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Baragli, P., & Regolin, L. (2008). Cognitive Tests in Equids (Equus caballus and Equus Asinus). In IESM 2008.
Abstract: For ages horses and donkeys constituted the most important domesticated animals. Even though equids were often bred and kept in close proximity to humans, surprisingly little is known about their cognitive abilities. Traditionally, horses are not regarded as clever animals; common beliefs maintain that the horses“ behaviour is merely driven by conditioned-responses. Additionally, from an anthropomorphic point of view donkeys are believed to be ”stupid" animals.
Our study investigates the equids“ ability to recover a hidden object. For this purpose the animal has to create and maintain a representation of the object and its location in space, from the moment in which it disappears from direct perception, till the moment in which it reappears. The knowledge about objects being entities that continue to exist even when they are no longer available for direct perception is refered to as the well known concept of ”object permanence".
We primarly assessed the ability of Esperia's pony and donkeys to solve a Detour problem while employing an opaque “U-shaped” barrier. Each animal observed a food bucket moving and disappearing behind the barrier. Immediately after the object"s disappearance, the animal was released to search for the object. If it solved the task by detouring the barrier it was positively reinforced.
The ability to retain in memory the hidden object as well as its spatial location was subsequently tested in the presence of two, rather than one, screens (Working Memory testing phase). The food bucket was made to move and hidden behind one of the two identical screens, while the animal was watching it. Following a pre-established delayed period of 10 sec, the animal was set free to look for the food. In such a test the detour problem is combined with the classical delayed-response task, which is in use for the comparison of memory duration in different species.
In order to recover the hidden objects, animals must encode, maintain and correctly regain from their working memory the existence of the no longer visible object and its location from their working memory.
Both donkeys and ponies performed the Detour task showing to grasp the fact that an object which is no longer perceivable still continues to exist and can be regained. They also were able to correctly retrieve the goal object after a delay of 10 s in the Working Memory tasks, showing that they had encoded, maintained and correclty retrieved from their working memory the spatial location of the hidden object as well as its existence.
Nevertheless, when Standardbreds, raised in traditional stables, were tested in identical conditions to those describe for the ponies and donkeys, they could not succeed in the Detour tasks. The reason for such differences needs to be studied Even though it would be interesting to focus on handling differences, i.e., the ponies had been living in an environment rich in natural stimuli, while the Standardbreds had lived in a man-controlled environment since birth. It is also noteworthy that, like donkeys, the Esperia's pony have a reputation for being hard to handle.
Several considerations could arise from our preliminary investigations, and we will have the pleasure to leave them open for discussion.
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Lovrovich, P., Sighieri, C., & Baragli, P. (2012). The human-given cues and behavioural plasticity of horses during a delayed three choice task. In K. Krueger (Ed.), Proceedings of the 2. International Equine Science Meeting (Vol. in press). Wald: Xenophon Publishing.
