Head-mounted mobile eye-tracking in the domestic dog: A new method.

Humans rely on dogs for countless tasks, ranging from companionship to highly specialized detection work. In their daily lives, dogs must navigate a human-built visual world, yet comparatively little is known about what dogs visually attend to as they move through their environment. Real-world eye-tracking, or head-mounted eye-tracking, allows participants to freely move through their environment, providing more naturalistic results about visual attention while interacting with objects and agents. In dogs, real-world eye-tracking has the potential to inform our understanding of cross-species cognitive abilities as well as working dog training; however, a robust and easily deployed head-mounted eye-tracking method for dogs has not previously been developed and tested. We present a novel method for real-world eye-tracking in dogs, using a simple head-mounted mobile apparatus mounted onto goggles designed for dogs. This new method, adapted from systems that are widely used in humans, allows for eye-tracking during more naturalistic behaviors, namely walking around and interacting with real-world stimuli, as well as reduced training time as compared to traditional stationary eye-tracking methods. We found that while completing a simple forced-choice treat finding task, dogs look primarily to the treat, and we demonstrated the accuracy of this method using alternative gaze-tracking methods. Additionally, eye-tracking revealed more fine-grained time course information and individual differences in looking patterns.

Searching high and low: domestic dogs' understanding of solidity.

Physical reasoning appears central to understanding how the world works, suggesting adaptive function across the animal kingdom. However, conclusive evidence for inferential reasoning about physical objects is limited to primates. We systematically tested a central feature-understanding of solidity-in domestic dogs, by adapting a validated procedure (the shelf task) previously used to test children and non-human primates. Dogs watched a treat dropped into an apparatus with a shelf either present (treat landing on the shelf) or absent (treat landing on the bottom surface) and chose where to search for it (above or below the shelf). Across four studies (n = 64), we manipulated visual access to the treat trajectory and apparatus interior. Dogs correctly inferred the location of treats using physical cues when the shelf was present (Study 1), and learned rapidly when visual cues of continuity were limited (Study 2), and when the shelf was absent (Study 3). Dogs were at chance when the apparatus was fully occluded, and the presence and absence of the shelf varied across trials within subjects, and showed no evidence of learning (Study 4). The findings of these four studies suggest that dogs may be able to make some inferences using solidity and continuity and do not exhibit proximity or gravity biases. However, dogs did not always search correctly from Trial 1, and failed to search correctly when the rewarded location varied within-subjects, suggesting a role for learning, and possible limits to their ability to make inferences about physical objects.

What's the point? Domestic dogs' sensitivity to the accuracy of human informants.

Dogs excel at understanding human social-communicative gestures like points and can distinguish between human informants who vary in characteristics such as knowledge or familiarity. This study explores if dogs, like human children, can use human social informants' past accuracy when deciding whom to trust. Experiment 1 tested whether dogs would behave differently in the presence of an accurate (vs. inaccurate) informant. Dogs followed an accurate informant's point significantly above chance. Further, when presented with an inaccurate point, dogs were more likely to ignore it and choose the correct location. Experiment 2 tested whether dogs could use informant past accuracy to selectively follow the point of the previously accurate informant. In test trials when informants simultaneously pointed at different locations (only one of which contained a treat), dogs chose the accurate informant at chance levels. Experiment 3 controlled for non-social task demands (e.g. understanding of hidden baiting and occlusion events) that may have influenced Experiment 2 performance. In test trials, dogs chose to follow the accurate (vs. inaccurate) informant. This suggests that like children, dogs may be able to use informants' past accuracy when choosing between information sources.

Control it and it is yours: Children's reasoning about the ownership of living things.

