Domestic dogs (Canis familiaris) use human gestures but not nonhuman tokens to find hidden food.

The authors examined the ability of domestic dogs to use human body cues (gestures) and equivalent-sized nonhuman cues to find hidden food in an object choice paradigm. In Experiment 1 the authors addressed the importance of the human element of the cue, and the effects of size, topography, and familiarity on dogs' success in using cues. Experiment 2 further explored the role of the human as cue-giver, and the impact of a change in the experimenter's attentional state during cue presentation. This included a systematic test of the role inanimate tokens play as cues apart from human placement. Our results indicate that dogs are more sensitive to human cues than equivalent nonhuman cues, and that the size of the cue is a critical element in determining dogs' success in following it. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial encoding of hidden objects in dogs (Canis familiaris).

The authors investigated the type of spatial information that controls domestic dogs' (Canis familiaris) search behavior in a situation in which they have to locate a spatial position where they saw an object move and disappear. In Experiments 1 and 2, the authors manipulated all local and global sources of allocentric spatial information surrounding the hiding location. The results revealed that dogs relied on an egocentric frame of reference. Experiment 3 showed that dogs also encoded allocentric information when egocentric information was irrelevant. The authors conclude that dogs simultaneously encode both egocentric and allocentric spatial information to locate a spatial position, but they primarily base their search behavior on an egocentric frame of reference. The authors discuss under which natural conditions dogs might use these 2 sources of spatial information and detail the nature of spatial egocentric information and the circumstances underlying its use by dogs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Domestic dogs (Canis familiaris) are sensitive to the attentional state of humans.

Twelve domestic dogs (Canis familiaris) were given a series of trials in which they were forbidden to take a piece of visible food. In some trials, the human continued to look at the dog throughout the trial (control condition), whereas in others, the human (a) left the room, (b) turned her back, (c) engaged in a distracting activity, or (d) closed her eyes. Dogs behaved in clearly different ways in most of the conditions in which the human did not watch them compared with the control condition, in which she did. In particular, when the human looked at them, dogs retrieved less food, approached it in a more indirect way, and sat (as opposed to laid down) more often than in the other conditions. Results are discussed in terms of domestic dogs' social-cognitive skills and their unique evolutionary and ontogenetic histories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time-dependent decisions in dogs (Canis familiaris).

Investigated whether the foraging decisions of dogs (Canis familiaris) were time dependent and consistent with a temporal weighting rule (TWR) for maximizing the reliability of information. Dogs were given information about patches whose qualities varied over time. To stimulate natural conditions, interruptions at selected points in foraging were interposed. Patch choices were time dependent and closely matched the predictions of the TWR. Dogs relied on very recent information when available, but with increasing delays they used patch averages. The TWR may be a general solution to problems faced by foragers in variable environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial memory of domestic dogs (Canis familiaris) for hidden objects in a detour task.

Spatial memory of domestic dogs (Canis familiaris) for hidden objects was investigated via a visible displacement problem of object permanence with a detour paradigm. Experiment 1 showed that dogs were able to spontaneously locate a disappearing object in a detour situation. In Experiments 2 and 3, dead reckoning and allocentric spatial information were put in conflict. Results revealed that dogs simultaneously encoded both sources of information when they had to bypass an obstacle to locate a hidden object. Experiment 3 also revealed that, over the course of testing, dogs gradually learned to rely predominantly on allocentric cues when the detour involved several reorientations. The current study reveals that spatial memory of dogs for hidden objects in a detour task was guided by flexibility in processing spatial information. Dogs could simultaneously encode dead reckoning and allocentric information to locate a disappearing object and used them hierarchically according to the complexity of the detour they encountered in the environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral and glucocorticoid responses of adult domestic dogs (Canis familiaris) to companionship and social separation.

Removal of 1 member of a long-standing pair of adult domestic dog (Canis familiaris) kennel mates from the home run for 4 hr had no effect on the behavior or plasma glucocorticoid levels of the remaining dog. When tested in a novel environment, dogs showed increased activity and elevated glucocorticoid levels at the end of the session, but these responses were as large when the dogs were with their kennel mates as when they were alone. However activity and glucocorticoid levels were not elevated if the dogs were exposed to the novel environment in the presence of their human caretaker. Dogs more often were observed in proximity with, and soliciting social behavior from, the human than the kennel mate. These results highlight the importance of human companionship for the domestic dog and point to a difference in the nature of the social relationships of dogs with humans and with conspecifics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incentive contrast in domestic dogs (Canis familiaris).

Dogs (Canis familiaris) trained to receive a preferred food (dry beef liver) from an experimenter learned to maintain a longer gaze on the experimenter than dogs receiving a less preferred food (dog pellets). Dogs downshifted from dry liver to pellets rejected food more frequently than nonshifted controls. Gaze duration also decreased in downshifted dogs below the level of a group always reinforced with pellets. In addition, downshifted dogs tended to move away from the experimenter, adopting a lying down posture. This phenomenon, called successive negative contrast, has been described in analogous experiments with a variety of mammalian species, but has failed to occur in similar experiments with nonmammalian vertebrates. Unlike similar previous observations, the present data were obtained in an environment involving interspecific communication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial memory in dogs (Canis familiaris) on a radial maze.

