Nathaniel J. Hall

Megachiropteran bats (Pteropus) utilize human referential stimuli to locate hidden food.

Spontaneous point-following behavior has been considered an indicator of advanced social cognition unique to humans. Recently, it has been suggested that a close evolutionary relationship with humans could result in similar social skills in domesticated species. An alternative view is that the mechanism is not genetic domestication alone but instead a combination of phylogenetic and ontogenetic variables. Here we test the necessity of phylogenetic domestication by investigating the point-following behavior of a captive population of nondomesticated megachiropteran bats (Pteropus pumilus, Pteropus rodricensis, Pteropus conspicillatus, Pteropus vampyrus). Three of five subjects were highly successful in following an unfamiliar humans point to a target location, providing the first empirical evidence of cross-species social referencing in bats. The three successful bats were all born in captivity and socialized to humans early in life, whereas unsuccessful bats were wild-born individuals. This study provides evidence that referential point following is not restricted to domesticated animals and indicates that early experience may be important. Megachiropteran bats may prove to be a useful model for studying social behaviors.

Performance of Pugs, German Shepherds, and Greyhounds (Canis lupus familiaris) on an odor-discrimination task

Public opinion and the scientific literature alike reflect a widespread assumption that there are differences in behavior between dog breeds. Direct empirical behavioral assessments of such differences, however, are rare and have produced mixed results. One area where breed differences are often assumed is olfaction, where German Shepherds, hounds, and Labradors are commonly used for odor-detection work, whereas toy breeds and brachycephalic dogs, such as Pugs, are not. Choice of breed for scent detection work, however, may be driven more by historical choices than data. In this article we directly assessed the ability of German Shepherds, Pugs, and Greyhounds to acquire a simple olfactory discrimination, and their ability to maintain performance when the target odorant was diluted. Our results show that contrary to expectations, Pugs significantly outperformed the German Shepherds in acquiring the odor discrimination and maintaining performance when the odorant concentration was decreased. Nine of 10 Greyhounds did not complete acquisition training because they failed a motivation criterion. These results indicate that Pugs outperformed German Shepherds in the dimensions of olfaction assessed. Greyhounds showed a general failure to participate. Overall, our results highlight the importance of direct behavioral measurement of assumed behavioral breed differences.

Assessment of attachment behaviour to human caregivers in wolf pups (Canis lupus lupus)

Previous research suggested that 16-week old dog pups, but not wolf pups, show attachment behaviour to a human caregiver. Attachment to a caregiver in dog pups has been demonstrated by differential responding to a caregiver compared to a stranger in the Ainsworth Strange Situation Test. We show here that 3-7 week old wolf pups also show attachment-like behaviour to a human caregiver as measured by preferential proximity seeking, preferential contact, and preferential greeting to a human caregiver over a human stranger in a modified and counterbalanced version of the Ainsworth Strange Situation Test. In addition, our results show that preferential responding to a caregiver over a stranger is only apparent following brief isolation. In initial episodes, wolf pups show no differentiation between the caregiver and the stranger; however, following a 2-min separation, the pups show proximity seeking, more contact, and more greeting to the caregiver than the stranger. These results suggest intensive human socialization of a wolf can lead to attachment--like responding to a human caregiver during the first two months of a wolf pups life.

Pavlovian conditioning enhances resistance to disruption of dogs performing an odor discrimination

Domestic dogs are used to aid in the detection of a variety of substances such as narcotics and explosives. Under real-world detection situations there are many variables that may disrupt the dogs performance. Prior research on behavioral momentum theory suggests that higher rates of reinforcement produce greater resistance to disruption, and that this is heavily influenced by the stimulus-reinforcer relationship. The present study tests the Pavlovian interpretation of resistance to change using dogs engaged in an odor discrimination task. Dogs were trained on two odor discriminations that alternated every six trials akin to a multiple schedule in which the reinforcement probability for a correct response was always 1. Dogs then received several sessions of either odor Pavlovian conditioning to the S+ of one odor discrimination (Pavlovian group) or explicitly unpaired exposure to the S+ of one odor discrimination (Unpaired group). The remaining odor discrimination pair for each dog always remained an unexposed control. Resistance to disruption was assessed under presession feeding, a food-odor disruptor condition, and extinction, with baseline sessions intervening between disruption conditions. Equivalent baseline detection rates were observed across experimental groups and odorant pairs. Under disruption conditions, Pavlovian conditioning led to enhanced resistance to disruption of detection performance compared to the unexposed control odor discrimination. Unpaired odor conditioning did not influence resistance to disruption. These results suggest that changes in Pavlovian contingencies are sufficient to influence resistance to change.

Association between increased behavioral persistence and stereotypy in the pet dog.

The aim of the present study was to evaluate whether dogs that exhibit stereotypy also show higher behavioral persistence in an extinction-learning task. Thirteen pet dogs with stereotypy and 13 breed-matched control dogs were assessed on a resistance to extinction test. Each dog was trained for 40 trials using a food reinforcer to nose-touch the experimenters hand on a continuous reinforcement schedule. After acquisition, the dogs entered an extinction phase, during which food was no longer delivered. The numbers of nose-touches as well as inter-response times during this phase were recorded. A linear regression found that stereotypy status (t=-2.46, P=.027) and breed type (t=2.44, P=.023) were significant predictors of the number of responses in extinction. Dogs with stereotypy responded more in extinction than control dogs. The mean number of responses was 13.4 (SD=14.7) in the control group and 26.0 (SD=15.3) in the stereotypy group. These results suggest a link between previous laboratory and zoo animal findings on the neurophysiology of stereotypy and the pet dog population. They also have implications for the use of extinction procedures to reduce stereotypic behaviors in pet dogs, as these dogs show enhanced resistance to extinction.