Abstract: Recent studies have tested the ability of horses to understand human gestures. But even at the moment results are rather contradictory. This study was aimed at analyzing ability of horses to understand, remember and use human-given cues in a delayed three choice task. After the training period, sixteen horses had to choose between three blue buckets. One of them hid a carrot. Eight horses (A-group) saw the person hiding the carrot and they had to choose the correct bucket only after the person had hidden carrot and gone away. Control group, eight horses (B-group) did not know where the carrot was, and could only choose the bucket through the use of smell or by random choice. Each horse carried out 10 trials in the same test session. A-group chose the correct bucket to a greater extent on the first try (4.37±1.42), compared to the second (3.00±0.53) and the third try (0.75±0.71). With significant differences between the first and the second try (t14=2.582, p=0.022), the first and the third try (t14=6.508, p=0.000), and between the second and the third try (t14=7.180, p=0.000). Also the B-group chose the correct bucket to a greater extent on the first try (3.87±0.83) compared to the second (3.37±1.51) and the third (1.75±1.49). Anyway, there was no differences between the first and the second try (t14=0.821, p=0.425). As regards the B-group, statistical differences were found between the first and the third try (t14=3.523, p=0.003) and between the second and the third try (t14=2.171, p=0.048). Moreover, A-group showed a negative correlation (r=-0.652, p=0.0409) between the number of correct answers at first trial, and seemed that they used human information during the first half of the trials. As the trials proceeded, the average time required to find carrot decreased, with a negative correlation (r=-0.779, p=0.0079) over trials while, the number of overturned bucket to find carrot increased over trials (r=0.770, p=0.0091). As the trials proceeded, the horses tended to choose at first the bucket where the carrot had been found in the previous trial (r=0.450, p=0.013). Any kind of correlation over trials was found in B-group. In the first trials, the horses we studied seemed to understand human given-cues information, store it and use it appropriately even in absence of a person. As trials proceeded they seemed to change strategy, searching carrots where it had been found in the previous trial. Therefore, horses could use human given-cues or other cognitive strategy depending on the time, energy cost and mental effort required to solve the task. KW -
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Baragli, P., Demuru, E., & Palagi, E. (2015). Mirror on the wall, who is the horsest of our all? Self-recognition in Equus caballus. In Proceedings of the 3. International Equine Science Meeting.
Abstract: Mirror Self-Recognition (MSR) is an extremely rare capacity in the animal kingdom that reveals the emergence of complex cognitive capacities (de Waal 2008). So far, MSR has been reported only in humans, chimpanzees (Gallup, 1970), bottlenose dolphins (Reiss and Marino, 2001) and Asian elephants (Plotnik et al, 2006), all species characterized by a highly developed cognition. There is growing evidence that domestic horses posses high cognitive abilities, such as cross-modal individual recognition (Proops et al, 2009), triadic post-conflict reunion to maintain social homeostasis (Cozzi et al, 2010), complex communicative systems (Whatan and McComb, 2014), flexibility in problem-solving (Lovrovich et al, 2015), and long-term memory (Hanggi and Ingersoll, 2009). All these capacities make horses a good candidate to test the ability of MSR in a domestic species. Through a classical MSR experimental paradigm (de Waal 2008) we tested eight horses living in social groups under semi-natural conditions (from the Italian Horse Protection rescue centre). Animals showing MSR typically go through four stages (Plotnik et al, 2006): (i) social response, (ii) physical mirror inspection (e.g., looking behind the mirror), (iii) repetitive mirror-testing behaviour (i.e., the beginning of mirror understanding), and (iv) self-directed behaviour (i.e., recognition of the mirror image as self). The final stage, known as the “mark-test”, is verified when a subject spontaneously uses the mirror to check for a coloured artificial mark on its own body which it cannot perceive otherwise. The horses underwent a three-phase “mark-test”: 1) with sham mark (transparent ultrasound water gel) positioned on both side at jaw level, 2) mark (yellow eye shadow mixed with ultrasound water gel) positioned on left side of jaw (with sham mark on the right), 3) mark (yellow eye shadow mixed with ultrasound water gel) positioned on right side of jaw (with sham mark on the left)
The mirror was one 0.5-cm-thick piece of 140x220-cm plexiglass glue on wood. Each test lasted one hour, horses were tested once a day, in consecutive days and at the same time. Our preliminary result on 1 horse shows some changes in self-directed behaviours which can be attributed to presence of the coloured mark. Firstly, the presence of the coloured mark significantly increased the frequency of scratching on both sides of the muzzle (p < 0.0001). The most intriguing result (p < 0.0001) comes from the comparison of the scratching rates directed towards the coloured mark side (N = 41) and the sham mark side (N = 23). Under the control condition (i.e. sham mark on both sides) no statistical difference was found for the scratching rates directed to the muzzle sides (dx N = 8; sx N = 5). Although further analyses are needed to confirm these preliminary results, our finding opens new scenarios about the evolution of Mirror Self-Recognition. The capacity of horses to recognize themselves in a mirror may be the outcome of an evolutionary convergence process driven by the cognitive pressures imposed by a complex social system and maintained despite thousands years of domestication.