Working spatial memory in dogs (Canis familiaris) was tested in Experiments 1 and 2 on an 8-arm radial maze. When dogs chose freely among all 8 arms containing food in Experiment 1, they learned to enter all 8 arms with progressively fewer arm visits over trials. In Experiment 2, 2 groups of dogs were forced to visit 4 randomly chosen arms on the maze and then tested for memory of these arm visits using a win-shift rule for 1 group and a win-stay rule for the other group. Dogs performed better with the win-shift rule than with the win-stay rule. In Experiment 3, reference memory was investigated by using a 4-arm maze on which 0, 1, 3, and 6 pieces of food were consistently placed on different arms. Dogs learned to visit the arms with the larger amounts before the arms with the smaller amounts. Dogs’ memory capacity in these studies was found to be surprisingly low. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Search behavior in various breeds of adult dogs (Canis familiaris): Object permanence and olfactory cues.

Human analog tests of object permanence were administered to various breeds of adult dogs (Canis familiaris). Exp 1 showed that the performance of terriers, sporting, and working dogs did not differ. Dogs succeeded in solving invisible displacement problems, but performance was lower than in visible displacement tests. Familiarity with the task had some influence because invisible displacement tests were more successful if they were preceded by visible displacement tests. In Exp 2, odor cues from the target object and the hiding screens were available or were masked. Results confirmed that success was lower in invisible than in visible displacement tests and that these problems were solved on the basis of representation of visual information rather than on the basis of olfactory cues or of local rule learning. Dogs are compared with other species that display Stage 6 object permanence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comprehension of human communicative signs in pet dogs (Canis familiaris).

On the basis of a study by D. J. Povinelli, D. T. Bierschwale, and C. G. Cech (1999), the performance of family dogs (Canis familiaris) was examined in a 2-way food choice task in which 4 types of directional cues were given by the experimenter: pointing and gazing, head-nodding (at target), head turning above the correct container (above target), and glancing only (eyes only). The results showed that the performance of the dogs resembled more closely that of the children in D. J. Povinelli et al.'s study, in contrast to the chimpanzees' performance in the same study. It seems that dogs, like children, interpret the test situation as being a form of communication. The hypothesis is that this similarity is attributable to the social experience and acquired social routines in dogs because they spend more time in close contact with humans than apes do, and as a result dogs are probably more experienced in the recognition of human gestures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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 human's 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. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Do dogs (Canis familiaris) seek help in an emergency?

The question of whether dogs recognize an emergency and understand the need to seek help from a bystander was tested in two experiments. In the first experiment, dogs' owners feigned a heart attack in an open field, and in the second experiment, dogs' owners experienced an accident in which a bookcase fell on them and pinned them to the floor. In these experiments, one or two bystanders were available to which dogs could go for help. The dogs' behavior was taped for 6 min after the owner had fallen and was later scored for the frequency and time the dogs spent performing different behaviors. In no case did a dog solicit help from a bystander. It is concluded that dogs did not understand the nature of the emergency or the need to obtain help. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preference for copying unambiguous demonstrations in dogs (Canis familiaris).

In an earlier study (P. Pongrácz et al., 2001), it was shown that human demonstration significantly enhances the detouring ability of dogs (Canis familiaris) around a V-shaped fence. The authors investigated the effect of the direction of the demonstrated detour and the dogs' detouring experience. They found that dogs' trial-and-error experience influences strongly the direction of the dogs' detours later, even if the demonstrator showed detours along the opposite side of the fence. However, dogs' preferences based on their own experiences were changed when the dogs observed demonstrations only on 1 side of the fence. Dogs with no trial-and-error experience followed the direction of 1-sided demonstrations. The change from dogs' own directions to the demonstrated directions seems not to be due to simple facilitative effects of social experience; the similarity with the demonstrated action depends on complex interactions between individual experience and socially provided information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The magic cup: Great apes and domestic dogs (Canis familiaris) individuate objects according to their properties.

Despite current interest in dog (Canis familiaris) cognition, very little is known about how dogs represent objects and how they compare with other species, such as the great apes. Therefore, we investigated how dogs and great apes (chimpanzees [Pan troglodytes], bonobos [Pan paniscus], orangutans [Pongo pygmaeus], gorillas [Gorilla gorilla]) individuate objects in a classical violation of expectation paradigm. We used a container (magic cup) with a double bottom that allowed us to change the type of food that subjects had seen being placed in the container. Using a 2 × 2 design, we varied whether subjects received a generally preferred food and whether the food was substituted (surprise trials) or not (baseline trials). Apes showed increased begging and looking behaviors and dogs showed increased smelling behavior. Both species stayed near the experimenter more frequently in the surprise trials compared with baseline trials. Both species reacted to positive (i.e., good food substituted for bad food) and negative (i.e., bad food substituted for good food) surprises. These results suggest that apes and dogs were able to individuate objects according to their properties or type in comparable ways. In addition, we looked for frustration and elation effects, but subjects' behaviors were not influenced by the food they saw and which they received in previous trials. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Comparative manipulation-test performance in ten-week-old wolves (Canis lupus) and Alaskan malamutes (Canis familiaris): A Piagetian interpretation.

