’ll be less likely to influence your dog’s searching behaviour. Remember, Hans could only ‘answer’ questions that his questioner could also answer. Your dog will now have to ‘answer’ the scent detecting question for himself.

Keep an OPEN mind – As Lit and her co-authors (2011) demonstrated, even a Blind Search doesn’t prevent you from starting to second-guess where the target scent might (or might not) be located. Something in the search area – for Lit, et al’s (2011) subjects it was a small piece of paper, for you it might be a chair that’s been moved – can cause you to encourage your dog  into, or away from, a certain area. Beware of any internal dialogue that tells you “He wouldn’t have put it there” because, guess what … he HAS put it there! I fell into this trap AGAIN just a few days ago. Believing I knew where the target scent wouldn’t be resulted in me directing my dog away from the correct search area. Ho hum. Time to follow my own advice!

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Keep an open mind

Allow your dog to work independently – I’m a big advocate of ‘Free Searching’. By this I mean letting your dog work away from you, choosing his own route around the search area without close-control and direction from you. Look out for a future Blog focusing specifically on this topic. Giving your dog space to work and, more importantly, resisting the temptation to start searching yourself – looking in boxes, opening cupboards, peering under furniture – helps alleviate any tendency that your dog might have to watch for cues from you rather than search the environment carefully himself. As the saying goes, “Why have a dog and bark yourself”? If you start to show interest in a particular part of the search area it’s highly likely that your dog will too. As soon as this happens, believing that your dog has located the target scent source, you’ll start to look harder yourself. A vicious circle with the almost inevitable result – a false indication from your dog prompted by inadvertent cues from you.

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Poppy working independently

Consider your audience – Like Hans, your dog will respond to cues from any onlookers in the search area. Whenever possible, try to set up searches where your audience is also unaware of the location of the target scent. If they don’t know where it is they’re less able to inadvertently influence your dog’s search. Encouraging your audience to talk to one another can be helpful too. The more attention they’re giving one another during the search the less attention they’ll be paying to your dog. Less helpful is ‘audience silence’ and ‘breath-holding’ as your dog comes close to his target scent.

With “increasing evidence for an acute sensitivity to human gestures and attentional states” in our dogs (Udell, et al 2010), guarding against the Clever Hans Phenomenon can be problematic but an essential consideration in the development of a reliable scent detecting dog.

© Scent : Detect : Find Ltd 2018

References / Further Reading

  1. Jackson J (2005) The Clever Hans effect – a horse’s tale. Critical Thinking. http://www.critical-thinking.org.uk/pdf/clever-hans.pdf
  2. Lit L, Schweitzer J B and Oberbauer A M (2011) Handler beliefs affect scent detection dog outcomes. Animal Cognition. 14: 387-394
  3. Samhita L and Gross H J (2013) The “Clever Hans Phenomenon” revisited. Communicative and Integrative Biology. 6:6. November – December
  4. Szeiti V and Miklosi A (2003) When dogs seem to lose their nose: an investigation on the use of visual and olfactory cues in communicative context between dog and owner. Applied Animal Behaviour Science. Sept 5. Vol 83. Issue 2. 141-152
  5. Udell M A R, Dorey N R and Wynne C D L (2010) What did domestication do to dogs? A new account of dogs’ sensitivity to human actions. Biological Reviews. 2010. 85. 327-345