Last revised April 12, 2017
Three-week old donkey.1
It is not my plan to reveal a marvelous new model of horse personality, and I don’t plan on selling DVDs, workbooks, or clinics. But I would like to sketch out a few thoughts here. If you are interested in this stuff, you’ll want to read more about neuropsychology, which I touch on elsewhere.
Humans definitely have personalities. But when we ask psychologists or family or friends what “personality” is, we get different answers. Personality seems to be something we can’t quite define, and the skeptics in the room wonder if we have made something up. Reification is the process in which an idea acquires a reality. We imagine personality, so it must exist. It is only when we set out to measure it that we discover we can’t find it. But that doesn’t lead us to rewinding our reality-producing apparatus. We just keep looking. Reification is one of my favorite words. It just might explain why harder to nail down than it is to nail jelly to a tree.
Horses seem to have personalities, too. But here the thinking and the language becomes even more muddled than when talking about humans.
Pat and Linda Parelli seem to be comfortable talking about “horsenality™”. In their system (which has no apparent basis in the science of horses or other species), all horses differ in two dimensions: extroversion2 — introversion and left brain — right brain.
The extroversion-introversion dimension appears to blend many different qualities. Extroverts, for instance, are quick, but also have a tendency to run. I learned in high school track that being willing to run did not equate to being quick.
All horses have some position on each of these dimensions, creating “four main horsenality™ characteristics”.3
- left-brain extrovert: “This horse is a playful character that needs interesting things to do. He is obsessed with learning and needs variety and new things to keep it fun.”
- Left-brain introvert: “Welcome to the land of “Why should I? What’s in it for me?” This horse reads people like a book. He knows what you want and he’s not going to give it to you, unless you treat him right. Even though he appears stubborn or lazy, he’s not at all lazy in the mind! He may move slowly, but he’s always thinking quickly.”
- Right-brain introvert: “This shy, timid, shrinking violet avoids pressure by retreating into himself. Success involves going very slowly at first and waiting for him to come out of his shell, to trust more. Pretty soon he’ll be offering you more.”
- Right-brain extrovert: “This horse constantly needs reassurance. He gets confused easily and then gets afraid, so he needs you to make things simple, which will help him relax.”
A diagram is used to help decide which of these four characteristics predominates in aparticular horse.
Parelli™ Horsenality™ Profile.4 Using one chart per horse, the user places a mark within one of the three circles, in a cell adjacent to an adjective that seems to describe their horse. The inner (green) set of cells is used if your horse has the quality to a mild extent, the blue for moderate, and the yellow for extreme.
The Parellis offer many products to help you learn about Horsenality™ and “Humanility”, including a Digital Horsenality Report, a Digital Humanality Report, a Digital Humanality Match Report, a Digital Horsenality, Humanality & Match Report, a Horsenality Four-Disc DVD Set, a Printed Horsenality Report Deluxe Box Set, a Printed Horsenality, Humanality & Match Report Deluxe Box Set, and a Printed Humanality Report Deluxe Box Set. They practically give the stuff away at prices ranging from $79 to $269.5
The qualities in the chart above normally would be called “temperament” by psychologists. The Horsenality™ stuff seems to be drawn from the “four humors” (temperaments) in Greco-Roman medicine. This is a discredited proto-psychological theory that suggests that there are four fundamental temperaments:6
- Sanguine: boisterous, bubbly, chatty, openly emotional, optimistic, positive, active and social extroverts — much like the Horsenality™ LB Extrovert;
- Choleric: proud, short-tempered, fractious, or irritable extroverts — much like the Horsenality™ RB Extrovert;
- Melancholic: analytical, wise, quiet, emotionally sensitive, perfectionistic introverts. — much like the Horsenality™ LB Introvert;
- Phlegmatic: relaxed, peaceful, meek, who live to please others, submissive introverts — much like the Horsenality™ RB Introvert;
Considering the close match between the Four Temperaments and the horsenality™ stuff, I conclude that there is nothing new in horsenality™. There is nothing wrong with inventing something that was invented 2,500 years ago. But the four temperaments were discarded by psychologists and other scientists 100 years ago. And there may be something not quite right about earning a living by ignoring science and making stuff up.