To compare cognitive complexity in wolves and their direct descendents, 4 10-wk-old Eastern timber wolves and 4 10-wk-old malamutes were presented with a series of puzzle boxes that required them to perform increasingly complex manipulations to extract a food dish. Wolves averaged 5.8 successes in 8 trials, and malamutes averaged 1.5 successes. This difference was significant at the .05 level, which supports H. Frank's (see record 1981-32176-001) theoretical model of wolf and dog information processing. The cognitive demands of each task and consistent group differences in problem-solving strategy are discussed in terms of Piaget's stages of human sensorimotor development. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attachment behavior of adult dogs (Canis familiaris) living at rescue centers: Forming new bonds.

In this study, 60 shelter dogs (Canis familiaris) were observed in the modified version of the Strange Situation Test, which has proved to be a useful method for studying dogs' attachment behavior toward humans (J. Topàl, à. Miklòsi, V. Csònyi, & A. Dòka, 1998). Before testing, 40 dogs were handled 3 times for 10 min. In the test, handled dogs encountered 2 persons: the handler in the role of the owner(OW) and an unfamiliar person (UP), whereas the 20 nonhandled dogs encountered unfamiliar persons in both roles. Dogs in the handled group exhibited more contact seeking with the entering OW, less physical contact with the UP, less frequent following of the leaving UP, and less standing by the door in the presence of the OW. The specific response of the handled dogs toward the handler fulfilled the operational criteria of attachment. In shelter conditions, the remarkable demand for social contact with humans may result in rather fast forming of attachment even in adult dogs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attachment behavior in dogs (Canis familiaris): A new application of Ainsworth's (1969) Strange Situation Test.

Fifty-one owner–dog pairs were observed in a modified version of M. D. S. Ainsworth's (1969) Strange Situation Test. The results demonstrate that adult dogs (Canis familiaris) show patterns of attachment behavior toward the owner. Although there was considerable variability in dogs' attachment behavior to humans, the authors did not find any effect of gender, age, living conditions, or breed on most of the behavioral variables. The human–dog relationship was described by means of a factor analysis in a 3-dimensional factor space: Anxiety, Acceptance, and Attachment. A cluster analysis revealed 5 substantially different classes of dogs, and dogs could be categorized along the secure–insecure attached dimensions of Ainsworth's original test. A dog's relationship to humans is analogous to child–parent and chimpanzee–human attachment behavior because the observed behavioral phenomena and the classification are similar to those described in mother–infant interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dogs (Canis familiaris) learn their owners via observation in a manipulation task.

Eighty-seven pet dogs (Canis familiaris) were involved in an experiment in which they had to solve a task to obtain a ball. After witnessing a full demonstration by their owner (10 times pushing the handle of the box, which released a ball), most dogs preferred to touch the handle sooner and more frequently in comparison with other parts of the box, and they used the handle to get the ball. In contrast dogs in 3 control groups developed their own respective methods. The lack of emergence of the ball and playing after the demonstration did not affect the learning performance strongly. This suggests that in dogs the outcome of a demonstration plays only a restricted role in the manifestation of social learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Human Listeners Are Able to Classify Dog (Canis familiaris) Barks Recorded in Different Situations.

The authors investigated whether human listeners could categorize played-back dog (Canis familiaris) barks recorded in various situations and associate them with emotional ratings. Prerecorded barks of a Hungarian herding dog breed (Mudi) provided the sample. Human listeners were asked to rate emotionality of the vocalization and to categorize the situations on the basis of alternative situations provided on a questionnaire. The authors found almost no effect of previous experience with the given dog breed or of owning a dog. Listeners were able to categorize bark situations high above chance level. Emotionality ratings for particular bark samples correlated with peak and fundamental frequency and interbark intervals. The authors did not find a significant effect of tonality (harmonic-to-noise ratio) on either the emotionality rating or situation categorization of the human listeners. Humans' ability to recognize meaning suggests that barks could serve as an effective means of communication between dog and human. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Landmark-based search memory in the domestic dog (Canis familiaris).

Recent studies have suggested that any animal that relies on landmark-based search memory encodes and uses metric properties of space to navigate. So far, however, metric information provided by landmarks has been predominantly investigated in avian species. In the present study, I investigated whether the domestic dog (Canis familiaris), a mammalian species, encodes the distance and direction from landmarks. Dogs were trained to find a ball hidden next to an array of two distinct landmarks that remained at a constant location in a room from trial to trial. After training, the dogs were occasionally tested on unrewarded conditions where the array was either left in its usual position or shifted laterally, perpendicularly, or diagonally relative to the rear wall of the room. Although the dogs significantly shifted their search as a function of the displacement of the landmarks, they did not search at the predicted coordinates of the goal relative to the shift of the landmarks, suggesting that the global cues available in the testing room were also encoded and used by dogs to locate the position of the goal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)