Do dogs spontaneously recognise their owner’s face in photographs?

Previous research has shown that in order for a dog to recognise its owner, the owner’s head and face needs to be visible. Furthermore, it has been found that dogs can learn to discriminate familiar and unfamiliar 2D representations of human faces. However, it currently remains unclear whether dogs spontaneously recognise their owner’s face in photographs. Therefore, the aim of the current experiment was to determine if dogs could distinguish between a photo of their owner’s face from a photo of a stranger’s face. The current paradigm separated dogs from their owners which tested the dog’s ability to recognise their owner’s face in a photograph to achieve reunion. During the test procedure, dogs (N = 23) were positioned in front of a large screen with multiple covered windows, that the owner and stranger both stood behind. When dogs were looking centrally, two lower curtains were opened revealing the owner’s and stranger’s legs. Following this, two windows above (head height) were opened revealing life-sized photos of the owner’s and stranger’s face with neutral expressions, then the dogs were released. The photographs were taken in either optimal conditions (looking straight forward, taken with flash) or sub-optimal conditions (looking left or right, up or down, artificial light, taken without flash). There was also an odour condition in which only the people’s legs were revealed. Results revealed that dogs (N = 15) went to their owner significantly more than the stranger in the sub-optimal condition (P = .039). Dogs also went to their owner more often in the optimal condition (N = 13), although this difference was not significant (P = .192). Finally, dogs chose their owner at chance level (50%) during the odour condition (P = .500), clearly demonstrating that dogs did not use scent in the task to facilitate their performance. In summary, dogs are able to recognise their owner’s face from photographs, but the optimal conditions for face recognition seem to differ from those of humans

Do dogs (Canis familiaris) recognize a familiar species in cross-modal presentation?

A recent study has shown that dogs can recognize conspecifics in cross-modal presentations. The aim of the present study was to assess if dogs are also able to recognize other species and if different levels of exposure to them can influence this capability. The designated species was the cat, as it is relatively easy to find dogs with specific degrees of exposure. To this aim, we enrolled 60 pet dogs, half of which had at least one cat in their household, while the other half had never been living with cats. Using a cross-modal audio-video violation of expectancy paradigm, dogs were presented with either a cat or a dog vocalization followed by a cat or a dog video, thus facing either a congruent or an incongruent pair of stimuli. As expected, dog paid more attention, an indication of surprise, after being presented with the incongruent stimulus of dog vocalization followed by cat video (meanse=10.91.0) compared to the coherent dog stimuli (10.40.9; p=0.015 GLMM), supporting that they recognized the conspecific’s stimuli. However, this was not the case for the cat-related stimuli: the congruent cat stimuli (13.80.9) attracted more attention than the incongruent pair (13.40.9; p=0.011). This was likely due to the fact that the cat vocalization did not generate in dogs an expectation that could have been violated, and suggesting that dogs did not recognize the stimuli belonging to cats. In fact, the two cat stimuli might have elicited higher attention for being novel, again supporting the inability of dogs to recognize cats in this type of presentations. There was no effect of cohabitation with cats on attention paid by dogs (p=0.556). This indicates that living with another species in adult life does not seem sufficient to promote recognition with this methodology. This may be due to the exposure to a limited number/variety of cats or to the lack of exposure during the socialization phase

Dogs (Canis lupus familiaris) are susceptible to the Kanizsa’s triangle illusion

none5siThe ability to complete partially missing contours is widespread across the animal kingdom, but whether this extends to dogs is still unknown. To address this gap in knowledge, we assessed dogs’ susceptibility to one of the most common contour illusions, the Kanizsa’s triangle. Six dogs were trained to discriminate a triangle from other geometrical figures using a two21 alternative conditioned discrimination task. Once the learning criterion was reached, dogs were presented with the Kanizsa’s triangle and a control stimulus, where inducers were rotated around their centre, so as to disrupt what would be perceived as a triangle by a human observer. As a group, dogs chose the illusory triangle significantly more often than control stimuli. At the individual level, susceptibility to the illusion was shown by five out of six dogs. This is the first study where dogs as a group show susceptibility to a visual illusion in the same manner as humans. Moreover, the analyses revealed a negative effect of age on susceptibility, an effect that was also found in humans. Altogether, this suggests that the underling perceptual mechanisms are similar between dogs and humans, and in sharp contrast with other categories of visual illusions to which the susceptibility of dogs has been previously assessed.partially_openMiina Lõoke, Lieta Marinelli, Cécile Guérineau, Christian Agrillo, Paolo MongilloLõoke, Miina; Marinelli, Lieta; Guérineau, CÉCILE, CHANTAL, CATHERINE; Agrillo, Christian; Mongillo, Paol

Yes, dogs are susceptible to!the!Kanizsa’s triangle illusion: A!reply to Pepperberg (Learn. Behav. 51:5–6, 2023)

A recent paper by Pepperberg, Learning & Behavior, 51, 5–6, (2023) enquires about the validity of the finding that dogs are susceptible to the Kanizsa’s triangle illusion, reported by Lõoke and coauthors (Lõoke et al., Animal Cognition, 25, 43–51, 2022). Here we elaborate on the matter, providing both theoretical considerations and further data, supporting the soundness of our previous conclusions

