Identification of Genes Associated with Human-Canine Communication in Canine Evolution.

The dog (Canis familiaris) was the first domesticated animal and hundreds of breeds exist today. During domestication, dogs experienced strong selection for temperament, behaviour, and cognitive ability. However, the genetic basis of these abilities is not well-understood. We focused on ancient dog breeds to investigate breed-related differences in social cognitive abilities. In a problem-solving task, ancient breeds showed a lower tendency to look back at humans than other European breeds. In a two-way object choice task, they showed no differences in correct response rate or ability to read human communicative gestures. We examined gene polymorphisms in oxytocin, oxytocin receptor, melanocortin 2 receptor, and a Williams–Beuren syndrome-related gene (WBSCR17), as candidate genes of dog domestication. The single-nucleotide polymorphisms on melanocortin 2 receptor were related to both tasks, while other polymorphisms were associated with the unsolvable task. This indicates that glucocorticoid functions are involved in the cognitive skills acquired during dog domestication.

Horses with sustained attention follow the pointing of a human who knows where food is hidden

When interacting with humans, domesticated species may respond to communicative gestures, such as pointing. However, it is currently unknown, except for in dogs, if species comprehend the communicative nature of such cues. Here, we investigated whether horses could follow the pointing of a human informant by evaluating the credibility of the information about the food-hiding place provided by the pointing of two informants. Using an object-choice task, we manipulated the attentional state of the two informants during food-hiding events and differentiated their knowledge about the location of the hidden food. Furthermore, we investigated the horses’ visual attention levels towards human behaviour to evaluate the relationship between their motivation and their performance of the task. The result showed that horses that sustained high attention levels could evaluate the credibility of the information and followed the pointing of an informant who knew where food was hidden (Z = − 2.281, P = 0.002, n = 36). This suggests that horses are highly sensitive to the attentional state and pointing gestures of humans, and that they perceive pointing as a communicative cue. This study also indicates that the motivation for the task should be investigated to determine the socio-cognitive abilities of animals.

ManyDogs 1: A Multi-Lab Replication Study of Dogs' Pointing Comprehension

To promote collaboration across canine science, address reproducibility issues, and advance open science practices within animal cognition, we have launched the ManyDogs consortium, modeled on similar ManyX projects in other fields. We aimed to create a collaborative network that (a) uses large, diverse samples to investigate and replicate findings, (b) promotes open science practices of preregistering hypotheses, methods, and analysis plans, (c) investigates the influence of differences across populations and breeds, and (d) examines how different research methods and testing environments influence the robustness of results. Our first study combines a phenomenon that appears to be highly robust, dogs’ ability to follow human pointing, with a question that remains controversial: do dogs interpret pointing as an informative gesture, as an imperative command, or as a simple associative cue? We collected preliminary data (N = 61) from a single laboratory on two conditions of a 2-alternative object choice task: (1) Ostensive (experimenter pointed to a baited cup after making eye-contact and saying the dog’s name); (2) Non-ostensive (experimenter pointed to a baited cup without making eye-contact or saying the dog’s name). Dogs followed the ostensive point, but not the non-ostensive point, significantly more often than expected by chance. Preliminary results also provided suggestive evidence for variability in point-following across dog breeds. The next phase is the global participation stage of the project. We propose to replicate this protocol in a large and diverse sample of research sites, simultaneously assessing replicability between labs and further investigating the question of dogs’ point-following comprehension.

The performance of domestic dogs (Canis lupus familiaris) on two versions of the object choice task

Object choice task (OCT) studies are widely used to assess the phylogenetic and ontogenetic distribution of the understanding of communicative cues, with this understanding serving as a proxy for the discernment of communicative intentions. Recent reviews have found systematic procedural and methodological differences in studies which compare performances across species on the OCT. One such difference concerns the spatial configuration of the test set-up, specifically the distances between the two containers (inter-object distance) and the subject–experimenter distance. Here, we tested dogs on two versions of the task: a central version in which the containers were in the subjects’ direct line of vision, and a peripheral version in which the position of the containers was distal to the subject. Half of the subjects were tested with a barrier in the testing environment (as nonhuman primates are tested) and the other half without. We found that dogs tested with a barrier performed significantly better in the central version and were more likely to fail to make a choice in the peripheral version. Dogs tested without a barrier showed comparable performance on the two versions. We thus failed to find support for the distraction hypothesis in dogs. We discuss potential explanations for this, highlighting how methodological differences in the presentation of the OCT can influence outcomes in studies using this paradigm.

Children understand communication intuitively but indirect communication makes them think twice – Evidence from pupillometry and looking patterns

Interpreting a speaker’s communicative acts is a challenge children are facing permanently in everyday live. In doing so, they seem to understand direct communicative acts more easily than indirect communicative acts. The present study investigated which step in the processing of communicative acts might cause difficulties in understanding indirect communication. To assess the developmental trajectory of this phenomenon, we tested 3- and 5-year-old children (N=105) using eyetracking and an object-choice task. The children watched videos that showed puppets during their every-day activities (e.g., pet care). For every activity, the puppets were asked which of two objects (e.g., rabbit or dog) they would rather have. The puppets responded either directly (“I want the rabbit”) or indirectly (“I have a carrot”). Results showed that children chose the object intended by the puppets more often in the direct- than in the indirect-communication condition, and 5-year-olds chose correctly more than 3-year-olds. However, even though we found that children’s pupil size increased while hearing the utterances, we found no effect for communication type before children had already decided on the correct object during object selection by looking at it. Only after this point, that is, only in children’s further fixation patterns and reaction times did differences for communication type occur. Thus, although children’s object-choice performance suggests that indirect communication is harder to understand than direct communication, the cognitive demands during processing both communication types seem similar. We discuss theoretical implications of these findings for developmental pragmatics in terms of a dual-process account of communication comprehension.