Keywords:
Domestic horse · Mark test · Socio-cognitive skills · Self-awareness
References
De Waal FBM (2008) The thief in the mirror. PloS Biol 6(8):e201
Gallup GG Jr (1970) Chimpanzees: Self-recognition. Science 167: 86-87.
Reiss D, Marino L (2001). Mirror self-recognition in the bottlenose dolphin: A case of cognitive convergence. Proc Natl Acad Sci U S A 98:5937-5942.
Plotnik J, de Waal FBM, Reiss D (2006) Self-recognition in an Asian elephant. Proc Natl Acad Sci U S A 103: 17053-17057.
Proops L, McComb K, Reby D. (2009) Cross-modal individual recognition in domestic horses (Equus caballus). Proc Nat Acad Sci USA;106:947-951.
Cozzi A, Sighieri C, Gazzano A, Nicol CJ, Baragli P. Post-conflict friendly reunion in a permanent group of horses (Equus caballus). Behav Process 2010;85:185-190.
Wathan J, McComb K. The eyes and ears are visual indicators of attention in domestic horses. Curr Biol 2014;24(15): R677-R679.
Lovrovich P, Sighieri C, Baragli P (2015) Following human-given cues or not? Horses (Equus caballus) get smarter and change strategy in a delayed three choice task. Appl Anim Behav Sci, in press.
Hanggi EB, Ingersoll JF. (2009) Long-term memory for categories and concepts in horses (Equus caballus). Anim Cogn; 12:451-462.
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Lanata, A., Guidi, A., Valenza, G., Baragli, P., & Scilingo, E. P. (2017). The Role of Nonlinear Coupling in Human-Horse Interaction: a Preliminary Study. In 2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC).
Abstract: This study focuses on the analysis of humanhorse
dynamic interaction using cardiovascular information
exclusively. Specifically, the Information Theoretic Learning
(ITL) approach has been applied to a Human-Horse Interaction
paradigm, therefore accounting for the nonlinear information
of the heart-heart interplay between humans and horses.
Heartbeat dynamics was gathered from humans and horses
during three experimental conditions: absence of interaction,
visual-olfactory interaction, and brooming. Cross Information
Potential, Cross Correntropy, and Correntropy Coefficient were
computed to quantitatively estimate nonlinear coupling in a
group of eleven subjects and one horse. Results showed a
statistical significant difference on all of the three interaction
phases. Furthermore, a Support Vector Machine classifier
recognized the three conditions with an accuracy of 90:9%.
These preliminary and encouraging results suggest that ITL
analysis provides viable metrics for the quantitative evaluation
of human-horse interaction.
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Baragli, P., Vitale, V., Paoletti, E., Mengoli, M., & Sighieri, C. (2011). Encoding the Object Position for Assessment of Short Term Spatial Memory in Horses (Equus caballus). International Journal of Comparative Psychology, 24(3).
Abstract: In this study, the detour problem was combined with the classic delayed-response task to investigate equine short-term spatial memory. Test subjects were eight female horses, divided into two groups (A and B) of four subjects each. The motivating object was made to move and disappear behind one oftwo identical obstacles in a two-point-choice apparatus. After a 10 s (Group A) or 30 s (Group B) delay the animal was released to seek the object. Both groups made more correct (14.8 ± 1.3 forGroup A and 13.5 ± 3.1 for Group B, mean ± SD) than incorrect choices (5.3 ± 1.3 for Group A and6.5 ± 3.1 for Group B, mean ± SD) and the performance of each group was significantly above chance level (z = 4.14, p = 0.000, for Group A and z = 3.02, p = 0.002, for Group B). Therefore, tested animals were able to recover the object by approaching the correct obstacle after 10 s or 30 s delays, showing that they had encoded and recovered from memory the existence of the target object and its location.
