There’s Nothing to See Here; why your Scent Detecting dog doesn’t need an audience

This may come as a bit of a surprise to some of you but I don’t allow dogs to ‘spectate’ when another dog is working.

NO … “But my dog is friendly” dogs.

NO … “But they know each other and play together” dogs.

NO … “But they live together” dogs.

NEVER, EVER, EVER! And I apply this rule to my own dogs too.

If you’re used to attending any training, competition or social events with your dog (where it seems ‘de rigueur’ to keep your dog with you at all times including within an audience setting) you’ll appreciate that my stance is definitely not the norm. For some of you, my position will be irritating and inconvenient, for others it’ll come as a blessed relief; I give you permission to give yourself, and your dog, a break!

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I don’t allow dogs to spectate when another dog is working. NEVER, EVER, EVER!

So, what are my reasons? Well, two-fold really. Firstly there are behavioural considerations for both the working and the audience dogs. Secondly there are Scent Detecting considerations that will have a direct impact on your dog’s training.


1. Behavioural Considerations

I live with two dogs, L and BB. They’ve been together now for almost 4 years and apart from the very occasional mild disagreement about something or other, their relationship is largely peaceable. In short, they’re ‘good mates’ … they understand one another.

As evidence for (what some might say are) my wild claims of sibling harmony, take a look at some of these photos … and … no … they’re not related.

I think you’d agree; they’re a team!

So, they rub along together very nicely, they know each other well, they play and live together … why on earth will I not allow them into the search area together while one or other of them is working?

Well, take a little look at this short video clip.

I’m in a field with L and BB. L is recalling to me very slowly. At 3 seconds she comes to a halt and turns her head away. At 9 seconds I think I see her lip her licks. Because of her dark coat colour, it’s not very clear, but I do notice her swallowing. Out of shot, lying beside me, is BB. L’s behaviour tells me that something that BB is doing is causing her some concern … enough to stop her in her tracks and use a number of “Calming Signals” – slowing down, head turning, lip-licking (Rugaas, 2006). L is attempting to defuse any potential conflict between herself and BB. When I look down at BB he’s staring intently at L, crouched and ready to pounce. He might think it’s a game … she quite obviously doesn’t … or … perhaps he doesn’t like her direct approach and she’s attempting to signal her good intent toward him? Either way, I’m in no doubt that they are in ‘conversation’ with one another.

Rugaas (2006) describes calming signals as a “life insurance policy”. Amongst other things they help “prevent things from happening … [and importantly] … make the others involved feel safer and understand the goodwill the signals indicate”. Mariti et al (2017) view these signals as having “a communicative role” and, as a social species, being able to communicate clearly with one another is not an optional extra for your dog.

Now imagine L and BB together in a search area; BB spectating perhaps while L attempts to work. As I think the video illustrates, despite knowing each other well, living in the same house, playing, sleeping and eating together, the need to communicate their intent toward one another at any given moment in time has to extend into the search environment and will interrupt, albeit in only a very small way perhaps, their training and work.

So, how about your dog, the one who’s trying to search in an environment where other, unfamiliar, dogs are part of the audience? Well, unsurprisingly perhaps, in Mariti et als (2017) study, calming signals were found to be used by dogs “more frequently while interacting with unfamiliar dogs”. In other words, your dog, if he’s to feel safe, will have to expend considerable amounts of energy monitoring (and responding to) the other, unfamiliar dogs’ apparent intentions (for good or bad) in preference to Scent Detecting.

As Palagi et al (2015) point out, it’s “probably adaptive for animals to discriminate others’ emotional expressions because this allows them to anticipate the behavioural response of the observed individual and to adjust their own behaviour accordingly”. It’s also worth considering here that, as Nielsen et al (2015) warn, “odors from animals in distress have an impact on conspecifics … [with the spreading of] … negative states”. This view is supported by Siniscalchi et al (2018) who state that “when a dog experiences an emotional state, for example anxiety, it releases a specific body odour into the environment. Despite being involuntary, this signal is received as a communicative signal by other individual because it informs them about the sender’s inner state and it can produce changes in the receiver’s behaviour”. If there are any dogs in the search environment – perhaps as part of the audience – who are uncomfortable around other dogs or people – fearful, anxious, worried – they will be distressed and your dog will know!

