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Author Christensen, J.W.
Title Object habituation in horses: Voluntary vs. negatively reinforced approach to frightening stimuli Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue Pages
Keywords Habituation; learning; fearfulness; stress; reinforcement
Abstract The ability and ease of horses to habituate to frightening stimuli greatly increases safety in the horse-human relationship. Several different techniques have been suggested for habituation training of horses and under certain conditions, preventing animals from avoidance reactions during exposure to frightening stimuli is believed to facilitate habituation. Response prevention does, however, lead to a loss of control, which is a known stress inducer in both animals and humans. This experiment investigated whether horses show increased stress responses when negatively reinforced to approach a mildly frightening stimulus, compared to horses allowed to voluntarily explore the same stimulus. We further investigated whether the prevention of avoidance responses in horses that are negatively reinforced to approach the stimulus, facilitates habituation to the stimulus. Twenty-two 2-3 years old Danish warmblood geldings were included in the study. Half of the horses (NR group) were negatively reinforced (through halter and rope pressure) by a familiar human handler to approach a collection of frightening objects (six open and colourful umbrellas) placed in a semi-circle in a familiar test arena. The other half of the horses were released in the arena and were free to avoid or explore the objects (VOL group). On the next day, all horses were exposed to the objects again without a human to investigate the rate of habituation. Behavioural and heart rate responses were recorded on both days. Data were analysed in a two way repeated measures ANOVA and post hoc analysed via the Holm-Sidak method. In the VOL group, all horses initially chose to avoid the unknown objects, whereas the handler managed to get all horses in the NR group to approach and stand next to the objects within the first 2-min session. As expected, horses in the NR group had a significantly longer duration of alertness (sec, mean ± se: NR: 23 ± 4.1 vs. VOL: 16 ± 4.7, P=0.026) and a higher max HR in the first session (bpm, mean ± se: NR: 106 ± 5.2 vs. VOL: 88 ± 4.4, P=0.004). On the next day, however, the NR horses spent significantly less time investigating the objects (sec, mean ± se: NR: 13 ± 4.1 vs. VOL: 24 ± 6.0, P=0.005) and had a shorter latency to approach a feed container, placed next to the objects (sec, mean ± se: NR: 25 ± 3.9 vs. VOL: 47 ± 16.2, P=0.031), indicating increased habituation. In conclusion, negatively reinforced approach to mildly frightening objects appears to increase stress responses during the initial exposure, but also to facilitate habituation in young horses.
Address
Corporate Author Christensen, J.W. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5499
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Author Rørvang, M.V.; Christensen, J.W.; Ladewig, J.; McLean, A.
Title Social Learning in Horses--Fact or Fiction? Type Journal Article
Year 2018 Publication Frontiers in Veterinary Science Abbreviated Journal Front. Vet. Sci.
Volume 5 Issue Pages 212
Keywords
Abstract Prima facie, the acquisition of novel behaviors in animals through observation of conspecifics seems straightforward. There are, however, various mechanisms through which the behavior of animals can be altered from observing others. These mechanisms range from simple hard-wired contagious processes to genuine learning by observation, which differ fundamentally in cognitive complexity. They range from social facilitation and local enhancement to true social learning. The different learning mechanisms are the subject of this review, largely because research on learning by observation can be confounded by difficulties in interpretation owing to the looming possibility of associative learning infecting experimental results. While it is often assumed that horses are capable of acquiring new behavior through intra-species observation, research on social learning in horses includes a variety of studies some of which may overestimate the possession of higher mental abilities. Assuming such abilities in their absence can have welfare implications, e.g. isolating stereotypical horses on the assumption that these behaviors can be learned though observation by neighboring horses. This review summarizes the definitions and criteria for the various types of social transmission and social learning and reviews the current documentation for each type in horses with the aim of clarifying whether horses possess the ability to learn through true social learning. As social ungulates, horses evolved in open landscapes, exposed to predators and grazing most of the day. Being in close proximity to conspecifics may theoretically offer an opportunity to learn socially, however anti-predator vigilance and locating forage may not require the neural complexity of social learning. Given the significant energetic expense of brain tissue, it is likely that social facilitation and local enhancement may have been sufficient in the adaptation of equids to their niche. As a consequence, social learning abilities may be maladaptive in horses. Collectively, the review proposes a novel differentiation between social transmission (social facilitation, local and stimulus enhancement) and social learning (goal emulation, imitation). Horses are undoubtedly sensitive to intra-species transfer of information but this transfer does not appear to satisfy the criteria for social learning, and thus there is no solid evidence for true social learning in horses.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 2297-1769 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 6558
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Author Rørvang, M.V.; Ahrendt, L.P.; Christensen, J.W.