Behavioral and Self-report Measures Influencing Children's Reported Attachment to Their Dog

ABSTRACT Despite the prevalence of dogs as family pets and increased scientific interest in canine behavior, few studies have investigated charac- teristics of the child or dog that influence the child–dog relationship. In the present study, we explored how behavioral and some self-report measures influence a childs reported attachment to their dog, as assessed by the Lexington Attachment to Pets Scale (LAPS). We tested specifically whether children (n = 99; mean age = 10.25 years, SD = 1.31) reported stronger attachment to dogs that were perceived as being more supportive (mea- sured by a modified version of the Network of Relationships Inventory), that were more successful in following the childs pointing gesture in a standard two-object choice test, or that solicited more petting in a sociability assess- ment. In addition, we assessed whether childrens attachment security to their parent and being responsible for the care of their dog influenced re- ported attachment to the dog. Overall, perceived support provided by the dog was highly predictive of all subscales of the LAPS. The dogs success in following the childs pointing gestures and lower rates of petting during the sociability assessment were associated with higher ratings on the General Attachment subscale of the LAPS, but not on the other subscales. Caring for the dog did not predict the childs reported attachment to the dog, but did predict the dogs behavior on the point-following task and petting during the sociability task. If the child cared for the dog, the dog was more likely to be successful on the pointing task and more likely to be petted. These results indicate a dyadic relationship in which the childs care for the dog is associ- ated with the dogs behavior on the behavioral tasks, which in turn is related to the childs reported attachment to their dog. The direction of influence and nature of this dyad will be a fruitful area for future research.

The influence of breed and environmental factors on social and solitary play in dogs (Canis lupus familiaris)

The domestic dog is an ideal model species in which to study the genetic and environmental factors that influence play behavior. Dogs exist in a wide variety of breeds and frequently engage in multiple forms of play. In the present study, we investigated whether the levels of solitary and social play differed between dogs of three breed types with distinct predatory motor pattern sequences (herding dogs, retrievers, and livestock guarding dogs [LGDs]). Furthermore, we investigated how environmental factors (social and nonsocial contexts) influenced play in dogs of these breed types. Groups of breed-matched dyads with working experience and of equivalent age, sex, and neuter status ratios were exposed to four experimental test conditions and two control conditions in randomized orders. With respect to solitary play, environmental context did have a significant effect, with toys reliably producing the highest levels of solitary play across all breed types. Retrievers engaged in significantly higher levels of solitary play overall than LGDs, and there was a trend in comparison to herding dogs. In contrast, neither environmental context nor breed had a significant effect on social play levels; however, neuter status of the dyads did have a significant effect on social play, with mixed-status dyads engaging in significantly higher levels of social play than same-status dyads. Our findings provide experimental evidence for identifying proximate, environmental stimuli that reliably facilitate social and solitary play and discuss possible genetic (i.e., breed type) and lifetime influences on the form of play in domestic dogs.

Food and Food-Odor Preferences in Dogs: A Pilot Study

Abstract Evaluation of food palatability and preference is of great importance to the pet food industry. One common technique for evaluating palatability is a 2-bowl test in which 2 products are offered simultaneously and food consumption is measured. This yields clear results with dogs trained to routinely conduct such comparisons, but it is less clear how this extends to untrained pet dogs. In addition, prior research indicates that olfaction is important in food preference, but methods for evaluating odor preference in canines are currently lacking. In this study, we developed a modified 2-bowl test for evaluation of food preferences in pet dogs with minimal training, and an olfactometer technique for the evaluation of odor preferences. In our 2-bowl procedure, we observed clear preferences among 4 commercial food products in 6 pet dogs. Across repeated testing, preferences strengthened, but the first evaluation accurately estimated the direction and significance of preference. In addition, dogs typically (89% of the time) consumed more of the food they chose first, suggesting they did not need to taste each food to choose. Our odor preference olfactometer assessment, however, did not reveal odor preferences other than that dogs preferred to sniff a food odor over clean air. Further work will be needed to identify methods of measuring odor preferences amongst food odors for dogs, but the modified 2-bowl test shows promise for further testing in pet dogs.

Cognitive Development in Gray Wolves: Development of Object Permanence and Sensorimotor Intelligence with Respect to Domestic Dogs

In this chapter, we explore whether domestic dogs and gray wolves share a similar cognitive development with regards to how they represent physical and/or social objects. To reach this objective, we examine two key components of the Piagetian theory of cognitive development in the gray wolf: object permanence and sensorimotor intelligence. We detail how the capacity to search and locate disappearing objects develops in wolves and compare these data with those observed in previous studies with dogs. We then further describe an observational study of sensorimotor intelligence with these wolves. Overall, the results suggest that the development of object permanence is similar in dogs and wolves, both species reaching Stage 5b of object permanence by the age of 11 weeks. In terms of sensorimotor intelligence, Stage 4 was the upper limit of sensorimotor intelligence we observed in wolves. Moreover, up to 6 weeks of age, the behaviors of wolf puppies are directed predominantly towards their conspecifics, and by Week 8, wolves’ interest in inanimate object increases significantly. In discussion, we explore the factors affecting the development of object permanence and sensorimotor intelligence in canines.