Sep 062012
 

I was recently asked to do a question and answer session for the Facebook group Equitation Science (http://www.facebook.com/groups/equitationscience/). The questions asked were very interesting so I thought I would do an article including some of the Q and A session. I would like to note that there were many fantastic comments made by the other members of the group leading to some great discussion. These comments haven’t been included here for reasons of anonymity and credit, should you wish to read these discussions simply request membership to the group.

QUESTION 1 – Negative reinforcement and avoidance learning.

In horse training, negative reinforcement involves moving away from pressure or in essence avoidance learning. When a horse has a strong disposition towards a flight response or is inclined to quickly move away from threatening stimuli, what training methods are most effective and what research is there to support their efficacy?

Answer – Firstly in this situation I would ask – why is the horse exhibit such a large stress response to the presence of such stimuli? Is the disposition really a personality trait innate to the horse or is the sensitised stress response indicative of the horse manifesting a higher base level of stress or is the response learnt? If the stress level of the horse is higher than ideal even at rest (this could be tested by heart rate or salivary cortisol) the the horses environment needs to be adapted to lower the horse’s base stress level. If the horse’s stress level is higher than it should be this will likely present itself in greater stress reactions to stimuli; this is because the threshold for such a reaction is closer to baseline level of stress in the horse. Isolation of the environmental stress will require some work but, again, analysing whether the horse has access to forage, friends and freedom is a good place to start.

Secondly, if the response is learnt training the horse using positive reinforcement methods will help reduce the stress response. Targeting could be used to train the desired behaviour and put it on a cue, subsequently a secondary cue of a very gentle pressure cue, such the horse would not try to escape it, could then be added if required. Such a training strategy would eliminate the need for stressful aversive stimuli through the use negative reinforcement training but would allow a gentle pressure cue if needed. If the horse has become more generally fearful of an environment/object/situation, rather than just the stimuli used to implement negative reinforcement, counter conditioning stimuli associated with fear will be helpful. Desensitisation could also be used to reduce the stress experienced by the horse through not over facing the horse with them the stimuli they are fearful of.

Evidence for positive reinforcement methods:

http://www.ingentaconnect.com/content/ufaw/aw/2007/00000016/00000004/art00007

http://www.sciencedirect.com/science/article/pii/S0168159107002869

http://www.springerlink.com/content/4122111x7620v040/

http://www.sciencedirect.com/science/article/pii/S0003347209006034

One for targeting: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1284337/

http://onlinelibrary.wiley.com/doi/10.2746/042516406778400574/abstract

Additional comment – In this case we were examining a horse with a large stress response to negative reinforcement stimuli and thus would require training to eliminate this response to pressure (or the stimuli used for negative reinforcement). Although I believe we can use very gentle negative reinforcement without too much stress to the horse, you raise an interesting point because unfortunately positive punishment (the addition of an unpleasant stimulus to lower the likelihood of a behaviour reoccurring) has to of occurred in order that the stimulus can be removed for negative reinforcement. If the stimulus did not start it could not be removed. The two concepts, although distinct, are not mutually exclusive, they work in tandem (see http://www.theequineindependent.com/home/?p=103).

QUESTION 2 – Equine Learned Helplessness

The American psychologist Martin Seligman published most of the early work on learned helplessness. This is the technical term used to describe a condition in which a human/animal has learned to behave helplessly, failing to respond even when there is an opportunity for it to help itself by avoiding unpleasant circumstances or gain a positive reward. In people, learned helplessness is associated with depression and other mental health problems. I am just wondering what the possible epidemiology of equine learned helplessness might be, the “symptomatology” and possible health ramifications.

Answer – Learned Helplessness is a psychological phenomenon which occurs when an animal, be it horse or human, no longer tries to escape an aversive stimulus (or in some cases multiple aversive stimuli). Such behaviour usually manifests because the horse has repeatedly been exposed to an aversive stimulus, tried to escape it, and failed. Eventually the animal stops trying to escape and thus behaves in a helpless manner. Often the horse may only exhibit this behaviour to one or two stimuli, however, sometimes you can see this helplessness response generalise in the same manner as other behaviours may generalise. Therefore, the helplessness may not be stimulus or situation specific. In the horse world sometimes such horses are considered ‘shut down’.