Title Horses fail to use social learning when solving spatial detour tasks Type Journal Article
Year 2015 Publication Animal Cognition Abbreviated Journal Anim.Cogn.
Volume 18 Issue 4 Pages 847-854
Keywords
Abstract Social animals should have plenty of opportunities to learn from conspecifics, but most studies have failed to document social learning in horses. This study investigates whether young Icelandic horses can learn a spatial detour task through observation of a trained demonstrator horse of either the same age (Experiments 1 and 2, n = 22) or older (Experiment 3, n = 24). Observer horses were allowed to observe the demonstrator being led three times through the detour route immediately before being given the opportunity to solve the task themselves. Controls were allowed only to observe the demonstrator horse eating at the final position, but not the demonstration of the route. Although we found a tendency towards better performance by observer horses in the second experiment, we were unable to repeat this result in a similar set-up with a new group of horses and older, dominant demonstrator horses. We conclude that horses exposed to prior demonstration did not perform better than control horses in solving spatial detour tasks.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 1435-9456 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Rørvang2015 Serial 6130
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Author Hartmann, E.; Christensen, J.W.; McGreevy, P.D.
Title Dominance and leadership: Useful concepts in human-horse interactions? Type Journal Article
Year Publication Journal of Equine Veterinary Science Abbreviated Journal Journal of Equine Veterinary Science
Volume Issue Pages
Keywords
Abstract Dominance hierarchies in horses primarily influence priority access to limited resources of any kind, resulting in predictable contest outcomes that potentially minimize aggressive encounters and associated risk of injury. Levels of aggression in group-kept horses under domestic conditions have been reported to be higher than in their feral counterparts but can often be attributed to sub-optimal management. Horse owners often express concerns about the risk of injuries occurring in group-kept horses but these concerns have not been substantiated by empirical investigations. What has not yet been sufficiently addressed are human safety aspects related to approaching and handling group-kept horses. Given horses? natural tendency to synchronize activity to promote group cohesion, questions remain about how group dynamics influence human-horse interactions. Group dynamics influence a variety of management scenarios, ranging from taking a horse out of its social group to the prospect of humans mimicking the horse?s social system by taking a putative leadership role and seeking after an alpha position in the dominance hierarchy to achieve compliance. Yet, there is considerable debate about whether the roles horses attain in their social group are of any relevance in their reactions to humans. This article reviews the empirical data on social dynamics in horses, focusing on dominance and leadership theories and the merits of incorporating those concepts into the human-horse context. This will provide a constructive framework for informed debate and valuable guidance for owners managing group-kept horses and for optimizing human-horse interactions.
Address
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0737-0806 ISBN Medium
Area Expedition Conference
Notes doi: 10.1016/j.jevs.2017.01.015 Approved no
Call Number Equine Behaviour @ team @ Serial 6048
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Author Hartmann, E.; Christensen, J.W.; McGreevy, P.D.
