Abstract: Abstract  Discrimination learning studies suggest that horses learn more easily using spatial than visible object-specific (OS) cues. However, spatial cues have generally confounded intra-array, distal and/or egocentric spatial information. It is also unclear whether conflicting cues compete for association or are redundantly encoded, and furthermore, the influence of prior experiences or training has not been quantified so far. We examined the effect of cue modality on unweaned foals’ performance in a discrimination learning task. After a pilot study confirmed that horses could perform the required OS cue discrimination, nine foals learnt to find food in one of three covered buckets, in any of four positions within a test arena. In Stage 1 the rewarded bucket was signified both by OS cues (pattern) and by relative spatial cues (position). On reaching criterion, cues were separated and foals had to ignore the inappropriate cue (Stage 2). Foals assigned to follow spatial cues (n = 5) completed Stage 2 faster than foals for whom OS cues remained consistent (n = 4). Spatial group foals all reached criterion without delay; no foal in the OS group reached criterion within the testing period. OS group foals initially persisted in responding to the previously correct position, adopting spatially-based strategies when this proved unsuccessful. The findings show for the first time that, even in the absence of distal spatial information, intra-array spatial cues were more salient than OS cues for foals in a food-finding task and learning appeared rather inflexible.

Abstract: Abstract  Many animal species that rely mainly on calls to communicate produce individual acoustic structures, but we wondered whether individuals of species better known as visual communicants, with small vocal repertoires, would also exhibit individual distinctiveness in calls. Moreover, theoretical advances concerning the evolution of social intelligence are usually based on primate species data, but relatively little is known about the social cognitive capacities of non-primate mammals. However, some non-primate species demonstrate auditory recognition of social categories and possess mental representation of their social network. Horses (Equus caballus) form stable social networks and although they display a large range of visual signals, they also use long-distance whinny calls to maintain contact. Here, we investigated the potential existence of individual acoustic signatures in whinny calls and the ability of horses to discriminate by ear individuals varying in their degree of familiarity. Our analysis of the acoustic structure of whinnies of 30 adult domestic horses (ten stallions, ten geldings, ten mares) revealed that some of the frequency and temporal parameters carried reliable information about the caller’s sex, body size and identity. However, no correlations with age were found. Playback experiments evaluated the behavioural significance of this variability. Twelve horses heard either control white noise or whinnies emitted by group members, familiar neighbours or unfamiliar horses. While control sounds did not induce any particular response, horses discriminated the social category of the callers and reacted with a sound-specific behaviour (vigilance and attraction varied with familiarity). Our results support the existence of social knowledge in horses and suggest a process of vocal coding/decoding of information.

Abstract: Abstract  Recent research has shown that domestic dogs are particularly good at determining the focus of human attention, often outperforming chimpanzees and hand-reared wolves. It has been suggested that the close evolutionary relationship between humans and dogs has led to the development of this ability; however, very few other domestic species have been studied. We tested the ability of 36 domestic horses to discriminate between an attentive and inattentive person in determining whom to approach for food. The cues provided were body orientation, head orientation or whether the experimenters’ eyes were open or closed. A fourth, mixed condition was included where the attentive person stood with their body facing away from the subjects but their head turned towards the subject while the inattentive person stood with their body facing the subject but their head turned away. Horses chose the attentive person significantly more often using the body cue, head cue, and eye cue but not the mixed cue. This result suggests that domestic horses are highly sensitive to human attentional cues, including gaze. The possible role of evolutionary and environmental factors in the development of this ability is discussed.

Abstract: Abstract  The human–horse relationship has a long evolutionary history. Horses continue to play a pivotal role in the lives of humans and it is common for humans to think their horses recognize them by face. If a horse can distinguish his/her human companion from other humans, then evolution has supplied the horse with a very adaptive cognitive ability. The current study used operant conditioning trials to examine whether horses could discriminate photographed human faces and transfer this facial recognition ability a novel setting. The results indicated the horses (a) learned to discriminate photographs of the unrelated individuals, fraternal twins, and identical twins and (b) demonstrated transfer of facial recognition by spending more time with their S+ woman in the field test.

Abstract: Abstract  The study raises the question of whether guide dogs and pet dogs are expected to differ in response to cues of referential communication given by their owners; especially since guide dogs grow up among sighted humans, and while living with their blind owners, they still have interactions with several sighted people. Guide dogs and pet dogs were required to respond to point, point and gaze, gaze and control cues of referential communication given by their owners. Results indicate that the two groups of dogs do not differ from each other, revealing that the visual status of the owner is not a factor in the use of cues of referential communication. Both groups of dogs have higher frequencies of performance and faster latencies for the point and the point and gaze cues as compared to gaze cue only. However, responses to control cues are below chance performance for the guide dogs, whereas the pet dogs perform at chance. The below chance performance of the guide dogs may be explained by a tendency among them to go and stand by the owner. The study indicates that both groups of dogs respond similarly in normal daily dyadic interaction with their owners and the lower comprehension of the human gaze may be a less salient cue among dogs in comparison to the pointing gesture.