Specifically in horses restraint, pressure and punishments have been considered a potential source of learned helplessness if incorrectly utilised. Examples of potential sources of learned helplessness include the incorrect use of riding gadgets such as draw reins, strong bits (even kinder bits in the wrong hands), spurs, whips … I am sure we can all think of more. Some specific training techniques e.g. leg tying and dare I say Rolkur, rely on learned helplessness, however, any technique that uses aversive stimuli can be at risk of inducing such a response if wrongly applied.

Symptomology:

*The most obvious symptom is a lack of escape behaviour in response to an unpleasant stimulus. The stimulus may be pressure, fear or pain based.
Other symptoms that have not been examined closely in horses but are documented in humans include:
*Sensitised and adapted stress response. If a prolonged period of exposure to an inescapable unpleasant stimulus it experienced, the results can present in the form of both the psychological and physiological symptoms of stress. These may continue if the horse if exposed to stimuli associated with the inescapable stressor, even if the stressor itself is no longer present.

*Psychologically the horse may experience anhedonia, lack of motivation, disrupted emotional processing, unusual stress responses (fight and flight) and inhibited learning/cognitive ability.

*Physiologically the horse may experience increase stress, a reduced immune response and an increased risk of the disorders associated with a high stress environment and life experience (e.g. stomach ulcers). It is possible that these symptoms could all occur in the horse although I stress little specific research has been done in this area, and given that most learned helplessness studies on animals were not entirely ethical this may not be a terrible thing.

There are theories of depression which concentrate on the role of learned helplessness, however these are widely debated, certainly there is a cross over in both symptomology and neurological activation if you are interested in reading about any of the above a quick google search will find you a lot of information.

Specifically with regards to horses I can recommend the paper – “Is There Evidence of Learned Helplessness in Horses?” Hall et al, 2008.

Neurology :

I don’t have time to write out all the neurological information so you will have to forgive me quoting.

“Evidence suggests an important role for 5-HT neurons in the dorsal raphe nucleus (DRN) in mediating learned helplessness (see Maier and Watkins 2005, for reviews). The DRN is a midline brainstem structure that contains a high concentration of 5-HT neurons that provide 5-HT to higher brain centers via multiple fiber tracts. …5-HT neurons in the DRN have long been associated with depression … anxiety …and behavioral responses to stress… The DRN projects to structures involved in fear, anxiety, and depression, such as the cortex, amygdala, periaqueductal grey (PAG), and locus coeruleus (LC)” Greenwood and Fleshner (2008). You can see that stress can affect the functioning of these pathway.

Rehabilitating the learned helplessness horse:

Here are a few idea for undoing the learned response, remember the brain is plastic even when the horse is old and thus often the horse can relearn/unlearn their response to stimuli.

*It’s cliché but time is a great healer, especially time in a stress free environment where they no longer experience the stressor which induces the learned helplessness response. Ideally the horse will be out as much as possible, be eating for 16hrs-ish a day and have a stable peer group to socialise with. The old adage of forage, friends and freedom can go a long way towards the rehab of any horse. The brains stress response will often (but not always) ‘reset’, if you like, in such an environment making further training much easier. Removing the stressor(s) is the first step!

*If the stressor is something which the horse has to come into contact with in their environment, a training strategy including counter conditioning and desensitisation combined will help the horse to relearn to be relaxed and even enjoy the presence of the previously stressful object/environment. Obviously you would only do this for objects and situations associated with the aversive events/helplessness and not the events themselves! For example, if the horse had become helpless when ridden you could work on encouraging the horse to enjoy being ridden by training without the use of large aversive stimuli but instead with positive reinforcement. I have found that reward inhibits stress in the horse. Indeed research shows that activation of the reward pathways of the brain actively dampens stress responses and therefore will help the horse to be without a heightened stress response and the psychological and physiological manifestations of increased stress.

