Tag: Detecting

Scent Detecting and the “White Dog” – Does she serve any useful purpose?

What is a “White Dog”?

Let me start by stating that, within Scent Detecting circles, any reference to a white dog has absolutely nothing to do with her coat colour. The dog may be white … but, equally, she could be black or brown or brindle or red. Her actual coat colour is completely irrelevant.

Instead, a white dog is a term used almost exclusively within the world of competitive Scent Detecting to denote an experienced Scent Detecting dog who is tasked with searching an area prior to the start of a competition. The presumption seems to be that if the white dog can successfully complete the search then it follows that it will be a fair test for all dogs competing in this same area, with the same hides, at some later point in time.  

But is this really so? 

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Scent Detecting Competitions as a form of Assessment

A Scent Detecting competition is a form of assessment. It’s an examination. It’s a test. It’s a one-off event. It’s “a means of collecting data to demonstrate [that] an acceptable standard … has been reached” (Hand, 2006).

To this end, there’s an expectation that the competition Judge, guided by his or her particular competitive organisation’s regulations, will set “appropriate tasks” (Hernandez, 2012) for all competitors working at a particular level of expertise. The use of a white dog prior to the start of a competitive event is supposed to confirm that this is the case – the searches are appropriate and the competition fair. 

But, how can you be sure that “appropriate tasks” have been set for you and your dog? What actually constitutes a fair test of your dog’s abilities? How might you recognise a quality assessment process? Does the use of a white dog actually address any of these very understandable concerns? 

Well, according to Brady (2005), for any assessment process to perform its function – provide useful feedback and act as a gatekeeping mechanism to halt further progress until a particular standard has been reached – then it must be valid, reliable, discriminatory and practical. These are referred to as the “Cardinal Criteria” of assessment (Quinn, 2000) and are considered the hallmarks of a quality assessment process.

Validity

Validity refers to the extent to which the assessment process – test or competition – measures what it is intended to measure. It’s about finding the correct measuring tool for the job in hand. For example, if you want to assess the weight of something – how heavy it is – you’d be far better to reach for a set of weighing skills than a tape measure or stop-watch!

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Similarly, if you’re assessing a dog’s Scent Detecting skills – which can encompass an enormous range of attributes – then you’ll need to use the correct measuring instrument.   

One possibility is to use a criterion referenced assessment process where the performance of the competing Scent Detecting dog and handler can be measured against a pre-determined set of criteria, or standards, that are considered to reflect the necessary qualities, skills and attributes of a reliable Scent Detecting team.

Searches and hides are planned to reflect the criteria set out within the criterion referenced assessment document. The competing dog and handler will then either achieve these criteria, partially achieve these criteria or fail to achieve some or all of the criteria. 

Working a white dog prior to the start of a competitive Scent Detecting event will do little to strengthen the validity of the assessment process and here’s why – 

  1. By it’s very definition, a white dog (and her handler) will be an experienced Scent Detecting team.
  2. The competition may be specifically for those Scent Detecting teams with far less experience than the white dog and her handler. 
  3. As an experienced team, if the white dog and her handler successfully complete the planned searches, this provides NO information as to the appropriateness (validity) of the searches for the less experienced competitors that will follow on.
  4. All that can be concluded from this exercise is that the white dog and her handler were able to successfully complete the searches at that particular moment in time.
  5. The white dog and her handler have not been able to validate the criteria used to plan the searches and hides. They have been unable to provide evidence that the competition actually measures what it is intending to measure. ie; the Scent Detecting qualities, skills and attributes of a less experienced Scent Detecting team.

Ultimately, when it comes to ensuring the validity of any assessment process – test or competition – the responsibility for setting appropriate searches must lie with the Judge and their particular competitive organisation rather than with the white dog and her handler.

Reliability  

The reliability of any assessment process is concerned with the consistency of results. Put simply, would different competition Judges, using the same assessment criteria, agree on the quality of performance of a particular Scent Detecting dog and handler team? Would they award the same, or similar, marks? If so, then the assessment process would be considered reliable. The Judges have both interpreted, and applied, the assessment criteria in a similar fashion.

