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Domjan, M. (1976). Determinants of the enhancement of flavored-water intake by prior exposure. J Exp Psychol Anim Behav Process, 2(1), 17–27.
Abstract: The intake of a 2.0% sodium saccharin solution in rats was observed to increase as a function of both the number (Experiment 1) and the duration (Experiment 3) of prior periods of access to the saccharin flavor, but did not increase when subjects were maintained on a fluid deprivation procedure in the absence of saccharin exposure (Experiment 2). The enhancement of intake was further influenced by the schedule of saccharin preexposures in the absence of variations in the amount of solution tasted (Experiment 4). The effect was not a function of the opportunity for subjects to determine their own pattern of contact with the saccharin flavor, the opportunity for association of the flavor with hunger and thirst reduction, or the amount of saccharin swallowed during preexposure (Experiment 5). These results suggest that mere exposure to a flavored solution is sufficient to increase subsequent intakes. The phenomenon is discussed in terms of the attenuation of neophobia elicited by the novelty of flavored solutions.
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Nelson, E. E., Shelton, S. E., & Kalin, N. H. (2003). Individual differences in the responses of naive rhesus monkeys to snakes. Emotion, 3(1), 3–11.
Abstract: The authors demonstrated individual differences in inhibited behavior and withdrawal responses of laboratory-born rhesus monkeys when initially exposed to a snake. Most monkeys displayed a small significant increase in their behavioral inhibition in the presence of a snake. A few monkeys had marked responses, and some actively withdrew. Although the responses of the most extreme laboratory-born monkeys were comparable to feral-born monkeys, the responses of the laboratory-born monkeys rapidly habituated. The individual differences in the responses of naive monkeys likely reflect a continuum from orienting to wariness to fear. A neurobiological model is presented that addresses potential mechanisms underlying these individual differences, their relation to fear, and how they may predispose to phobia development.
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Breuer, K., Hemsworth, P. H., & Coleman, G. J. (2003). The effect of positive or negative handling on the behavioural and physiological responses of nonlactating heifers. Appl. Anim. Behav. Sci., 84(1), 3–22.
Abstract: This experiment investigated the effects of positive and negative tactile handling on the stress physiology and behaviour of dairy heifers. Forty-eight 5-14-month-old nonlactating Holstein-Friesian heifers were allocated to one of two handling treatments, either positive or negative tactile handling, over four time replicates. Handling was imposed twice daily, 2-5 min per session and involved moving animals individually along a 64 m outdoor route. The negatively handled heifers took longer to approach within 1 and 2 m of a stimulus person in a standard test, than their positively handled counterparts (P<0.001) and had a greater flight distance to an approaching stimulus (P<0.001). The time taken by the heifers to approach within 1 and 2 m of a familiar person was similar to that taken to approach within 1 and 2 m of an unfamiliar person in the standard test (P<0.05). There was a tendency for heifers to have a greater flight distance from the approaching unfamiliar person than from the approaching familiar person (P=0.06). The negatively handled heifers had greater (P<0.05) increases in total cortisol concentrations 5, 10 and 15 min after exposure to a human and had higher (P<0.05) free cortisol concentrations in the afternoon than the positively handled heifers. It is concluded that the nature of the human contact affects the subsequent behavioural response of heifers to humans. This behavioural response may extend to other humans through the process of stimulus generalisation, although there was some evidence of moderate discrimination. Negative handling results in an acute stress response in the presence of humans and also leads to a chronic stress response. Further research into the effect of these stress responses on milk production and welfare in fearful cows in a commercial situation is suggested.
Keywords: Dairy heifer; Fear; Handling; Stress response; Milk production; Stimulus generalisation
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Hedman, J. (2003). Heart rate response towards fear-eliciting stimuli in horses (Vol. 2004). Bachelor's thesis, , Dept. of Animal Environment and Health, SLU. Examensarbete / Sveriges lantbruksuniversitet, Veterinä.
Abstract: Finding the right horse for each rider is a difficult task as it is just as important that the temperament of the horse fits the rider as it is that the horse is of the right size. Even though it is a commonly experienced problem, no objective method of easily measuring the horse“s temperament has yet been developed. If it is possible to test horses and get an objective measure of how reactive (emotional) they are, it could be a big help in finding the right horse for each rider. It would be desirable to have a way of testing the horse”s reaction in an unfamiliar (and potentially frightening) situation. In practice this test should be just as easy as it is getting a judgement of its conformation and gaits.
The aim of the present study was to measure individual variation in HR response to different novel objects in horses of the same age, breed and reared in the same environment. We wanted to see whether certain horses (i.e. more emotional horses) react more to novel stimuli, in general, than other horses (i.e. less emotional), irrespective of the type of stimulus. We also wanted to see if different novel stimuli elicited different responses within individuals. The hypothesis was that individuals will react in a similar way to various stimuli. Twenty four Danish warmblood horses were included in this study. All horses were 2 year-old stallions, reared under similar environmental conditions. They had received a minimum of handling prior to the experimental period. Three different stimuli were used. They were chosen because they were novel to the horses and would elicit measurable fear-reactions in all horses, but not so much that the horses did not approach the feed within the duration of the test. The visual stimulus consisted of a 1meter high orange traffic cone with reflex stripes, placed 1 m in front of the tub, the olfactory stimulus was eucalyptus oil and the auditory stimulus was a radio tuned to white noise. The control was an empty arena. The result was that only the HR response to the auditory and visual stimuli differed significantly from the control days. The olfactory stimulus did not seem to alarm the horses the way the other stimuli did. We found a tendency towards a correlation in reaction between the olfactory and auditory stimuli and between the auditory and visual stimuli within individuals. These results indicate that horses do not generalize completely in their reaction between different stimuli. Keywords: horse, fear, heart-rate, novel stimuli
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Christensen, J. W. (2012). Object habituation in horses: Voluntary vs. negatively reinforced approach to frightening stimuli. In K. Krueger (Ed.), Proceedings of the 2. International Equine Science Meeting (Vol. in press). Wald: Xenophon Publishing.