The Parellis tell us that Horsenality™ is “horse personality”. But their conception of horsenality™ differs from the normal definition of personality in several ways:
- The Parellis tell us that horsenalities™ are innate.7 In humans, psychologists do not regard personality as innate. Personality is a product of socialization, is a social-cultural concept, is acquired and can be changed.
- The Parellis tell us that horses have multiple horsenalities™, although they have a dominant one8 and that horses often show horsenalities that are nearly opposite of their dominant one. Because personality describes dominant traits, humans aren’t expected to have multiple personalities. Such a thing might have been of interest to Freud, but it does not interest modern psychologists.
- The Parellis tell us that some horses switch horsenalities™ really fast depending on the situation they are in. In humans, personality traits are enduring personal characteristics that are revealed in a particular pattern of behavior in a variety of situations.9 Humans that bounce between personalities are diagnosed with dissociative identity disorder (multiple personality disorder, or “split personality”)
- The Parellis tell us that horses have only two dimensions for their horsenalities™. Psychologists often refer to five dimensions for personality: openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism (or emotional stability). It may be easy to imagine some of these same qualities in your horse.
I believe that the appeal of the horsenality™ literature is much like that of fortune cookies, horoscopes and the like: many people seem willing to believe what they are told if it seems to fit, without realizing that any good fortune cookie or horoscope mostly fits all people.
Fortune cookies are easy to believe: “Fame and fortune lie ahead”, “Love is right around the corner”, “Work with your destiny. Stop trying to outrun it.”, “Open your mind and your heart to good things.”, “Avoid negative people to stay positive.10”
Most horoscopes seem to apply to everyone, too. Consider these horoscopes:11
- “Expect to be frantic if you have to take care of something that’s time critical today. People and situations aren’t in your favor. Everything will seem like a challenge. Prioritize tasks and do them slowly and cautiously one at a time. If you push too hard, you will make mistakes and wear yourself out. The world won’t end if you don’t finish all your tasks.”
- “If you’ve given up on something you’ve lost, you might get a real surprise tonight when a dream sheds light on where you might find it. It’s important that you either get up and search for the object immediately or write the dream down in as much detail as you can remember. Otherwise, this could be one of those dreams that disappears as soon as you wake up, and you won’t want that.”
- “You could be introduced to a new person today. He or she may be someone who will play a very important role in your life at one point. You will feel an instant connection and find out you share a passion for the same kinds of things. This person could turn out to be a very good friend, and romance is also very likely. Take it slowly and see what happens.”
A trait is a quality that is stable across time and across situations. If we look for a trait, we aren’t looking for a horsenality™ where one day a horse can show a dominant quality, and another day its opposite. Nor do we want anything that a horse can quickly switch. We are looking for something as enduring as your horse’s height or weight, and that distinguishes him, to some degree, from the other horses in his herd. Traits name groups of correlated consistent behaviors.
So before launching into a discussion of how horses differ in personality, we need to spend a minute wondering what personality is.
- Personality is usually thought of as something that is stable across time — my personality today is similar to my personality when I was 12. Unfortunately.
- Personality is usually thought to be stable across situations. A person who is agreeable in three situations where others are disagreeable might be expected to be agreeable in a fourth situation.
- Personality, we think, should be describable with adjectives, referring to important, noticeable dimensions.
In the world of horses, many talk of a horse’s personality. In the world of science, animals don’t have personalities. They have temperaments or behavioral profiles. “Personality”, we learn, is to be considered a psycho-social construct comprising the content characteristics of human behavior (such as values, attitudes, habits, preferences, personal history, self-image). No one would deny that horses have habits, preferences, and personal history. I think both discussions should be extended: scientists should dare look at animal personality, and horse lovers should dare look at science.