And what about you? A number of handlers have reported that because they don’t have to worry about other dogs in the search area they’ve been able to relax and feel more comfortable. It probably doesn’t need stating but, if you feel “safe” your dog will feel “safe” too. In support of this view, in a study by Custance and Mayer (2012), dogs were found to orientate “toward their owner or a stranger more often when the person was pretending to cry than when they were talking or humming … [this] … response was behaviorally consistent with an expression of empathic concern, but is most parsimoniously interpreted as emotional contagion”. In short … your dog is aware of, and will respond to, your emotions. His Scent Detecting performance will be influenced by how you are feeling. For more information on how you can influence your dog’s performance, you might like to take a look at False Indications, Clever Hans and You

So, what about the oft repeated claims that Scent Detecting can be beneficial in terms of your dog’s behaviour? Well … “Yes” and “No” and “Perhaps” and “Maybe”. Put most simply, there are “theoretical” reasons why Scent Detecting might have a number of beneficial behavioural effects for your dog (I’ll keep that discussion for another Blog) but any behavioural benefits may have more to do with the training methods employed (and there are as many different training methods used in Scent Detecting as there are in other dog sports and activities) rather than olfaction itself. It’s complicated!

All that said, a search area is not the best place to work on your dog’s social skills … he’s learning how to Scent Detect and that means giving him his own working space. As Anderson (2016) points out, “there is still a common expectation that dogs should automatically like, or at least get along with all people and all other dogs. Fearful, shy, or just plain introverted dogs really suffer from this. But even the most extroverted dog still has personal space. We need to learn to respect it”.

Sommer (1959) explains an animal’s “personal space” in terms of “the distance that the organism customarily places between itself and other organisms. The distance may vary from species to species and individual to individual” and, as Hall et al (?) state “contracts and expands depending on several factors” including his emotional and psychological state, his background and the activity that he’s engaged in at any given moment in time. In short, depending on your dog’s breed, past experiences, physical health, personality, familiarity with the environment, mood on a particular day (the list of variables is almost endless), to work successfully, he will require to be afforded more or less “space”.

I train my dogs to follow odour plumes, filaments and tendrils (Furton et al, 2001) back to source (more in a future blog) rather than using “pattern searching” and / or “detailing”. Patterns and Detailing require you to guide your dog around the search area and point out specific areas for him to investigate. Instead, I encourage my dogs to “free search” … to use their natural abilities to locate the target scent source by going in whichever direction the odour plumes, filaments and tendrils lead. To do this … your dog needs space.

More often than not the scent source may be in location X but for your dog to find it he may have to take himself into location Y to pick up any scent filaments and follow them back to source. What if location Y is also where the audience (including dogs) is sitting? How will your dog feel if he has to push through that audience to do his job? How will the audience dogs respond to having their space intruded upon by an unfamiliar dog? I’ll leave it to you to consider the answers to some of these questions.


2. Scent Detecting Considerations

The very early stages of Scent Detecting training involves “familiarising” your dog to the target odour (Hall et al, 2014). It’s about helping your dog form positive associations with the scent. What starts out as a completely irrelevant odour to your dog (or Neutral Stimulus – NS), will, after “conditioning”, start to predict that good things (food) will follow. In short, your dog starts to develop a strong liking for the odour. Here lies the first potential scent related problem.

If “familiarization” is conducted in an environment where your dog is feeling anxious or worried, perhaps because of the proximity of other unfamiliar dogs, this process is likely to be compromised. It’s certainly worth bearing in mind that “the olfactory system has direct anatomical and phylogenetic linkages to the limbic system, making it the sensory system most closely related to the parts of the brain that seem to mediate emotion” (Wrzesniewski et al, 1999) with a number of studies indicating that “odours present at the time of an event can be encoded in parallel with event details and consequently be used as cues in the retrieval of those event details” (Hughes, 2004). Rather than developing a liking for the target odour your dog might be developing far more negative associations.

And now for the second potential problem. By “familiarising” your dog to the target odour you are attempting to develop a positive conditioned emotional response (CER) … the target scent becomes, as Berridge et al (2009) describe it, a “motivational magnet” which has to be approached, often compulsively! This is definitely the attitude that you’ll want to foster in your scent detecting dog. As soon as he becomes aware of it in the environment it’ll be a cue for him to start working … but … and it’s a very BIG but … what if he’s not the dog whose turn it is to work? What if you have him beside you in the audience? You’ll have spent considerable amounts of time and energy turning what was an irrelevant odour into something that cues him to work and now you’re trying to prevent him working because he’s part of an audience. This has the potential to detract from all the training you’ve put in. Hopefully you’re now starting to see why keeping your dog with you in a search area, when it’s not his turn to work, is a very bad idea!