An assessment’s reliability can be strengthened by the construction of carefully expressed criteria, ones that are less vulnerable to individual interpretation by the competition Judge. As White (1986) states, if you want to form a clear, unambiguous picture of an individual’s progress it’s important to focus on concrete, directly observable behaviour. Carefully expressed criteria can help you do just that.

Clearly, the use of a white dog immediately prior to the start of any Scent Detecting competition can do nothing to strengthen the reliability of the assessment process. Increasing the reliability can only be achieved during the early planning stages, when criteria are first being considered.

And that’s precisely where a white dog might be helpful – during the initial writing of criteria – long before any competition takes place. If a group of Judges, using a set of proposed criteria, can agree on a white dog’s performance then this could demonstrate a reasonable degree of reliability in the assessment process.  

Discriminatory Powers

Discrimination is the ability of the assessment process to differentiate between varying levels of ability. Assessment processes need to be able to discriminate between those Scent Detecting teams that have reached the required standard and those who have not. Assessment processes, including competitive events, should not be so difficult that all Scent Detecting teams are likely to fail or so easy that all are likely to pass.

To be clear, the ability of an assessment process to discriminate between levels of achievement is considered a good thing. Gate-keeping is an important feature of any assessment process.

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But how does the use of a white dog and handler team help here? How does a white dog successfully completing one or more searches prior to a competition ensure that the assessment process will discriminate between levels of ability in the dogs that will be competing later? 

As discussed earlier, the presumption seems to be that if the white dog can successfully complete the search then it will be a fair test for all dogs competing in this same area, with the same hides, at some later point in time. If this were the case then there would be an expectation that all competing dogs would be as successful as the white dog. In other words, the competition has failed to discriminate between competitors. The white dog has served no useful purpose.

Practicality

Assessment processes should be practical to implement in terms of financial costs, time and ease of administration. If the assessment process is not practical then this will impact all of the other cardinal criteria as corners are cut and / or assessment criteria incorrectly applied. 

Many competitive organisations do not insist on the use of a white dog prior to the start of a Scent Detecting competition. There may be no suitably experienced dog available, and time may be short. The use of a white dog may not be practical.

Now the question must be, if a white dog is not mandatory for all Scent Detecting competitions, what possible justification is there for using one at any competition?  

And now for some common sense!

  1. A white dog, by definition, refers to an experienced dog and handler team.
  2. By definition, an experienced dog and handler team should be able to out-perform less experienced competing teams.
  3. A white dog that successfully completes all searches prior to the start of a competitive event can provide only limited information about the appropriateness of the planned searches. 
  4. The information provided by the white dog is simply that that dog, at that moment in time, working under those particular conditions has successfully completed the searches. It provides no useful information on the appropriateness of the planned searches for any competing teams that will be following on. 
  5. All competing dogs, working at later points in time, will be subject to markedly different conditions to those experienced by the white dog. Changes in temperature, air and wind movement. Contamination of the search area by the target odour and odours from other dogs, handlers and officials. The white dog’s earlier success may simply have been as a result of working at the time she did and under the prevailing conditions at that time. This  goes some way to explaining why many competitive organisations will use a draw system to allocate the running order for competitors.
  6. Every dog is a thinking, feeling, individual. The use of a white dog cannot address the individuality of every Scent Detecting team. Far better to set clear criteria at an organisational level, that reflect performance expectations for different levels of experience, than rely on a white dog to decide whether particular searches are appropriate for a particular competition.

 

In conclusion …

Assessment is central to the learning process. It’s important that we get it right. The use of the white dog in competition settings does little, if anything, to strengthen the assessment process and as such cannot support the future learning of competing Scent Detecting teams. Instead, all that the white dog may do is lull the competition Judge into a false sense of security, allowing them to believe that they’ve set a fair assessment for all competing dogs. This may well be far from the case.