There are two important questions we must answer if we are to talk intelligently about horse personality:
- What behaviors do horses show across situations and across time? For instance, if one horse is more aggressive than another in situation A, is he also likely to be more aggressive in situation B?
- How do we measure these behaviors?
Horse Personality as Rated by Humans
Users of the “horsenality™” test have no published scientific research to back up this instrument.12 There is no published research that shows that two raters of the same horse would give it the same rating, or that the ratings of a horse are stable over time. The Parellis themselves note that the score of a horse may change over time, and a horse can show behavior that is opposite that which is expected. If the authors of a test are uncomfortable using it to predict horse behavior, scientists would not be eager to try to validate it, and they would want to validate such a test before putting it into widespread use.
Where we do have science, we learn that human ratings of personality in the horse do not turn out well.
Consider this: in many European countries, horses are subjectively rated for character and temperament prior to being bred.13 But many problems face users of the test results. For instance, there are not clear definitions of the individual traits, nor universally accepted guidelines for evaluating them.14 As a result, those who provide these subjective ratings flounder, and most horses receive the same positive ratings.15
How do personality ratings by judges relate to behavioral measures of personality? One study16 which compared these two approaches found that “a few behaviour patterns significantly influenced several different personality traits in a very similar manner. Especially the latter finding suggests that judges do not clearly distinguish between the different personality traits but rather use their overall impression of a horse to then assign scores to the different, vaguely defined personality traits.”
Perhaps the rating approach works best when experts do the rating, and when they know the horses well. Or perhaps not: one study17 asked horse trainers who had been working with a small group of horses for seven months or more to rate 20 horses on 14 traits: Affectionate, Alert, Bold, Confident, Enthusiastic, Fizzy, Flighty, Honest, Intelligent, Laid, back, Lazy, Moody, Sensitive, and Sharp. Analysis showed that these trainers, who knew these horses well, did not agree with each other on any but two traits: sharp and flighty. The author of this study has convinced me. I agree with their conclusion that “It would appear that many current terms employed to describe personality in the horse are not reliably defined and should not be used, therefore, in any scientific context unless they are qualified by objective descriptive definitions.” And I would add: when only 2 of 14 tests are significant at the .05 level, there is not much to get excited about.
Perhaps there are differences between breeds that can emerge when humans use rating forms. In one study,18 human raters describe breeds using a 25-item Horse Personality Questionnaire.19 This questionnaire measures six underlying personality components: dominance, anxiousness, excitability, protection, sociability, and inquisitiveness. Some differences were found between breeds, particularly on dimensions of anxiousness and excitability. What we can’t know from such a study is whether the actual differences between breeds are the same as the perceived differences. Certainly we are all aware of the traditional views of various breeds. Such views may affect our judgment. I own a thoroughbred, and have heard a thousand times that thoroughbreds are flighty. I could easily believe this, because I have seen him nervous. But when we are attacked by a Doberman and he rears and flees, is this because he is a Thoroughbred or because he is a horse? And if a heron or deer leaps from the nearby vegetation, and he does not startle, is he perhaps not a Thoroughbred? We see the world that we expect to see.
Plaguing the rating approach to personality testing are a number of factors:
- Scores seem to be affected by the horse’s phenotype20 (the appearance of the horse).
- Judges make broad inferences from some behaviors. One study21 concludes with this: “a few behaviour patterns significantly influenced several different personality traits in a very similar manner. Especially the latter finding suggests that judges do not clearly distinguish between the different personality traits but rather use their overall impression of a horse to then assign scores to the different, vaguely defined personality traits.”
I believe it should be possible to develop a simple horse personality rating form that would be completed while a horse was observed in several different situations, such as grazing in the pasture, standing in a stall, free in the round pen, wandering an obstacle course in hand. Such situations should be chosen for their mundane realism — their similarity to the horse’s real world and normal day — so that reasonable extrapolations can be made from test results. I do not believe we should aspire to being able to infer more than a few traits from such observations — perhaps nervousness/confidence, inquisitiveness, and playfulness. We would need to determine the test-retest reliability of such an approach, to ensure that we were scoring trait, rather than state. We would want several observers, so that we could ensure inter-observer reliability. In the end, if we had built a sound assessment tool, we would still have to ask: what are we going to do with this thing?