One of the hallmarks of ownership is the right to control one's property. Living beings thus pose an interesting puzzle for ownership, since they have some capacity to decide what happens to themselves-they can direct their own motion, pursue their own goals, and make their own decisions. Recent work has shown that adults consider this autonomy to be the key factor in determining whether a human (or human-like) being can be owned. However, little is known about how children reason about the ownership of living beings. Across three experiments we show that children (ages 4-7) use principles of control and autonomy to reason about the ownership of familiar and novel animals. At all ages tested, children were more likely to say that a typically wild animal (e.g., a bear) was owned if a homeowner had controlled its movements by putting it in a cage, rather than simply standing near it in their yard (Experiment 1). Children also used this cue of control to predict whether novel animals were owned (Experiment 2)-and for these unfamiliar animals, the effect of control was even larger. Finally, Experiment 3 found that children's judgments were not specifically driven by the use of a cage to control the animal, but also extended to animals that inherently had the ability to escape (e.g., fly or jump). These autonomous animals were judged as non-owned, while those that could not escape were judged as owned. The use of these principles was evident at all ages, but became stronger with age, particularly when considering novel animals. These are the first studies, to our knowledge, to investigate the development of reasoning about the ownership of animals, and they suggest that, like adults, children consider autonomy an essential factor in the ownership of living things.

Play and optimal welfare: Does play indicate the presence of positive affective states?

Play is commonly used to assess affective states in both humans and non-human animals. Play appears to be most common when animals are well-fed and not under any direct threats to fitness. Could play and playfulness therefore indicate pre-existing positive emotions, and thence optimal animal welfare? We examine this question by surveying the internal and external conditions that promote or suppress play in a variety of species, starting with humans. We find that negative affective states and poor welfare usually do suppress play (although there are notable exceptions where the opposite occurs). Furthermore, research in children suggests that beyond the frequency or total duration of play, poor welfare may additionally be reflected in qualitative aspects of this heterogeneous behaviour (e.g. display of solitary over social play; and the 'fragmentation' of play bouts) that are often overlooked in animals. There are surprisingly few studies of play in subjects with pre-existing optimal welfare or in unambiguously highly positive affective states, making it currently impossible to determine whether play can distinguish optimal or good welfare from merely neutral welfare. This therefore represents an important and exciting area for future research.

Investigating the Function of Play Bows in Dog and Wolf Puppies (Canis lupus familiaris, Canis lupus occidentalis).

Animals utilize behavioral signals across a range of different contexts in order to communicate with others and produce probable behavioral outcomes. During play animals frequently adopt action patterns used in other contexts. Researchers have therefore hypothesized that play signals have evolved to clarify communicative intent. One highly stereotyped play signal is the canid play bow, but its function remains contested. In order to clarify how canid puppies use play bows, we used data on play bows in immature wolves (ages 2.7-7.8 months) and dogs (ages 2 to 5 months) to test hypotheses evaluated in a previous study of adult dogs. We found that young dogs used play bows similarly to adult dogs; play bows most often occurred after a brief pause in play followed by complementary highly active play states. However, while the relative number of play bows and total observation time was similar between dog and wolf puppies, wolves did not follow this behavioral pattern, as play bows were unsuccessful in eliciting further play activity by the partner. While some similarities for the function of play bows in dog and wolf puppies were documented, it appears that play bows may function differently in wolf puppies in regards to re-initiating play.

Investigating the function of play bows in adult pet dogs (Canis lupus familiaris).

Play bows are a common, highly stereotyped canine behavior widely considered to be a 'play signal,' but only one study has researched their function. Bekoff (1995) found that play bows function as behavioral modifiers to help clarify playful intent before or after easily misinterpretable behaviors, such as bite-shakes. To further examine the function of play bows, the current study analyzed five types of behaviors displayed by the bower and the partner immediately before and after a play bow during dyadic play. We found that play bows most often occurred after a brief pause in play. Synchronous behaviors by the bower and the partner, or vulnerable/escape behaviors by the bower (such as running away) and complementary offensive behaviors by the partner (such as chasing) occurred most often after the play bow. These results indicate that during adult dog dyadic play, play bows function to reinitiate play after a pause rather than to mediate offensive or ambiguous actions.