Additional comment – Grass is included in the forage part of the phrase. The phrase is applicable to the horse as a management system as it describes the most prominent innate needs of the horse in order that they can be without stress. Therefore, as you say, it is necessary at all stages of the horse’s life. I was describing it as part of the rehabilitation for learned helplessness because I suspect that none here would drive a horse into learned helplessness but they may acquire such a horse or be called out to one. A slightly more complex version of the same paradigm might be an adapted version of Maslow’s heirarchy of needs. Regarding the relationship between submission and learned helplessness it would certainly be valid to suggest a behavioural parallel between the two psychological states (unfortunately, I don’t own the Equid Ethogram). Possibly it would be accurate to say that all learned helplessness could be described as submission but not all submission is learned helplessness, of course this depends on your definition of submission. The relationship between these two psychological concepts seems to be complex and their isn’t a huge amount of research available, however, this paper is worth a read (again I don’t agree with the methods used) http://www.ncbi.nlm.nih.gov/pubmed/17708544. Hope this answers your question.

QUESTION 3 – There seems to be a lot of confusion out there with regards to definitions of negative punishment (response cost, time out). Do you think horses actually understand negative punishment ? What research has been done in this area?

Answer – Negative punishment is possibly the trickiest of the four primary learning theory concepts to apply well to horse training. The removal of a desirable stimulus in consequence to an unwanted behaviour in order to punish said behaviour requires both timing and an understanding of frustration/defensive behaviours. Obviously, removing a highly desirable stimuli from the horse could trigger unwanted behaviours over and above the original unwanted behaviour, so care is needed. For example, removing food from a horse with food related issues may trigger defensive aggression, but this technique may not unduly stress another horse, therefore each horse and behaviour needs to be considered with regards to their individual personality. So yes horses can be trained with negative punishment, it’s the human understanding of punishment and the side effects which can occur when such methods are used which is key. Rewarding a incompatible behaviour in place of the unwanted behaviour may be an effective alternative technique, circumventing the need for punishment.

Research in this area is thin on the ground, probably because the ethics of such research would be hard to navigate, similarly to work on positive punishment.

Additional related question – So when I am clicker training my horse and withhold food whilst I am waiting for the correct response, is this negative punishment? As I have not actually taken anything away, rather I am withholding a positive reinforcer?

Answer – This is a tricky question, if positive reinforcement is being used the reward should never be given to the horse and then removed creating negative punishment. However, sometimes this is case when the trainer is not sure whether to reward or not, so the trainer needs to be definite with the timing. The trainer also needs to be aware that if the horse is too hungry or gets anxious regarding food negative reinforcement could also come into play as the food removes briefly the aversive stimuli of hunger(interestingly there are theories of drug addiction which focus on the role of negative reinforcement). These effects can be reasonably simply averted by observing the horse for signs of stress or learning disruption which might suggest their role and changing strategy to ensure the positive reinforcement acts exclusively.

Additional comments –

The training strategy should be defined before it occurs however, within the training observation and evaluation should be regularly considered to ensure that the trainer is training in the manner they intend and that the horse is happy and progressing in said training.

To clarify the negative punishment with food stimuli does not occur simply by the presence of food because you have not removed anything from the horse, the horse never had the food. It would only occur, as I said before, if the trainer was ambiguous in timing and gave the horse the food and then removed it due to a change of mind.

If you have a question about any of the answers or the terminology used, please feel free to leave a comment or email me and I will happily answer your questions.

Emma Lethbridge

(Emma@theequineindependent.com or E.M.Lethbridge@shu.ac.uk)

Jul 012012
 

Welcome to my round up of some of the latest releases in equine science. These scientific equine papers have provided some interesting information sure to spark debate and inform our equine management and training practises; including a most important paper which provides evidence that horses ridden in hyperflexion may experience difficulty breathing because of airway obstruction.

Factors in Horse Training

Does learning performance in horses relate to fearfulness, baseline stress hormone, and social rank?

By Janne Winther, Line Christensen Peerstrup Ahrendt, Randi Lintrup, Charlotte Gaillard, Rupert Palme, Jens Malmkvist

“The ability of horses to learn and remember new tasks is fundamentally important for their use by humans. Fearfulness may, however, interfere with learning, because stimuli in the environment can overshadow signals from the rider or handler. In addition, prolonged high levels of stress hormones can affect neurons within the hippocampus; a brain region central to learning and memory. In a series of experiments, we aimed to investigate the link between performance in two learning tests, the baseline level of stress hormones, measured as faecal cortisol metabolites (FCM), fearfulness, and social rank. Twenty-five geldings (2 or 3 years old) pastured in one group were included in the study. The learning tests were performed by professional trainers and included a number of predefined stages during which the horses were gradually trained to perform exercises, using either negative (NR) or positive reinforcement (PR). Each of the learning tests lasted 3 days; 7min/horse/day. The NR test was repeated in a novel environment. Performance, measured as final stage in the training programme, and heart rate (HR) were recorded. Faeces were collected on four separate days where the horses had been undisturbed at pasture for 48h. Social rank was determined through observations of social interactions during feeding. The fear test was a novel object test during which behaviour and HR were recorded.