This brief summary should be discouraging. Researchers use modern techniques and sophisticated statistical analysis, and no two studies were able to agree on what dimensions of personality might exist in an animal. Further, trainers who knew their horses well couldn’t even agree on the personalities of those horses. In fairness to the horse, our failures to identify personality are similar to the history of personality research in humans: jelly just doesn’t like to be nailed to a tree.
This doesn’t mean that personality in horses doesn’t exist. But it does mean that we aren’t finished figuring out how to measure it or talk about it. Maybe personality can be inferred from behavior.
Inferring Personality from Behavior
There is a small amount of research on personality (sometimes called “behavioral profiles”) in animals. Over time, these studies have grown more sophisticated, and have revealed more personality dimensions. Consider these:
- A 1964 study22 of infant rhesus monkeys used behavioral tests in a playroom situation, and found one dimension of personality: dominance — submission.
- A 1971 study23 of chimpanzees found four components of personality: affinitive, play, aggressive, and submissive.
- A 1972 study24 of juvenile rhesus monkeys in various social situations with infants, juveniles, and adults. The study found three main factors of personality: affiliative, hostile, and fearful. These factors were almost entirely independent and resembled the extraversion, psychoticism, and emotionality factors frequently found in humans.
- A 1994 study25 of gorillas found four main factors: extraverted, dominant, fearful, and understanding.
To some extent, such studies could be harmonized by playing with our language. Assuming that aggressiveness underlies the dominance-submission continuum, and that hostility is another word for aggressiveness, we find aggressiveness might have been assessed in all four studies above. Assuming that extraversion results in affinitive behaviors, then we find extraversion in studies 2-4 above.
The methods of assessing personality have improved, as have the statistical procedures available to analyze results. But the studies of monkeys and apes don’t yet agree on what dimensions of personality should be found. Nevertheless, the methods of these primate studies should be examined, and their results used for hypotheses about what we might find in the horse.
Personality judgments which are based on behavior need to be done carefully:
- A given behavior, such as head tossing, need not be a result of personality, but could be a sign of conflict due to incorrect negative reinforcement,26 resistance against the pain resulting from pressure of the bit,27 or the head posture induced by pressure on the bit.28 Pain can produce behaviors that should not be assumed to be reflections of personality.29 Environmental factors can affect behavior.30
- Whether the horse is being ridden or hand-walked, the human who accompanies him has a powerful effect on how he behaves and the personality he expresses. One study compared the temperament of when ridden, when led, and when released free. The authors conclude that “a rider or handler influences, but not completely masks, the horses’ intrinsic behaviour in a temperament test, and this influence appeared to be stronger on behavioural variables and heart rate variability than on the horses’ heart rates.31”
- Experience with handlers and riders past and present can affect a horse’s behavior. Such behavior induced by humans can likely be changed by other humans. I do not believe that these results should be considered to be “personality.32”
One recent study gives us hope that behavioral measures of certain personality dimensions may be feasible. Patricia Graf and her colleagues at the University of Göttingen33 devised a simple obstacle course to measure reactions to novel objects. Their goals were easy realization, low injury risk, and objective and reliable measurements. They chose five obstacles:
- two blue stationary balls lying on the ground;
- a red rolling ball rolling down from a ramp;
- A wooden bridge covered by a blue carpet lying on the ground;
- a narrow alleyway bordered by 2 rows each of 7 orange trafﬁc cones as well as 1.5-m high walls constructed from black wind-breaking net;
- a blue polystyrene bar lying on the ground
Horses were led or ridden through the obstacle course, and given one minute to deal with each obstacle. Riders were permitted to use various “aids” including spurs if a horse balked. Horses were scored for “reactivity” in a variety of ways on each obstacle.
