Abstract: Abstract  When apes are not fully understood by humans, they persist with attempts to communicate, elaborating their behaviours to better convey their meaning. Such abilities have never been investigated in dogs. The present study aimed to clarify any effect of the visual attentional state of the owner on dogs’ (Canis familiaris) social-communicative signals for interacting with humans, and to determine whether dogs persist and elaborate their behaviour in the face of failure to communicate a request. Gaze at a hidden target or at the owner, gaze alternation between a hidden target and the owner, vocalisations and contacts in 12 guide and 12 pet dogs were analysed (i) when the dogs were asked by their owners (blind or sighted) to fetch their inaccessible toy and (ii) when the dogs were subsequently given an unfamiliar object (apparent unsuccessful communication) or their toy (apparent successful communication). No group differences were found, indicating no effect of the visual status of the owner on the dogs’ socio-communicative modes (i.e. no sensitivity to human visual attention). Results, however, suggest that the dogs exhibited persistence (but not elaboration) in their “showing” behaviours in each condition, except that in which the toy was returned. Thus, their communication was about a specific item in space (the toy). The results suggest that dogs possess partially intentional non-verbal deictic abilities: (i) to get their inaccessible toy, the dogs gazed at their owners as if to trigger their attention; gaze alternation between the owner and the target direction, and two behaviours directed at the target were performed, apparently to indicate the location of the hidden toy; (ii) after the delivery of the toy, the dogs behaved as if they returned to the play routine, gazing at their owner whilst holding their toy. In conclusion, this study shows that dogs possess partially intentional non-verbal deictic abilities: they exhibit successive visual orienting between a partner and objects, apparent attention-getting behaviours, no sensitivity to the visual status of humans for communication, and persistence in (but no elaboration of) communicative behaviours when apparent attempts to “manipulate” the human partner fail.

Abstract: Humans regularly produce new utterances that are understood by other members of the same language community. Linguistic theories account for this ability through the use of syntactic rules (or generative grammars) that describe the acceptable structure of utterances. The recursive, hierarchical embedding of language units (for example, words or phrases within shorter sentences) that is part of the ability to construct new utterances minimally requires a 'context-free' grammar that is more complex than the 'finite-state' grammars thought sufficient to specify the structure of all non-human communication signals. Recent hypotheses make the central claim that the capacity for syntactic recursion forms the computational core of a uniquely human language faculty. Here we show that European starlings (Sturnus vulgaris) accurately recognize acoustic patterns defined by a recursive, self-embedding, context-free grammar. They are also able to classify new patterns defined by the grammar and reliably exclude agrammatical patterns. Thus, the capacity to classify sequences from recursive, centre-embedded grammars is not uniquely human. This finding opens a new range of complex syntactic processing mechanisms to physiological investigation.

Abstract: Abstract: One advantage of living in a social group is the opportunity to use information provided by other individuals. Social information can be based on cues provided by a conspecific or even by a heterospecific individual (e.g., gaze direction, vocalizations, pointing gestures). Although the use of human gaze and gestures has been extensively studied in primates, and is increasingly studied in other mammals, there is no documentation of birds using these cues in a cooperative context. In this study, we tested the ability of three African gray parrots to use different human cues (pointing and/or gazing) in an object-choice task. We found that one subject spontaneously used the most salient pointing gesture (looking and steady pointing with hand at about 20 cm from the baited box). The two others were also able to use this cue after 15 trials. None of the parrots spontaneously used the steady gaze cues (combined head and eye orientation), but one learned to do so effectively after only 15 trials when the distance between the head and the baited box was about 1 m. However, none of the parrots were able to use the momentary pointing nor the distal pointing and gazing cues. These results are discussed in terms of sensitivity to joint attention as a prerequisite to understand pointing gestures as it is to the referential use of labels.

Abstract: The management of the domestic horse often requires them to be kept in isolation from con-specifics. Installing a picture of a horse (generally head and neck view) with a view to providing surrogate companionship has been shown to reduce the negative impact of this isolation. This study aimed firstly to compare the spontaneous response of horses (N=10) to a 2-D image of a horse’s face (FP) with their response to a comparable abstract 2-D image (AP). Secondly, the spontaneous response of horses (N=20) to a 2-D image of a horse’s face with the ears forward (PFP positive) was compared with the response to a 2-D image of a horse’s face with the ears back (NFP negative). The posters were A1 sized and displayed in the horse’s own stable. In study 1, one poster was displayed for 5 minutes and the horse’s behaviour video-recorded. This was removed and the second poster was displayed for 5 minutes and the behaviour video-recorded. FP was displayed first for 5 of the horses and AP displayed first for the other 5. The video footage was observed and the behaviour of the horses and number of times they touched the poster recorded. For the purpose of identifying the area of the poster that was touched by the horse it was divided into 4 equal quarters (TL, TR, BL, BR). In FP the nose of the horse in the 2-D image was located in BL, eyes and ears in TL, chest and lower neck in BR and upper neck in TR. In AP each area contained similar but unique abstract patterns of comparable colour to FP. Differences in behaviour were found according to which poster was displayed. FP was touched significantly more than AP (p=0.001) and was looked at more often (p=0.008). With FP the horses spent significantly longer with their ears forward (p=0.008) and licking and chewing (p=0.016). When the number of touches per poster area was compared (FP and AP) a significant difference was found in the number of times that BL (nose) and BR (chest/lower neck) were touched (p=0.011). Both areas were touched more frequently on FP, with BL being touched the most. In study 2 the same experimental protocol was used to compare responses to positive (PFP) or negative (NFP) 2-D images of a horse’s face (same horse in both PFP and NFP). Again, differences in behaviour were found in response to the two posters. PFP was touched significantly more than NFP (p=0.002) and on both posters the area BL (nose) was touched more frequently than the other areas (PFP: p=0.02, NFP: p=0.01). More ears back behaviour (p<0.001) and more ear locked on behaviour (p=0.008) was shown with NFP. The results of these studies indicate that horses can recognize 2-D images as con-specifics as well as responding to differences in facial expression. There is now the potential for further investigation into the importance of other visual cues in recognition and social interaction as well as the application of findings to enhance equine welfare.