Title Dominance and Leadership: Useful Concepts in Human-Horse Interactions? Type Journal Article
Year 2017 Publication Journal of Equine Veterinary Science Abbreviated Journal Proceedings of the 2017 Equine Science Symposium
Volume 52 Issue Pages 1-9
Keywords Horse; Social order; Dominance hierarchy; Aggression; Injury; Learning; Training
Abstract Dominance hierarchies in horses primarily influence priority access to limited resources of any kind, resulting in predictable contest outcomes that potentially minimize aggressive encounters and associated risk of injury. Levels of aggression in group-kept horses under domestic conditions have been reported to be higher than in their feral counterparts but can often be attributed to suboptimal management. Horse owners often express concerns about the risk of injuries occurring in group-kept horses, but these concerns have not been substantiated by empirical investigations. What has not yet been sufficiently addressed are human safety aspects related to approaching and handling group-kept horses. Given horse's natural tendency to synchronize activity to promote group cohesion, questions remain about how group dynamics influence human-horse interactions. Group dynamics influence a variety of management scenarios, ranging from taking a horse out of its social group to the prospect of humans mimicking the horse's social system by taking a putative leadership role and seeking after an alpha position in the dominance hierarchy to achieve compliance. Yet, there is considerable debate about whether the roles horses attain in their social group are of any relevance in their reactions to humans. This article reviews the empirical data on social dynamics in horses, focusing on dominance and leadership theories and the merits of incorporating those concepts into the human-horse context. This will provide a constructive framework for informed debate and valuable guidance for owners managing group-kept horses and for optimizing human-horse interactions.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0737-0806 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 6712
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Author Christensen, J.W.; Rundgren, M.; Olsson, K.
Title Training methods for horses: habituation to a frightening stimulus Type Journal Article
Year 2006 Publication Equine veterinary journal Abbreviated Journal Equine Vet J
Volume 38 Issue 5 Pages 439-443
Keywords Animals; Behavior, Animal/*physiology; *Conditioning (Psychology); *Fear; Heart Rate/*physiology; Horses/physiology/*psychology; Learning; Male; Random Allocation; *Reinforcement (Psychology); Safety; Time Factors
Abstract REASONS FOR PERFORMING STUDY: Responses of horses in frightening situations are important for both equine and human safety. Considerable scientific interest has been shown in development of reactivity tests, but little effort has been dedicated to the development of appropriate training methods for reducing fearfulness. OBJECTIVES: To investigate which of 3 different training methods (habituation, desensitisation and counter-conditioning) was most effective in teaching horses to react calmly in a potentially frightening situation. HYPOTHESES: 1) Horses are able to generalise about the test stimulus such that, once familiar with the test stimulus in one situation, it appears less frightening and elicits a reduced response even when the stimulus intensity is increased or the stimulus is presented differently; and 2) alternative methods such as desensitisation and counter-conditioning would be more efficient than a classic habituation approach. METHODS: Twenty-seven naive 2-year-old Danish Warmblood stallions were trained according to 3 different methods, based on classical learning theory: 1) horses (n = 9) were exposed to the full stimulus (a moving, white nylon bag, 1.2 x 0.75 m) in 5 daily training sessions until they met a predefined habituation criterion (habituation); 2) horses (n = 9) were introduced gradually to the stimulus and habituated to each step before the full stimulus was applied (desensitisation); 3) horses (n = 9) were trained to associate the stimulus with a positive reward before being exposed to the full stimulus (counter-conditioning). Each horse received 5 training sessions of 3 min per day. Heart rate and behavioural responses were recorded. RESULTS: Horses trained with the desensitisation method showed fewer flight responses in total and needed fewer training sessions to learn to react calmly to test stimuli. Variations in heart rate persisted even when behavioural responses had ceased. In addition, all horses on the desensitisation method eventually habituated to the test stimulus whereas some horses on the other methods did not. CONCLUSIONS AND POTENTIAL RELEVANCE: Desensitisation appeared to be the most effective training method for horses in frightening situations. Further research is needed in order to investigate the role of positive reinforcement, such as offering food, in the training of horses.
Address Danish Institute of Agricultural Sciences, Department of Animal Health, Welfare and Nutrition, Tjele, Denmark
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0425-1644 ISBN Medium
Area Expedition Conference
Notes PMID:16986605 Approved no
Call Number Serial 1783
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Author Christensen, J.W.; Malmkvist, J.; Nielsen, B.L.; Keeling, L.J.