Not surprisingly, horses were calmer with some obstacles, such as the stationary balls and the bar on the ground, than with others. These researchers found high correlations between the scores for reactivity and behavioral parameters including emotional expression, activity, time to calm down. Factors like breed-type, gender and age had significant influences on different scores of the temperament test. In most cases the rider or handler had no influence on the different scores assessed during the temperament test.
I think this study did it right: they measured an obvious and important quality (reactivity) under circumstances that our horses are often exposed to (the obstacle course). They used a large sample size (over 1,000 horses), a variety of testing facilities, a variety of breeds, and tested both with mounted riders and in hand. They used multiple measurements for reactivity, all of which seem to have face validity (appear to be an appropriate means of measuring reactivity). Their reward: lots of significant results. It has been three years, at this writing, since this study has been published, and it has only been cited five times. I hope it is recognized as an important study.
This study does leave us wondering how we might test for some of the other qualities mentioned in this chapter: Affectionate, Affiliative, Affinitive, Aggressive, Alert, Anxiousness, Bold, Confident, Dominance, Enthusiastic, Excitability, Extraversion, Fearfulness, Fizzy, Flighty, Honest, Hostile, Inquisitiveness, Intelligent, Laid back, Lazy, Moody, Play, Protection, Sensitive, Sharp, Sociability, Submission and Understanding. I can imagine that I find many of these qualities in my horse and/or my mule, but I don’t have good ideas on how to measure them.
Jodie Foreman34 offers these tips about working with horses of different personalities. I quote:
- “Clever / Curious. These are my favorite types. They like to always be learning something new. These horses are often good at choreography. Use props and toys. Let them add their own flair.
- Relaxed / Easy Going. Let them decide the pace.
- Nervous / Flighty. Work slowly. Use repetitions. Keep them below threshold.
- Bored / Switched off. Use props. Keep the sessions short.
- If the horse seems to like to pick things up, teach Fetch. Hat stealing. Touching. Play ball. Smile. Kiss.
- If the horse paws the ground, teach Spanish walk. Counting.
- For a horse that shakes his head, teach Yes and No. Head hug.
- For a horse that follows you around arena. Teach Heel (like a dog). Dance like me.
- Pay attention to what the horse doesn’t like. Don’t make a jock play chess.
- If a horse doesn’t like something, tricks can help the horse enjoy that thing.”
Her horse Bob initially did not like his face being touched. Now he nickers when she opens her hands for his cheeks.
1 Image source: Three weeks old Equus asinus in Kadzidłowo, Poland. https://en.wikipedia.org/wiki/Donkey#/media/File:Equus_asinus_Kadzid%C5%82owo_001.jpg
2 ExtrOversion v. ExtrAversion. The Parellis spell this word as extroversion, which is now the most common way this word is spelled. But psychologists are four times as likely to spell the word with an A as with an O, spelling it as Jung spelled it. Intro means “inside”. Extra means “outside”. Jung intended the word to refer to those who looked outward. See Kaufman, Scott Barry. “The Difference between ExtrAversion and ExtrOversion. What’s the correct spelling: ExtrAversion or ExtrOversion?” 2015. Scientific American. https://blogs.scientificamerican.com/beautiful-minds/the-difference-between-extraversion-and-extroversion/; Barnett, Greg. “Is it extraversion or extroversioin? We debunk the psychology behind this word and how you really should be spelling it.” Predictive Index. http://www.predictiveindex.com/blog/is-it-extraversion-or-extroversion; “Extrovert or extravert?” The Grammarphobia Blog January 11, 2016 http://www.grammarphobia.com/blog/2016/01/extrovert-extravert.html
3 Everything in this section on Horsenality that is in quotes is from Parelli, Linda “The Parelli Horsenality Profile” http://www.parelli.com/the-horsenality-profile.html
4 Image source: https://naturalnickyhorsemanship.files.wordpress.com/2015/10/horsenality-chart.jpg
6 My characterization of the four temperaments is drawn from both “The Four Temperaments” http://temperaments.fighunter.com/
7 “An owner’s manual for a horse? The Parelli Horsenality™ Report reveals your horse’s innate horse personality, or Horsenality, and gives you specific recommendations for success.” https://shop.parelli.com/catalog/education/horsenality—humanality-reports/
8 Natural Nicky Horsemanship. “Let’s Talk about the Horsenalities”. October 21, 2015. https://naturalnickyhorsemanship.com/2015/10/21/lets-talk-about-the-horsenalities/
