Abstract: This field study tested the hypothesis that domestic horses living under putatively challenging-to-welfare conditions (for example involving social, spatial, feeding constraints) would present signs of poor welfare and co-occurring pessimistic judgement biases. Our subjects were 34 horses who had been housed for over 3 years in either restricted riding school situations (e.g. kept in single boxes, with limited roughage, ridden by inexperienced riders; N = 25) or under more naturalistic conditions (e.g. access to free-range, kept in stable social groups, leisure riding; N = 9). The horses' welfare was assessed by recording health-related, behavioural and postural indicators. Additionally, after learning a location task to discriminate a bucket containing either edible food ('positive' location) or unpalatable food ('negative' location), the horses were presented with a bucket located near the positive position, near the negative position and halfway between the positive and negative positions to assess their judgement biases. The riding school horses displayed the highest levels of behavioural and health-related problems and a pessimistic judgment bias, whereas the horses living under more naturalistic conditions displayed indications of good welfare and an optimistic bias. Moreover, pessimistic bias data strongly correlated with poor welfare data. This suggests that a lowered mood impacts a non-human species' perception of its environment and highlights cognitive biases as an appropriate tool to assess the impact of chronic living conditions on horse welfare.

Abstract: Keas, a species of parrots from New Zealand, are an interesting species for comparative studies of problem solving and cognition because they are known not only for efficient capacities for object manipulation but also for explorative and playful behaviors. To what extent are they efficient or explorative, and what cognitive abilities do they use? We examined how keas would solve several versions of artificial-fruit box problems having multiple locks. After training keas to remove a metal rod from over a Plexiglas lid that had to be opened, we exposed the birds to a variety of tasks having two or more locks. We also introduced a preview phase during which the keas had extended opportunity to look at the tasks before the experimenter allowed the birds to solve them, to examine whether the preview phase would facilitate the birds' performance on the tasks. In a large number of tests, the keas showed a strong trend to solve the tasks with no positive effect of previewing the tasks. When the tasks became complex, however, the keas corrected inappropriate responses more quickly when they had had chance to preview the problems than when they had not. The results suggest that the keas primarily used explorative strategies in solving the lock problems but might have obtained some information about the tasks before starting to solve them. This may reflect a good compromise of keas' trial-and-error tendency and their good cognitive ability that result from a selection pressure they have faced in their natural habitat.

Abstract: In Experiment 1, rats choosing in an E maze preferred to release a rat standing in a pool of water to dry ground over a rat already standing on dry ground. Five additional experiments showed that the choosing rat's preference for releasing the wet rat was maintained by two separable outcomes: (1) the social contact offered by the released rat and (2) the reinforcing value of proximity to a pool of water. These results call into question Sato et al.'s (Anim Cogn 18:1039-1047, 2015) claim to have demonstrated that a rat's releasing of a wet rat to dry ground is empathically motivated.

Abstract: A previous study demonstrated that horses can learn socially from observing humans, but could not draw any conclusions about the social learning mechanisms. Here we develop this by showing horses four different human action sequences as demonstrations of how to press a button to open a feed box. We tested 68 horses aged between 3 and 12 years. 63 horses passed the habituation phase and were assigned either to the group Hand Demo (N = 13) for which a kneeling person used a hand to press the button, Head Demo (N = 13) for which a kneeling person used the head, Mixed Demo (N = 12) for which a squatting person used both head and hand, Foot Demo (N = 12) in which a standing person used a foot, or No Demo (N = 13) in which horses did not receive a demonstration. 44 horses reached the learning criterion of opening the feeder twenty times consecutively, 40 of these were 75% of the Demo group horses and four horses were 31% of the No Demo group horses. Horses not reaching the learning criterion approached the human experimenters more often than those who did. Significantly more horses used their head to press the button no matter which demonstration they received. However, in the Foot Demo group four horses consistently preferred to use a hoof and two switched between hoof and head use. After the Mixed Demo the horses' actions were more diverse. The results indicate that only a few horses copy behaviours when learning socially from humans. A few may learn through observational conditioning, as some appeared to adapt to demonstrated actions in the course of reaching the learning criterion. Most horses learn socially through enhancement, using humans to learn where, and which aspect of a mechanism has to be manipulated, and by applying individual trial and error learning to reach their goal.

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.