Performance in the NR and PR learning tests did not correlate. In the NR test, there was a significant, negative correlation between performance and HR in the novel environment (rS=−0.66, P<0.001, i.e. nervous horses had reduced performance), whereas there was no such correlation in the home environment (both NR and PR). Behavioural reactions in the fear test correlated significantly with performance in the NR test in the novel environment (e.g. object alertness and final stage: rS=−0.43, P=0.04), suggesting that performance under unfamiliar, stressful conditions may be predicted by behavioural responses in a fear test. There was a negative correlation between social rank and baseline stress hormones (rS=−0.43, P=0.04), i.e. high rank corresponded to low FCM concentrations, whereas neither rank nor FCM correlated with fearfulness or learning performance. We conclude that performance under stressful conditions is affected by activation of the sympathetic nervous system during training and related to behavioural responses in a standardised fear test. Learning performance in the home environment, however, appears unrelated to fearfulness, social rank and baseline FCM levels.”

http://www.journals.elsevierhealth.com/periodicals/applan/article/S0168-1591(12)00168-2/abstract

Equine Welfare

Effect of head and neck position on intrathoracic pressure and arterial blood gas values in Dutch Warmblood riding horses during moderate exercise.

By Sleutjens J, Smiet E, van Weeren R, van der Kolk J, Back W, Wijnberg ID.

“OBJECTIVE:To evaluate the effect of various head and neck positions on intrathoracic pressure and arterial oxygenation during exercise in horses.

ANIMALS:7 healthy Dutch Warmblood riding horses.

PROCEDURES:The horses were evaluated with the head and neck in the following predefined positions: position 1, free and unrestrained; position 2, neck raised with the bridge of the nose aligned vertically; position 4, neck lowered and extremely flexed with the nose pointing toward the pectoral muscles; position 5, neck raised and extended with the bridge of the nose in front of a vertical line perpendicular to the ground surface; and position 7, neck lowered and flexed with the nose pointing towards the carpus. The standard exercise protocol consisted of trotting for 10 minutes, cantering for 4 minutes, trotting again for 5 minutes, and walking for 5 minutes. An esophageal balloon catheter was used to indirectly measure intrathoracic pressure. Arterial blood samples were obtained for measurement of Pao(2), Paco(2), and arterial oxygen saturation.

RESULTS:Compared with when horses were in the unrestrained position, inspiratory intrathoracic pressure became more negative during the first trot (all positions), canter and second trot (position 4), and walk (positions 4 and 5). Compared with when horses were in position 1, intrathoracic pressure difference increased in positions 4, 2, 7, and 5; Pao(2) increased in position 5; and arterial oxygen saturation increased in positions 4 and 7.

CONCLUSIONS AND CLINICAL RELEVANCE:Position 4 was particularly influential on intrathoracic pressure during exercise in horses. The effects detected may have been caused by a dynamic upper airway obstruction and may be more profound in horses with upper airway disease.”

http://www.ncbi.nlm.nih.gov/pubmed/22452499

More information on the above paper can be found at http://www.thehorse.com/ViewArticle.aspx?ID=20201

On the significance of adult play: what does social play tell us about adult horse welfare?