9 “Personality” Wikipedia. https://en.wikipedia.org/wiki/Personality
10 Fortunes from http://Horoscope.com on Feb 1.2017.
11 Adapted slightly from three horoscopes at http://Horoscope.com on Feb 1.2017.
12 This is a bold claim, but a Google Scholar search on Feb 15, 2017 for “horsenality” revealed only 11 published articles, none of which touched on validating this test.
13 Koenen, E. P. C., L. I. Aldridge, and J. Philipsson. “An overview of breeding objectives for warmblood sport horses.” Livestock Production Science 88.1 (2004): 77-84.
14 Pasing, S., Christmann, L., Gauly, M., König von Borstel, U., 2011.Analysis of the status quo of personality evaluation in German horse breeding. In: Proceedings of the 62nd Annual Meeting of the European Association for Animal Production Stavanger, Norway, p. 142.
15 von Borstel, Uta König, Stephanie Pasing, and Matthias Gauly. “Towards a more objective assessment of equine personality using behavioural and physiological observations from performance test training.” Applied Animal Behaviour Science 135, no. 4 (2011): 277-285.
16 von Borstel, Uta König, Stephanie Pasing, and Matthias Gauly. “Towards a more objective assessment of equine personality using behavioural and physiological observations from performance test training.” Applied Animal Behaviour Science 135, no. 4 (2011): 277-285.
17 Mills, D. S. “Personality and individual differences in the horse, their significance, use and measurement.” Equine Veterinary Journal 30, no. S27 (1998): 10-13.
18 Lloyd, Adele Sian, Joanne Elizabeth Martin, Hannah Louise Imogen Bornett-Gauci, and Robert George Wilkinson. “Horse personality: variation between breeds.” Applied Animal Behaviour Science 112, no. 3 (2008): 369-383.
19 Lloyd, Adele Sian, Joanne Elizabeth Martin, Hannah Louise Imogen Bornett-Gauci, and Robert George Wilkinson. “Evaluation of a novel method of horse personality assessment: Rater-agreement and links to behaviour.” Applied Animal Behaviour Science 105, no. 1 (2007): 205-222.
20 König von Borstel, U., Pasing, S., Gauly, M., Christmann, L. Evaluation of
personality traits in horse breeding: analysis of the status quo in
Germany Appl. Anim. Behav. Sci., under review.; von Borstel, Uta König, Stephanie Pasing, and Matthias Gauly. “Towards a more objective assessment of equine personality using behavioural and physiological observations from performance test training.” Applied Animal Behaviour Science 135, no. 4 (2011): 277-285.
21 von Borstel, Uta König, Stephanie Pasing, and Matthias Gauly. “Towards a more objective assessment of equine personality using behavioural and physiological observations from performance test training.” Applied Animal Behaviour Science 135, no. 4 (2011): 277-285.
22 Locke, Katherine D., Edwin A. Locke, George A. Morgan, and Robert R. Zimmermann. “Dimensions of social interactions among infant rhesus monkeys.” Psychological Reports 15, no. 2 (1964): 339-349.
23 Van Hooff, J. A. R. A. M. “Facial expressions in higher primates.” In Symposium of the Zoological Society, London, vol. 8, pp. 97-125. 1962.
24 Chamove, A. S., H. J. Eysenck, and H. F. Harlow. “Personality in monkeys: Factor analyses of rhesus social behaviour.” The Quarterly Journal of Experimental Psychology 24, no. 4 (1972): 496-504.