Title Effects of a calm companion on fear reactions in naive test horses Type Journal Article
Year 2008 Publication Equine Veterinary Journal Abbreviated Journal Equine Vet J
Volume 40 Issue 1 Pages 46-50
Keywords
Abstract REASON FOR PERFORMING STUDY: In fear-eliciting situations, horses tend to show flight reactions that can be dangerous for both horse and man. Finding appropriate methods for reducing fearfulness in horses has important practical implications. OBJECTIVES: To investigate whether the presence of a calm companion horse influences fear reactions in naive subject horses. HYPOTHESES: The presence of a habituated (calm) companion horse in a fear-eliciting situation can reduce fear reactions in naive subject horses, compared to subject horses with a nonhabituated companion (control). METHODS: Minimally handled (n = 36), 2-year-old stallions were used, 18 as subjects and 18 as companions. Companion horses (n = 9) were habituated to an otherwise frightening, standardised test stimulus (calm companions), whereas the rest (n = 9) of the companion horses remained nonhabituated (control companions). During the test, unique pairs of companion and subject horses were exposed to the test stimulus while heart rate and behavioural responses were registered. Subsequently, subject horses were exposed to the stimulus on their own (post test). RESULTS: Subject horses, paired with a calm companion horse, showed less fear-related behaviour and lower heart rate responses compared to subject horses with control companions. Results from the post test suggest that the difference between treatment groups remained in the subsequent absence of companion horses. CONCLUSIONS AND POTENTIAL RELEVANCE: It appears possible to reduce fear reactions in young, naive horses by allowing them to interact with a calm companion horse in fear-eliciting situations.
Address Department of Animal Health, Welfare and Nutrition, Faculty of Agricultural Sciences, University of Aarhus, PO Box 50, DK-8830 Tjele, Denmark
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0425-1644 ISBN Medium
Area Expedition Conference
Notes PMID:18083659 Approved no
Call Number Equine Behaviour @ team @ Serial 4355
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Author Christensen, J.W.; Zharkikh, T.; Ladewig, J.
Title Do horses generalise between objects during habituation? Type Journal Article
Year 2008 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 114 Issue 3-4 Pages 509-520
Keywords Horse; Stimulus generalisation; Habituation; Fear
Abstract Habituation to frightening stimuli plays an important role in horse training. To investigate the extent to which horses generalise between different visual objects, 2-year-old stallions were habituated to feeding from a container placed inside a test arena and assigned as TEST (n=12) or REFERENCE horses (n=12). In Experiment 1, TEST horses were habituated to six objects (ball, barrel, board, box, cone, cylinder) presented in sequence in a balanced order. The objects were of similar size but different colour. Each object was placed 0.5m in front of the feed container, forcing the horses to pass the object to get to the food. TEST horses received as many 2min exposures to each object as required to meet a habituation criterion. We recorded behavioural reactions to the object, latency to feed, total eating time, and heart rate (HR) during all exposures. There was no significant decrease in initial responses towards a novel object with increasing object number, indicating that habituation was stimulus-specific. REFERENCE horses were exposed to the test arena without objects in the same period, and reactions of TEST and REFERENCE horses were subsequently compared in a fear-test (2m2.5m rubber mat placed under the feed container, forcing the horses to step on the mat to get food). There were no significant differences between the treatment groups, i.e. previous habituation of TEST horses to six visual objects did not reduce responses in a fear-test involving visual and tactile stimulation. Due to the lack of generalisation in Experiment 1, we designed a supplemental experiment (Experiment 2), in which REFERENCE horses were exposed to the same six objects except that object colour was kept constant. We found a significant reduction in response (behaviour and HR) with increasing object number, indicating that horses generalise between similarly coloured objects of varying shape. We conclude that a high degree of object similarity, e.g. identical colouring, appears to be crucial for object generalisation in horses.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0168-1591 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 4756
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Author Hartmann, E.; Christensen, J.W.; Keeling, L.J.