 

Final Note

As with all 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 represent an accurate reflection of the author’s original work. Happy reading.

© Lesley McAllister – Scent : Detect : Find Ltd 2021

www.scentdetectfind.co.uk

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

References / Further Reading

  1. Brady A (2005) Assessment of learning with multiple-choice questions. Nurse Education in Practice. 5. 238-242
  2. Hand H (2006) Assessment of learning in clinical practice. Nursing Standard. 21.4 48-56
  3. Hernandez R (2012) Does continuous assessment in higher education support student learning? Higher Education. 64. 489-502
  4. Quinn FM (2000) The Principles and Practice of Nurse Education. 4th Ed. Cheltenham: Stanley Thorne (Publishers) Ltd
  5. White OR (1986) Precision Teaching – Precision Learning. Exceptional Children. Special Issue: In search of excellence: Instruction that works in special education classrooms. 52.6 522-534

 

 

Smoothing out the Lumpy Bits; Why it might be wise to teach the indication before the search and all that back chaining stuff

At its most basic, Scent Detecting requires your dog to search for, and locate, the source of an odour. On this simple description, your dog is engaged in Scent Detecting activities (entirely independent of you) for a very large portion of his day; finding a dropped crumb of food on the floor, discovering where a passing rabbit has left some tasty deposits, examining your clothes when you return home at night.

A little bit of independent Scent Detecting.

As Horowitz et al (2014) point out, your dog’s Umwelt or “Self-World” is primarily olfactory; “Dog noses house hundreds of millions more olfactory cells than humans’ do, and their corresponding brain regions are much more developed relative to their visual areas than in humans“.

So, what differentiates your dog’s independent Scent Detecting activities from those that involve you, his handler?

One word … Training. 

Well, two actually … Careful training. 

Ok, three … Careful, thorough, training!

Careful, thorough, training

Given your dog’s natural Scent Detecting talents, it can be hugely tempting to simply let him ‘get on with it‘. Spend a few minutes browsing any social media platform and you’ll soon find plenty of examples of this laissez-faire approach to Scent Detecting training, often with highly questionable results.

Yes, olfaction is your dog’s speciality but he isn’t Lassie! He can’t read your mind, guess what you want or speak your language. If you want him to find a specific odour for you – truffles perhaps – then you need to find some way of harnessing his natural abilities … some way of communicating your particular scent detecting requirements to your dog that might just differ from his own! And this is where careful, thorough, training comes into play.

Splitting vs Lumping

I start by splitting my Scent Detecting training into three separate, but interconnected, phases;

  1. Familiarising my dog to the target odour.
  2. Training the passive indication.
  3. Searching.

By splitting I am referring to the process of dividing the whole training task – in this case, Scent Detecting – into smaller, more manageable, training elements as opposed to lumping all three elements together and training them as a whole (Berg, 2018. Zerubavel, 1996).

According to Zerubavel (1996), “although the world in which we live is essentially continuous, we experience it as discrete chunks: strangers and acquaintances, fiction and nonfiction … Carving out of reality such ‘islands of meaning’ involves two contrasting yet complementary cognitive acts – lumping and splitting. The former entails grouping ‘similar’ things together in a single mental cluster. The latter involves perceiving ‘different’ clusters as separate from one another“.

In short, splitting makes our world, and our training, more manageable.

Why Split the training?

Well … the simple answer is … I like my Scent Detecting training to progress as smoothly as possible. I don’t like lumps!

I don’t like lumps in my Scent Detecting training!

If, as seems common practice, I were to lump my scent detecting training together and set my dog off to search an area before he’d been familiarised to the target odour and had a trained and reliable indication, how would I manage the following possible outcomes?

  1. He seemed to search the area very well but he didn’t find the target scent source.
  2. He definitely found the target scent but he pulled it out of the box, ran around the room with it in his mouth and chewed it up.
  3. He didn’t move from my side.