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Baragli, P., Scopa, C., Maglieri, V., & Palagi, E. (2021). If horses had toes: demonstrating mirror self recognition at group level in Equus caballus. Anim. Cogn., .
Abstract: Mirror self-recognition (MSR), investigated in primates and recently in non-primate species, is considered a measure of self-awareness. Nowadays, the only reliable test for investigating MSR potential skills consists in the untrained response to a visual body mark detected using a reflective surface. Here, we report the first evidence of MSR at group level in horses, by facing the weaknesses of methodology present in a previous pilot study. Fourteen horses were used in a 4-phases mirror test (covered mirror, open mirror, invisible mark, visible colored mark). After engaging in a series of contingency behaviors (looking behind the mirror, peek-a-boo, head and tongue movements), our horses used the mirror surface to guide their movements towards their colored cheeks, thus showing that they can recognize themselves in a mirror. The analysis at the group level, which 'marks' a turning point in the analytical technique of MSR exploration in non-primate species, showed that horses spent a longer time in scratching their faces when marked with the visible mark compared to the non-visible mark. This finding indicates that horses did not see the non-visible mark and that they did not touch their own face guided by the tactile sensation, suggesting the presence of MSR in horses. Although a heated debate on the binary versus gradualist model in the MSR interpretation exists, recent empirical pieces of evidence, including ours, indicate that MSR is not an all-or-nothing phenomenon that appeared once in phylogeny and that a convergent evolution mechanism can be at the basis of its presence in phylogenetically distant taxa.
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Baragli, P., Tedeschi, D., Masini, A. P., Magnaghi, N., Martelli, F., & Sighieri, C. (2001). Estimation of performance in elite endurance horses by means of an exercise test in field conditions. Valutazione della performance in cavalli da endurance di elite mediante test diesercizio in campo, 12(1), 13–19.
Abstract: In human sports medicine exercise tests are normally used to check training progression. Correlation tests between blood lactate concentration and exercise speed are often used for this purpose. Studies have been done to adjust exercise tests for athletic horses using the same principle. The aim of this work was to verify the practical possibility that the anaerobic threshold in elite endurance horses could be calculated by adjusting a submaximal exercise field test in order to obtain reference parameters for endurance horses. Ten selected horses from the Italian National Endurance Team were used for this study. The tests were conducted on an 800 meters grass oval. Horses performed three steps (800 meters every step), at increasing speed with two minute intervals between each step. Riders were informed of the ideal speed for every step (5, 7.5, 10 m/s) and the real velocity was calculated on the basis of time taken to finish a single step. Blood samples were obtained via venipuncture from the jugular vein, immediately before the beginning of the test and 60 seconds after the end of each step. The following parameters were evaluated for each horse: individual anaerobic threshold (VSI), anaerobic threshold (V4) and exercise velocity corresponding to a lactate concentration of 2 mM/I (V2). Analysis of results indicate that lactate concentration is exponentially related to exercise speed for the entire test. VSI, V4, V2, were (mearttsd): 25.7±5.1; 30.5±2.5; 21.1±2.9 km/h respectively.
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Guidi, A., Lanata, A., Valenza, G., Scilingo, E. P., & Baragli, P. (2017). Validation of smart textile electrodes for electrocardiogram monitoring in free-moving horses. J. Vet. Behav., 17, 19–23.