Title Social interactions of unfamiliar horses during paired encounters: Effect of pre-exposure on aggression level and so risk of injury Type Journal Article
Year 2009 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 121 Issue 3-4 Pages 214-221
Keywords Equine; Behaviour; Welfare; Mixing; Housing; Wounds
Abstract Group housing of horses is not widely applied in practice despite the welfare advantages of keeping animals socially rather than individually. In particular, concerns have been raised about the possible increased risk of injury and how to introduce a new horse into an established group. This study investigated two hypotheses: (1) pre-exposure of young horses in neighbouring boxes reduces the frequency of aggressive interactions when the same horses are subsequently put together in a paddock compared to horses without this previous box experience, (2) the occurrence of aggressive behaviour, in particular contact aggression in the paddock can be predicted after observing the horses' social interactions in neighbouring boxes. Danish Warmblood mares (n = 20), 2 years old, were kept in two groups of 10 horses. In total, 60 encounters were arranged whereby each horse was confronted pair-wise with six horses from the other group, three according to each treatment: treatment I--box (B) and subsequent paddock meeting (BP), and treatment II--only paddock meeting (P). Horses met in neighbouring boxes for 5 min and together in the same paddock for 10 min. The frequencies of aggressive and non-aggressive interactions were analysed from video recordings. Total aggression levels between BP and P did not differ, but [`]contact aggression', i.e. bite, kick, strike, push, tended to be lower in BP compared to P (median BP = 1, P = 2; p = 0.083) and there were less bites in BP than P (median BP = 0, P = 1; p = 0.050). Frequencies of [`]non-aggressive' interactions, e.g. friendly approach, nasal sniff, were lower in BP than P (median BP = 2.5, P = 10; p < 0.01). Results further revealed that [`]bite threat' performed in boxes correlated with [`]contact aggression' in the paddock (r = 0.46, p = 0.011). In conclusion, pre-exposure of young horses in neighbouring boxes may reduce [`]contact aggression', especially biting, in the paddock and [`]bite threat' shown in boxes may help to predict contact aggression when horses are later turned out together. The reduced non-aggressive interactions in the paddock in the BP test were probably a consequence of horses having exchanged these behaviours in the preceding B test. Exposing young horses in boxes next to each other may be a helpful tool before mixing them because horses meet in a safe environment that could assist in reducing the type of aggression where horses are most at risk of being injured.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0168-1591 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5089
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Author Christensen, J.W.; Zharkikh, T.; Chovaux, E.
Title Object recognition and generalisation during habituation in horses Type Journal Article
Year 2011 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 129 Issue 2-4 Pages 83-91
Keywords Horse; Habituation; Object recognition; Generalisation
Abstract The ability of horses to habituate to frightening stimuli greatly increases safety in the horse-human relationship. A recent experiment suggested, however, that habituation to frightening visual stimuli is relatively stimulus-specific in horses and that shape and colour are important factors for object generalisation (Christensen et al., 2008). In a series of experiments, we aimed to further explore the ability of horses (n = 30, 1 and 2-year-old mares) to recognise and generalise between objects during habituation. TEST horses (n = 15) were habituated to a complex object, composed of five simple objects of varying shape and colour, whereas CONTROL horses (n = 15) were habituated to the test arena, but not to the complex object. In the first experiment, we investigated whether TEST horses subsequently reacted less to i) simple objects that were previously part of the complex object (i.e. testing for object recognition) and ii) a novel object (new shape and colour, i.e. testing for object generalisation), compared to CONTROLS. In the second experiment we investigated whether TEST horses reacted to a change in object order and object location. Behavioural reactions to the object, latency to eat, total eating time and heart rate were recorded. Compared to CONTROLS, TEST horses reacted significantly less towards objects, which were previously part of the complex object (e.g. mean heart rate; P = 0.006), indicating object recognition. In contrast to our expectations, TEST horses also reacted significantly less towards the novel object (e.g. mean heart rate; P = 0.018), suggesting that they were capable of object generalisation. We also found that TEST horses showed an increase in exploratory behaviour when objects within the complex object changed order and location (both P < 0.001), whereas there was no increase in heart rate, indicating that the horses were not frightened by the changes. The results demonstrate that it is possible to increase object generalisation in horses by habituating them to a range of colours and shapes simultaneously. This knowledge greatly affects the way in which horses may be trained to react calmly towards frightening objects.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0168-1591 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5328
Permanent link to this record