How do I let my dog know which bits he did well and were exactly what I could have hoped for and which bits were (to my view) just plain wrong? How can I reward his thorough searching in outcome 1 even though he didn’t actually locate his target scent? How can I reward my dog for locating his target scent in outcome 2 when he then went on to chew it up? And what on earth do I do about outcome 3?

Tricky, isn’t it? …. and this is what lumpy “training” looks like. Messy. Confused. Frustrating. Directionless. Unreliable. If our dogs learn anything from this lumpy approach to training, it would seem to be despite us rather than because of us. In contrast, splitting allows us to work on one specific training element at a time, helping to ensure competence in that area before moving on to another training element and then, eventually, putting all the elements together in one Scent Detecting whole or Lump.

But Splitting the training is so time-consuming, isn’t it?

Well, NO … it isn’t.

Splitting your training into smaller elements allows you to simplify things for your dog, aids clear communication, reduces frustration and increases your chances of getting things right in the first place without the need to add in further, remedial (Sticking Plaster), training at some later point in time.

Splitting your training results in …

  1. easily understood and manageable steps toward a larger end-goal.
  2. tiny bits of behaviour that, when successfully achieved, will allow you to reward your dog immediately.
  3. tiny bits of behaviour that, when things don’t go so well, will allow you to identify and address the problem rapidly with a revised training plan and approach.
  4. no need for your dog to “guess” what is required of him → less frustration → increased likelihood of training success.
  5. no wasted opportunity to reward a well executed behaviour because it’s been lumped together with a whole host of other, poorly executed, behaviours.

When you Split … always keep the Lumps in mind!

Although I’m a big advocate of splitting, it’s worth keeping in mind that there will always be connections between the different phases of training and the overall end goal. In other words, never lose sight of the training lumps! For example, the process of familiarising your dog to the target odour (Hall et al, 2014) acts … believe it or not … as the foundation for later searching!

Splitting … and even more splitting  … 

So, as mentioned earlier, I start by splitting my Scent Detecting training into three separate, but interconnected, phases;

  1. Familiarising my dog to the target odour.
  2. Training the passive indication.
  3. Searching.

… but, my splitting doesn’t end there! Each of these three phases will be split further.

For example, the apparently simple phase of familiarising my dog to the odour – which takes approximately 30 minutes to conclude – is split, again, into the following elements;

  1. Introduction to the environment – Physical and Psychological. If you’d like to know a little bit more about this particular element, follow this link to Scent Detecting and the Enriched Environment
  2. Choice of equipment – Harness and Line.
  3. Rewards – Food vs Toys (play?). Quantity. Timing. Look out for my forthcoming Blog post – Food, Glorious Food.
  4. Selection of the Target Odour – Safety. Cost and Availability. Previous use. Single Odour vs Configural Odour. Quantity (Concentration) of Odour. There’ll be more guidance in my forthcoming Blog post – Selecting a Training Odour for your Scent Detecting Dog. Some Considerations.
  5. Mechanics of Training – Classical (Pavlovian) conditioning. Development of a positive Conditioned Emotional Response (CER).

The devil is, very definitely, in the detail.

… and then there’s Back Chaining

According to Orr (2015), back chaining is a really effective way to build reliable behaviours. It’s a very efficient way to teach a specific behaviour, limits any potential errors and “leads to fluency with less training time” (Pryor, 2012).

Scent Detecting requires a whole series of individual behaviours that, together, form a particular behaviour chain. My dogs’ Scent Detecting behaviour chain looks something like this;

Cue to start work (Context. Harness. Scent in the Environment. Word) → Searching the Area → Locates the Target Scent Source → Passive Indication → Verbal Cue to move away from the scent source → Leaves the Scent Source → Click → Returns to me → Rewards

Your dog’s Scent Detecting behaviour chain may look very different to mine. It all depends on your training approach and your particular requirements … but I’m sure you get the idea; it’s complex and, for success, careful, thorough, training is required.