And finally, the human element of this discussion. I limit any audience to handlers only. If a dog demonstrates any difficulties working around people then the audience is asked to leave the search area until the dog has finished working. This is really no different to my rule that no dog works with other dogs present. In terms of people and what effect they might have on scent, it’s worth considering that every time you move around the search area you’re disturbing the air flow and, with it, scent molecules (Angle et al, 2016). This may, or may not, add to the complexity of the search for your dog but, as your dog’s handler, I ask that you give your dog plenty of space to work and as an audience I ask that you stay seated at all times.

So next time you attend any Scent Detecting event, will you work your dog with other dogs present? Will you let your dog be part of an audience? I’m hoping that you might just give it a little more thought.


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 work. Happy reading.


© Lesley McAllister – Scent : Detect : Find Ltd 2018

www.scentdetectfind.co.uk


References / Further Reading

1. Angle C, Waggoner LP, Ferrando A, Haney P and Passler T (2016) Canine Detection of the Volatilome: A Review of Implications for Pathogen and Disease Detection. Frontiers in Veterinary Science. June. Vol 3. 47. 1-7.

2. Anderson E (2016) Space Invaders. Barks from the Guild. Issue 21. Nov. 18-25.

3. Berridge KC, Robinson TE and Aldridge JW (2009) Dissecting components of reward; ‘Liking’, ‘Wanting’ and ‘Learning’. Current Opinion in Pharmacology. Feb 9(1). 65-73.

4. Custance D and Mayer J (2012) Empathic-like responding by domestic dogs (Canis familiaris) to distress in humans; An exploratory study. Animal Cognition. September. Vol 15. Issue 5. 851-859.

5. Furton KG and Myers LJ (2001) The scientific foundation and efficacy of the use of canines as chemical detectors for explosives. Talanta. 54. 487-500.

6. Hall ET and Hall MR (?) The Sounds of Silence. https://mymission.lamission.edu/userdata/etherism/docs/Sounds%20of%20Silence(1).pdf Accessed: 10.8.2018.

7. Hall NJ, Smith DW, Wynne CDL (2014) Effect of odor preexposure on acquisition of an odor discrimination in dogs. Learning and Behavior. 42. 2. 144-152.

8. Hughes M (2004) Olfaction, Emotion & the Amygdala: arousal-dependent modulation of long-term autobiographical memory and its association with olfaction: beginning to unravel the Proust phenomenon? Impulse. June 1 (1). 1-58.

9. Mariti C, Falaschi C, Zilocchi M, Fatjo J, Sighieri C, Ogi A and Gazzano A (2017) Analysis of the intraspecific visual communication in the domestic dog (Canis familiaris): a pilot study on the case of calming signals. Journal of Veterinary Behavior Clinical Applications and Research. Volume 18. March-April. 49-55.

10. Nielsen BL, Jezierski T, Bolhuis JE, Amo L, Rosell F, Oostindjer M, Christensen JW, McKeegan D, Wells DL and Hepper P (2015) Olfaction: An Overlooked Sensory Modality in Applied Ethology and Animal Welfare. Frontiers in Veterinary Science. December. Vol 2. Article 69.

11. Palagi E, Nicotra V, Cordoni G (2015) Rapid mimicry and emotional contagion in domestic dogs. Royal Society Open Science. 2. 150505.

12. Rugaas T (2006) On Talking Terms with Dogs: Calming Signals. 2nd Ed. Washington: Dogwise Publishing.

13. Siniscalchi M, d’Ingeo S, Minunno M and Quaranta A (2018) Communications in Dogs. Animals. 8. 131.

14. Sommer R (1959) Studies in Personal Space. Sociometry. 22. 247-260.

15. Wrzesniewski A, McCauley C and Rozin P (1999) Odor and Affect: Individual Differences in the Impact of Odor on Liking for Places, Things and People. Chemical Senses. 24. 713-721.

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.
Panting I
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.
Panting - II.jpg
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.
Panting - III.jpg
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

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