By Martine Hausberger, Carole Fureix, Marie Bourjade, Sabine Wessel-Robert and Marie-Annick Richard-Yris

“Play remains a mystery and adult play even more so. More typical of young stages in healthy individuals, it occurs rarely at adult stages but then more often in captive/domestic animals, which can imply spatial, social and/or feeding deprivations or restrictions that are challenging to welfare, than in animals living in natural conditions. Here, we tested the hypothesis that adult play may reflect altered welfare states and chronic stress in horses, in which, as in several species, play rarely occurs at adult stages in natural conditions. We observed the behaviour (in particular, social play) of riding school horses during occasional outings in a paddock and measured several stress indicators when these horses were in their individual home boxes. Our results revealed that (1) the number of horses and rates of adult play appeared very high compared to field report data and (2) most stress indicators measured differed between ‘players’ and ‘non-players’, revealing that most ‘playful’ animals were suffering from more chronic stress than ‘non-playful’ horses. Frequency of play behaviour correlated with a score of chronic stress. This first discovery of a relationship between adult play and altered welfare opens new lines of research that certainly deserves comparative studies in a variety of species.”

http://www.springerlink.com/content/a773802p37590541/

Training the Ridden Horse

Horse walker use in dressage horses

By T.J. Walker, S.N. Collins and R.C. Murray

“Horse walkers have become popular in the modern exercise regime for dressage horses, however recent investigations of injury risk factors have indicated a significant association between horse walker use and lameness. A detailed telephone questionnaire was conducted to document horse walker usage and assess whether horse walker use could predispose dressage horses to lameness. Information on horse walker features and use, and individual horse lameness history was recorded. Chi-squared tests were performed to identify horse walker variables associated with lameness. Although analyses failed to establish a direct link between lameness and any specific horse walker feature, the high proportion of lame horses in this study suggests that there is an underlying and, as yet, unidentified cause of lameness related to horse walker usage.”

http://wageningenacademic.metapress.com/content/j3q3511435340324/

The effect of double bridles and jaw-clamping crank nosebands on temperature of eyes and facial skin of horses

By Paul McGreevy, Amanda Warren-Smith and Yann Guisard

“Any apparatus that restricts a horse’s movement can compromise welfare. Eye temperature as measured remotely using infrared thermography is emerging as a correlate of salivary cortisol concentrations in horses. This article explores the effect on the temperature of the eyes and facial skin of horses wearing devices that restrict jaw movements. In certain equestrian disciplines, unacceptable equine oral activity, such as gaping of the mouth, is penalized because it reflects poor training and lack of compliance. This explains the wide range of nosebands and flash straps designed to prevent the mouth opening. Some of these nosebands are banned from higher-level dressage competitions in which double bridles are mandatory, possibly because they are regarded as restrictive. Nevertheless, the current international rules overlook the possibility that noseband can appear innocuous even though some designs, such as the so-called crank noseband, can be ratcheted shut to clamp the jaws together. Some equestrian manuals and competition rule books propose that “two-fingers” be used as a spacer to guard against overtightening of nosebands but fail to specify where this gauge should be applied. The vagueness of this directive prompted us to undertake a small random survey of the finger dimensions of adult men (n = 10) and women (n = 10). There were significant sex differences in the measurements of fingers of adults (P < 0.001), thus illustrating that the “two-finger rule” is not a reliable guide for standardized noseband fastening. Infrared thermography was used to measure the temperature of facial skin and eyes of adult horses (n = 5) wearing a double bridle with and without a cavesson noseband.

A taper gauge was developed based on the mean circumference of adult index and middle fingers (9.89 ± 0.21 cm), and this was used as a spacer at the nasal planum or beside the mandible when tightening the noseband. The nosebands were fastened significantly tighter when the taper gauge was used beside the mandible than at the nasal planum (P = 0.02). Wearing double bridles and nosebands that had been tightened with and without the taper gauge caused an increase in eye temperature compared with baseline values (P = 0.012), and the tighter the noseband was fastened, the cooler the facial skin of the horse (and, presumably, the greater the impairment of vascular perfusion) when compared with baseline values (P = 0.016). This study suggests that horses wearing double bridles and tight nosebands undergo a physiological stress response and may have compromised vascular perfusion. Consequently, on welfare grounds, the use of nosebands that cause any constriction of jaw movement should be reviewed as soon as possible.”

http://www.journalvetbehavior.com/article/S1558-7878(11)00143-2/abstract

Pilot study of behavior responses in young riding horses using 2 methods of making transitions from trot to walk