I teach Scent Detecting by starting at the end of the behaviour chain and working my way back to the beginning. As Orr (2015) states, “by teaching the last part first the learner [my dog] is always moving toward the part of the skill that he learned first and with which he is most confident“. For my dogs, this means learning about the target odour first – the familiarisation process.

Familiarising your dog to the target odour – the mechanics

Familiarising your dog to a specific (target) odour involves Classical, or Pavlovian,  Conditioning. 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 (rewards) will follow (McLeod, 2013).

Familiarisation does not mean leaving the target scent with your dog (amongst his bedding, perhaps) for a few weeks until he becomes “used to”, or “familiar with”, it … unfortunately, “mere exposure [has] no effect on the acquisition of an odor discrimination in dogs” (Hall et al, 2014). If only it were that simple.

Scent : Detect : Find uses a very adapted form of Hall et al’s (2014) familiarisation protocol. Unit 13 is not a laboratory! Firstly, your dog is introduced to his “working” environment – he’s allowed to explore (or not) as he wishes – and then the familiarisation process begins. Over a 20 – 30 minute time-frame, as your dog continues to investigate the environment, he’s given the opportunity to “sniff” the target odour followed, immediately, with food rewards. No other behaviour is required … no need to sit, stand, down or similar. This procedure is repeated approximately 6 – 10 times within the 20 – 30 minute time period.

As for the “sniff” … well … some trainers place huge emphasis on hearing the dog inhale – sniff – during this familiarisation process … nothing less will do. This view probably has its origins in the work of Craven et al (2010) who state that, during normal respiration, approximately 12-13% of inspired air will reach the chemosensory area of the nose – the ethmoturbinate region – and that during active sniffing this may increase by 2-3%.

I’m not worried about hearing your dog sniff. That 12-13% of normally inspired air will do just fine for me! Why? Well let me give you an everyday – olfactory – example. If you walk along a road … breathing normally … you’re likely to become aware of a multitude of different odours, from the smell of bad drains, to the odour of frying chips, to diesel fumes, to … no need to sniff. Interestingly, you’re only going to start sniffing when you encounter a very faint hint of an odour, one that you’re trying to identify and locate. As Mainland and Sobel (2006) state, “when the olfactory system encounters a concentrated odorant, sniff vigor is reduced in real time; when it encounters a diluted odorant, sniff vigor is increased in real time“. In short, as your dog explores the environment, he’ll be aware of the target odour regardless of whether he chooses to sniff or not!

So, back to the familiarisation process and classical conditioning.

Before Conditioning – if your dog is offered food, an unconditioned stimulus (US), he’ll begin to salivate. It’s a physiological process resulting in an unconditioned response (UR). He just can’t help it.

Food (US) —> Salivation (UR)

Initially, if you let your dog smell what will eventually become his target odour, it’ll mean nothing to him. It’s a neutral stimulus (NS).

Target Odour (NS) —> No Salivation

During Conditioning – this requires you to allow your dog to smell the target odour and then provide him with food.

Target Odour (NS) —> Food (US) —> Salivation (UR)

After Conditioning – the target odour is now a conditioned stimulus (CS) and is associated with food. Smelling the odour in his environment will cause your dog to salivate in expectation of food rewards. Salivation in response to the target odour is now a conditioned response (CR).

Target Odour (CS) —> Salivation (CR)

According to Hall et al (2014), familiarising your dog to the target odour in this way enhances odor discrimination training and may reduce the overall training time. In short, it’s a worthwhile exercise to work through especially as it only takes approximately 30 minutes to complete.

Interestingly, and importantly, by classically conditioning your dog to the target odour, it will become what Berridge et al (2009) describe as, a “motivational magnet” – something that has to be approached, often compulsively. This is the foundation of all subsequent searching behaviour. Your dog WANTS to find the target odour. As Berridge et al (2009) explain, WANTING can apply both to unconditioned stimuli (US) such as food as well as conditioned stimuli (CS) such as the target odour after a classical conditioning procedure has taken place such as the one described here.