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.
Keywords: Habituation; learning; fearfulness; stress; reinforcement
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Vidament, M., Yvon. J.-M., Roche, H., Le Bon, H., Menard, C., Delfosse, A., et al. (2012). Temperament of stallions: relation with age, breed and level of riders. In K. Krueger (Ed.), Proceedings of the 2. International Equine Science Meeting (Vol. in press). Wald: Xenophon Publishing.
Abstract: Temperament is an important factor when working with horses. Behavioral tests have been developed to measure certain dimensions in horses. Relations between temperament and ability to riding activity have been highlighted (Lansade 2008a). The aims of this study were 1) to evaluate the effect of age on temperament, 2) to verify that temperament are related to breeds 3) to check if the ease to be ridden is in relation with temperament, on a first set of data. Five dimensions of temperament have been measured in 98 field stallions (Table 1). They were tested as described by Lansade (2008 a,b): fearfulness/curiosity (tests: crossing a novel aera, suddenly opening an umbrella, novel object), gregariousness (test: isolation), locomotor activity (during the other tests), reactivity/curiosity to a non familiar human (tests: passive and active human), tactile (Von Frey filament) and auditory sensitivities. Table 1: Number of stallions according to breed (or group of breeds) and age. Breeds or groups of breeds Young (<13 years) Old (>=13 <20 years) Merens 1 15 10 Leasure horse breeds 2 13 10 Jumping pony breeds 3 / 20 Jumping horse breeds4 9 10 Arabians / 11 Total 37 61 (1) Merens : french mountain horse breed (2) Appaloosa, Barbe, Lusitanian, Polish, Paint (3) French Saddle Pony, Connemara, New Forest, Welsh (4) French Saddle Horse, Anglo-Arab, KWPN, Foreign breeds Effect of age. Due to imbalanced data, only stallions from 3 breed groups were compared (29 young ones selected at random and 30 old ones). Young stallions presented a higher emotivity (more elevated distance/intensity of the flight after umbrella opening (P=0.001)) and curiosity (more sniffings/nibblings the passive human (P=0.04) and the novel object (P<0.0001)) compared to old ones. Relation with breed groups. In young stallions, differences were noted : in the number of trots during social isolation (P=0.001) and in the tactile sensitivity (P=0.005). Merens had smaller values than Jumping horses for these 2 variables. In older stallions, differences were also noted: in the number of sniffings/nibblings the novel object (P=0.04), in the manner to cross the novel aera (P=0.03), in the distance and intensity of the flight after umbrella opening (P=0.04), in the number of trots during isolation (P=0.02) and in the tactile sensitivity (P=0.03). Merens had lower reactivity compared: 1) to Arabians (for novel aera) and 2) compared to Jumping ponies and Jumping horses (for isolation and tactile sensitivity). Minimal level of rider. Stallions of all ages and breeds were divided into 3 groups according to the level of riders able to ride them safely, according to a questionnaire: beginners, intermediate level and pre-national competition level. Stallions adapted to beginners showed lower values in the number of trots during isolation (P=0.02) and in the tactile sensitivity (P=0.03) than stallions rode by pre-competition level riders. Conclusion : The intensity of fear reactions to suddenness decreased with age. Differences between breeds and eases of use have been related to temperament measurements.
Keywords: temperament, age, breed, fear, gregarity
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Rocha, A. D. de L., Menescal-de-Oliveira, L., & da Silva, L. F. S. (2017). Effects of human contact and intra-specific social learning on tonic immobility in guinea pigs, Cavia porcellus. Appl. Anim. Behav. Sci., .
Abstract: Abstract Social learning is the capacity of animals to acquire adaptive information from others. In the case of fear responses, animals can learn fearful or non-fearful responses by observing the behavior of conspecifics. Tonic immobility (TI) is an anti-predatory behavior elicited during intense fear situations. Studies have revealed that regular contact with humans can reduce TI responses in animals. In our study, we evaluated the effect of human contact on the TI responses in guinea pigs. We also evaluated the effect of cohabitation (non-fearful animals with fearful animals) on their TI responses. To achieve this, we measured the TI responses induced by postural inversion and restraint in guinea pigs as a result of different treatments. In our first experiment, we determined the effect of human contact on TI responses by establishing 3 treatment groups: no contact, handled, and habituated. In our second experiment, we addressed the effect of social learning on TI response by testing TI response in habituated, and unhabituated animals that had cohabitated for 10 days. In the first experiment, 10 days of either handling or habituation did not prevent TI in guinea pigs, but habituation did increase latency [F(2,119) = 14.19; p < 0.0001] and handling or habituation decrease duration [F(2,119) = 15.01; p < 0.0001] of the TI behavior in the guinea pigs. In the second experiment, the cohabitation of unhabituated and habituated animals reduced TI duration [F(2,93) = 5.058; p < 0.008]. These data suggest that both forms of human interaction can reduce experimenter fear in guinea pigs. It therefore seems that unhabituated guinea pigs learn not to fear the experimenter by cohabitating with habituated guinea pigs.
Keywords: Cohabitation; Fear; Motor response; Defensive behaviour; Predator-prey
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