Abstract: This article focuses on the validation of smart textile electrodes used to acquire electrocardiogram (ECG) signals in horses in a comfortable and robust manner. The performance of smart textile electrodes is compared with standard Ag/AgCl electrodes in terms of the percentage of motion artifacts (MAs, the noise that results from the movement of electrodes against the skin) and signal quality. Seven healthy Standardbred mares were equipped with 2 identical electronic systems for the simultaneous collection of ECGs. One system was equipped with smart textile electrodes, whereas the second was equipped with standard Ag/AgCl electrodes. Each horse was then monitored individually in a stall for 1 hour, without any movement constraints. The ECGs were visually examined by an expert who blindly labeled the ECG segments that had been corrupted by MAs. Finally, the percentage of MAs (MA%) was computed as the number of samples of the corrupted segments over the whole length of the signal. The total MA% was found to be lower for the smart textiles than for the Ag/AgCl electrodes. Consistent results were also obtained by investigating MAs over time. These results suggest that smart textile electrodes are more reliable when recording artifact-free ECGs in horses at rest. Thus, improving the acquisition of important physiological information related to the activity of the autonomic nervous system, such as heart rate variability, could help to provide reliable information on the mood and state of arousal of horses.
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Baragli, P., Mariti, C., Petri, L., De Giorgio, F., & Sighieri, C. (2011). Does attention make the difference? Horses' response to human stimulus after 2 different training strategies. J Vet Behav Clin Appl Res, 6(1), 31–38.
Abstract: We hypothesized that in an open environment, horses cope with a series of challenges in
their interactions with human beings. If the horse is not physically constrained and is free to move
in a small enclosure, it has additional options regarding its behavioral response to the trainer. The
aim of our study was to evaluate the influence of 2 different training strategies on the horse’s behavioral
response to human stimuli. In all, 12 female ponies were randomly divided into the following 2
groups: group A, wherein horses were trained in a small enclosure (where indicators of the level of
attention and behavioral response were used to modulate the training pace and the horse’s control over
its response to the stimuli provided by the trainer) and group B, wherein horses were trained in a closed
environment (in which the trainer’s actions left no room for any behavioral response except for the one
that was requested). Horses’ behavior toward the human subject and their heart rate during 2 standardized
behavioral tests were used to compare the responses of the 2 groups. Results indicated that the
horses in group A appeared to associate human actions with a positive experience, as highlighted by
the greater degree of explorative behavior toward human beings shown by these horses during the tests.
The experience of the horses during training may have resulted in different evaluations of the person, as
a consequence of the human’s actions during training; therefore, it seems that horses evaluate human
beings on daily relationship experiences.
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Gatta, D., Baragli, P., Ferrarini, N., Ciattini, F., Sighieri, C., & Colombani, B. (1998). Fitness evaluation in endurance horses by standardised exercise test on treadmill. Valutazione dello stato di allenamento del cavallo da endurance mediante test standardizzato su trea, 9(4), 57–69.
Abstract: Endurance horses, like marathon runners, undertake sub-maximal, longterm physical exercises and in both cases thermoregulation plays a critical role. A standardised sub-maximal treadmill test was used to assess fitness and training state in endurance horses. Literature reports that trained human athletes dissipate head load better than not trained ones; in this study parameters related to thermoregulation were recorded together with other haematologic and metabolic ones. Six endurance horses, divided into two groups according to their training state, performed two submaximal tests at a distance of one week. Blood samples were collected at rest, during exercise, at the end and during recovery (10, 30 and 60 minutes after work). Heart rate (HR), respiratory rate (RR), rectal (RT) and skin (ST) temperatures were monitored through the exercise (and recovery for HR). HR resulted significantly lower (P<0.01) in trained horses than in untrained ones, especially during recovery. Also rectal and skin temperatures resulted significantly lower (P<0.05) in trained horses and ST increased more gradually during exercise. The values of haematocrit and haemoglobin resulted significantly lower (P<0.05) at rest, during exercise and recovery samples. In this study, the parameters related to thermoregulation, in accordance with data from human athletes, resulted significantly different in trained and untrained horses, while other parameters didn't vary significantly between the two groups. Thermoregulatory responses to exercise-generated heat load in a standardised test, studied by simple parameters, can thus offer useful information about fitness and training state of endurance horses.
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