According to Litman (2005), WANTING involves dopamine activation in the brain and is thought to “motivate approach behaviour and to attribute incentive value to stimuli associated with reward” … the target odour!

But not only will your dog WANT to find the target odour, he’ll LIKE it too. After classical conditioning, your dog will have formed a positive conditioned emotional response (CER) to the target odour. As Litman (2005) states, LIKING involves brain opioid activity and “consequent states of pleasure“. Your dog will LIKE the target odour and WANT to find it. This phenomenon – your dog’s desire to get to the target odour – is sometimes referred to as Scent Obedience.

Familiarising your dog to the target odour and the notion of Imprinting

For clarity, in some scent detecting circles, the process of Familiarising your dog to the target odour (as described here, but often using very different training protocols) is frequently referred to as Imprinting. I prefer to avoid using this term in the context of scent detecting as it has its origins within the field of Ethology and is associated with the work of Konrad Lorenz and the rearing of Geese. Beware, terminology can be confusing and misleading!

and in conclusion …

If you’d like your scent detecting to progress a little more smoothly, consider splitting your training to avoid the lumps. Start where you’d like to finish – Back Chain!

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 represent an accurate reflection of the author’s work. Happy reading.

© Lesley McAllister – Scent : Detect : Find Ltd 2020

www.scentdetectfind.co.uk

References / Further Reading

  1. Berg J (2018) Lumping and splitting. Science. 359. 6382. 1309
  2. 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
  3. Craven BA, Paterson EG and Settles GS (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
  4. Hall NJ, Smith DW, Wynne CDL (2014) Effect of odor preexposure on acquisition of an odor discrimination in dogs. Learning and Behavior. Jan
  5. Horowitz A and Hecht J (2014) Chapter 9. Looking at Dogs: Moving from Anthropocentrism to Canid Umwelt. IN: Horowitz A (2014) Ed. Domestic Dog Cognition and Behavior. The Scientific Study of Canis Familiaris. Springer.
  6. Litman JA (2005) Curiosity and the pleasures of learning: Wanting and liking new information. Cognition and Emotion. 19(6). 793-814
  7. Mainland J and Sobel N (2006) The Sniff is part of the Olfactory Percept. Chem. Senses. 31: 181-196
  8. McLeod S A (2013) Pavlov’s Dogs. http://www.simplypsychology.org/pavlov.html accessed; 22.12.2015
  9. Orr J (2015) Back Chaining: The top secret teaching tool that is the key to professional success. TAGteach International. https://tagteachblog.com/back-chaining-the-top-secret-teaching-tool-that-is-the-key-to-professional-success/ 
  10. Pryor K (2012) Back-Chaining “Retrieve”. Karen Pryor Clicker Training. https://www.clickertraining.com/back-chaining-retrieve Accessed: 3.8.2020
  11. Zerubavel E (1996) Lumping and Splitting: Notes on Social Classification. Sociological Forum. 11.3. 421-423.

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 type 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 a 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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The Passive “nose touch” Indication; a very natural olfactory behaviour

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.

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Brook using her nose to indicate on an invisible target scent

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 or re-training in changed circumstances – Starting off your Scent Detecting training with a pro-active indication may seem like a good idea at the time … until you decide to introduce a new target odour. It may be potentially dangerous to you or your dog or very valuable. Ooops … now may be the time to start afresh with your training, this time with a passive indication.

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 vast 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.

If you are “just a pet dog owner” … keep this in mind … In a study by McCulloch et al (2006), investigating the ability of dogs to detect early- and late-stage lung and breast cancer, it was a mix of pet 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. Those of you who are “just pet dog owners” can, and do, achieve great things with your dogs.

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 a future Blog – one of a series of three – Smoothing out the Lumpy Bits; Why it might be wise to teach the indication before the search and all that back chaining stuff 

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. 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
  6. 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
  7. 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 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