Determining Hearing Thresholds in Dogs Using the Staircase Method

There is a growing interest in performing playback experiments to understand which acoustical cues trigger specific behavioral/emotional responses in dogs. However, very limited studies have focused their attention on more basic aspects of hearing such as sensitivity, i.e., the identification of minimal intensity thresholds across different frequencies. Most previous studies relied on electrophysiological methods for audiograms for dogs, but these methods are considered less accurate than assessments based on behavioral responses. To our knowledge, only one study has established hearing thresholds using a behavioral assessment on four dogs but using a method that did not allow potential improvement throughout the sessions. In the present study, we devised an assessment procedure based on a staircase method. Implying the adaptation of the assessed intensity on the dogs’ performance, this approach grants several assessments around the actual hearing threshold of the animal, thereby increasing the reliability of the result. We used such a method to determine hearing thresholds at three frequencies (0.5, 4.0, and 20.0 kHz). Five dogs were tested in each frequency. The hearing thresholds were found to be 19.5 ± 2.8 dB SPL at 0.5 kHz, 14.0 ± 4.5 dB SPL at 4.0 kHz, and 8.5 ± 12.8 dB SPL at 20.0 kHz. No improvement in performance was visible across the procedure. While the thresholds at 0.5 and 4.0 kHz were in line with the previous literature, the threshold at 20 kHz was remarkably lower than expected. Dogs’ ability to produce vocalization beyond 20 kHz, potentially used in short-range communication, and the selective pressure linked to intraspecific communication in social canids are discussed as potential explanations for the sensitivity to higher frequencies

Dogs’ ability to follow temporarily invisible moving objects: the ability to track and expect are shaped by experience.

Visually tracking a moving object, even if it becomes temporarily invisible, is an important skill for animals living in complex environments. However, this ability has not been widely explored in dogs. To address this gap of knowledge and understand how experience contributes to such ability, we conducted two experiments using a violation of expectation paradigm. Dogs were shown an animation of a ball moving horizontally across a screen, passing behind an occluder, and reappearing with a timing that was faster, slower or congruent with its initial speed. In the first experiment, dogs (N=15) were exposed to the incongruent conditions without prior experience, while in the second experiment dogs (N=37) were preliminarily exposed to the congruent stimulus. Dogs of the first experiment did not exhibit a surprise effect in response to the incongruent conditions, suggesting they had not formed an expectation about the timing of reappearance. However, their latency to orient towards the reappearing ball depended on the condition, suggesting they were able, to some extent, to visually keep track of the stimulus’ trajectory. Dogs of the second experiment were surprised when the ball stayed behind the occluder longer than expected, but showed no difference in latency to orient across conditions. This suggests they had overcome the visual-tracking mechanism and had formed an expectation about the timing of reappearance. In conclusion, dogs seem to use a low-level mechanism to keep visual track of a temporarily disappearing moving object, but experience is required to make expectation about its trajectory

Sound Localization Ability in Dogs

The minimum audible angle (MAA), defined as the smallest detectable difference between the azimuths of two identical sources of sound, is a standard measure of spatial auditory acuity in animals. Few studies have explored the MAA of dogs, using methods that do not allow potential improvement throughout the assessment, and with a very small number of dog(s) assessed. To overcome these limits, we adopted a staircase method on 10 dogs, using a two-forced choice procedure with two sound sources, testing angles of separation from 60 degree to 1 degree. The staircase method permits the level of difficulty for each dog to be continuously adapted and allows for the observation of improvement over time. The dogs’ average MAA was 7.6 degree, although with a large inter-individual variability, ranging from 1.3 to 13.2 degree. A global improvement was observed across the procedure, substantiated by a gradual lowering of the MAA and of choice latency across sessions. The results indicate that the staircase method is feasible and reliable in the assessment of auditory spatial localization in dogs, highlighting the importance of using an appropriate method in a sensory discrimination task, so as to allow improvement over time. The results also reveal that the MAA of dogs is more variable than previously reported, potentially reaching values lower than 2 degree. Although no clear patterns of association emerged between MAA and dogs’ characteristics such as ear shape, head shape or age, the results suggest the value of conducting larger-scale studies to determine whether these or other factors influence sound localization abilities in dogs

Canine Behavioral Assessment and Research Questionnaire (C-BARQ): Validation of the Italian Translation

The aim of this study is to develop an Italian translation of the 100-item Canine Behavioral Assessment and Research Questionnaire (C-BARQ) version and to validate its psychometric properties, in order to facilitate systematic, large-scale studies on dog behavior for Italian-speaking dog owners. A total number of 803 responses by dog owners were collected online. Using the Principal Axis Method and Common Factor Analysis with Quartimin oblique rotation (p 0.70), namely: stranger-directed aggression/fear, dog-directed fear, owner-directed aggression, separation-related behavior, chasing, dog-directed aggression, attachment/attention seeking, and elimination problems. Three factors were slightly under the threshold and two had only modest reliability (non-social fear, energy level, touch sensitivity, excitability and trainability). A potential explanation for factors with low reliability is that the composing items do not describe behaviors resulting from homogeneous stimuli or situations. Although our factorial structure resembled in most respects that of the most recently published Canadian version, some important exceptions are present regarding dog rivalry, intraspecific aggression, fear/aggression towards strangers, touch sensitivity and chewing inappropriate objects. Such differences may be due to demographic and/or cultural differences between the sampled populations. Overall, the results suggest that a 62-item Italian C-BARQ can be reliably used in studies on dog behavior