25 Gold, Kenneth C., and Terry L. Maple. “Personality assessment in the gorilla and its utility as a management tool.” Zoo Biology 13, no. 5 (1994): 509-522.
26 deCartierd‘Yves,A., Ödberg, F.O., 2005.Apreliminary study onthe relation
between subjectively assessing dressage performance and objective
welfareparameters.In: Proceedings ofthe 1stInternational Equitation
Science Symposium, Melbourne, Australia, pp. 89–110.; McGreevy, P.D., McLean, A.N., Warren-Smith, A.K., Goodwin, D., 2005. Defining the terms and processes associated with equitation. In: Proceedings of the 1st International Equitation Science Symposium 2005, Melbourne, Australia, pp. 10–43.
27 Cook, W.R., 2003. Bit-induced pain: a cause of fear, flight, fight and facila neuralgia in the horse. Pferdeheilkunde 19, 75–82.; Ludewig, A.K., Gauly, M., König von Borstel, U., 2011. Effect of shortened reins on rein tension, stress and discomfort behaviour in dressage horses. Proceedings of the 7th International Equitation Science Conference, Hooge Mierde, The Netherlands, p. 61.
28 von Borstel, U.U., Duncan, I.J.H., Shoveller, A.K., Merkies, K., Keeling, L.J., Millman, S.T., 2009. Impact of riding in a coercively obtained Rollkur
posture on welfare and fear of performance horses. Appl. Anim. Behav.
Sci. 116, 228–236.
29 Cook, W.R., 1999. Pathophysiology of bit control in the horse. J. Equine Vet. Sci. 19, 196–204.; deCartierd‘Yves,A., Ödberg, F.O., 2005. A preliminary study on the relation between subjectively assessing dressage performance and objective welfare parameters. In: Proceedings of the 1st International Equitation Science Symposium, Melbourne, Australia, pp. 89–110.
30 Rivera, E., Benjamin, S., Nielsen, B., Shelle, J., Zanella, A.J., 2002. Behavioral and physiological responses of horses to initial training: the comparison between pastured versus stalled horses. Appl. Anim. Behav. Sci. 78, 235–252.; Søndergaard, E., Halekoh, U., 2003. Young horses’ reactions to humans in relation to handling and social environment. Appl. Anim. Behav. Sci. 84, 265–280.; Søndergaard, E., Ladewig, J., 2004. Group housing exerts a positive effect on the behaviour of young horses during training. Appl. Anim. Behav. Sci. 87, 105–118
31 Von Borstel, U. König, S. Euent, P. Graf, S. König, and M. Gauly. “Equine behaviour and heart rate in temperament tests with or without rider or handler.” Physiology & behavior 104, no. 3 (2011): 454-463.
32 Deuel, N.R., Lawrence, L.M., 1988. Effects of urging by the rider on gallop stride characteristics of quarter horses. J. Equine Vet. Sci. 8, 240–243.; Hausberger, M., Muller, C., 2002. A brief note on some possible factors involved in the reactions of horses to humans. Appl. Anim. Behav. Sci. 76, 339–344.; Hausberger, M., Bruderer, C., Scolan, N.L., Pierre, J.-S., 2004. Interplay between environmental and genetic factors in temperament/personality traits in horses (Equus caballus). J. Comp. Psychol. 118, 434–446.; Henry, S., Richard-Yris, M.A., Hausberger, M., 2006. Influence of various early human-foal interferences on subsequent human-foal relationship. Dev. Psychobiol. 48, 712–718.; König von Borstel, U., Euent, S., Graf, P., König, S., Gauly, M., 2011. Equine behaviour and heart rate in temperament tests with or without rider or handler. Physiol. Behav. 104, 454–463.
33 Graf, Patricia, Uta König von Borstel, and Matthias Gauly. “Practical considerations regarding the implementation of a temperament test into horse performance tests: results of a large-scale test run.” Journal of Veterinary Behavior: Clinical Applications and Research 9.6 (2014): 329-340.
34 Foreman, Jodie. Personal Communication, December, 2016.