By Agneta Egenvalla, Marie Eisersiöb and Lars Roepstorffc

“According to the principles of negative reinforcement, when an aid has been given to an animal, it should be released as soon as the desired response has been achieved, and, if performed well, may be associated with fewer conflict behaviors than otherwise. In riding, pressure in the horse’s mouth from the bit is used to give signals to the horse, and both rein tension and patterns of releasing this tension will vary. The aim of this pilot study was to study horse behavior during 2 different methodologies used to shape relatively naïve horses to a deceleration signal while making downward transitions from trot to walk. Method 1 involved relief from rein tension at the first attempt to perform a correct response (M1), and method 2 entailed that rein tension was relieved at the completed correct response (M2). Four horses were ridden by 4 riders over 4 days (1 rider each day), and each horse made 10 transitions each day for each method, which produced 320 transitions. Rein tension was recorded, and horse behavior and rider signal behaviors were evaluated from video recordings. Horse behavior was divided into the following 3 different categories: “pushing against the bit,” “moving away from the bit,” and “decelerating.” Linear models were constructed tracking the percent of the transition time that horses demonstrated at least 1 behavior in the “pushing against the bit,” “moving away from the bit,” and “decelerating” categories, and with random effects for rider, horse, and transition number nested within horse. Fixed effects analyzed were the methods, proportion of the transition time above 30 N for each rein, and the rider signal behaviors. M1 and M2 had on average 19% (standard deviation: 16) and 38% (standard deviation: 23) of the time with >30 N per rein, respectively. In the models for the “pushing against the bit” behaviors, M2 increased rein tension and “exerting pressure on the reins” increased the level of these behaviors. “Releasing pressure” interacted with “pulling back on the reins”; this combination was associated with an increased level of “pushing against the bit” behaviors. The “decelerating” behavior was associated with lower rein tension. In the “decelerating” behavior models, “pulling back on the reins” led to decreased “decelerating” behavior, whereas “still hand” and “releasing pressure” led to increased “decelerating” behavior; however, the interaction “pulling back on the reins” and “releasing pressure” led to decreased “decelerating” behavior. “Moving away from the bit” had no significant determinants. We concluded that fewer “pushing against the bit” behaviors were created by M1 and that a lower rein tension was associated with the “decelerating” behavior. Reinforcing the horse’s attempts, to assist in finding the correct response, benefits the welfare of the horse, and importance of a light hand should be continuously emphasized during riding education.”

http://www.sciencedirect.com/science/article/pii/S1558787811001481

Equipment and training risk factors associated with ridden behaviour problems in UK leisure horses

By Jo Hockenhull and Emma Creighton

“Ridden behaviour problems are prevalent in the UK leisure horse population and may have implications for horse welfare and rider safety. This study aimed to identify risk factors associated with ridden behaviour problems in UK leisure horses from the training approaches and equipment used with them. An Internet survey was used to collect data on 1326 horses from a convenience sample of leisure horse owners. The survey asked owners to report the frequency their horses displayed fifteen ridden behaviour problems over the previous week. Data on the frequency of occurrence of behaviour in four components of related ridden behaviour problems were explored for association with details of the horse’s working life, including the type of tack, equipment and training used, and the frequency the professional services of saddlers and farriers were employed using logistic regression analyses. Behaviour data were generated for 791 individual horses. Risk factors associated with the ridden behaviour problems emerged as three themes. One related to the design and fit of the saddle, with dressage and working hunter saddles associated with a reduced risk of ridden behaviour problems compared to general purpose saddles. The horse’s footcare and shoeing regime was associated with three of the four groups of behaviour problems. An extended interval (seven weeks or more) between farrier visits was associated with an increased risk of discomfort behaviour. Taking an outcome-centred approach to training, for example through the use of artificial training aids, was associated with an increased risk of behaviour problems while spending more time with the horse outside of training situations, a more horse-centred approach, was associated with a reduced risk of problems. Further research is required to understand the causal relationships behind these associations, with the aim of improving the welfare of the horse and the well-being and safety of its rider.”

http://www.journals.elsevierhealth.com/periodicals/applan/article/S0168-1591(12)00020-2/abstract

I hope you enjoy this collection of abstracts as much as I did. If you have a question about any of the abstracts or the terminology used, please feel free to leave a comment or email me and I will happily answer your questions.

Emma Lethbridge

(Emma@theequineindependent.com or E.M.Lethbridge@shu.ac.uk)