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Brief report: Inverse sex effects on performance of domestic dogs (Canis familiaris) in a repeated problem-solving task

  • Université Sorbonne Paris Nord

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The authors investigated differences between female and male pet dogs in physical cognition using an object manipulation task. Subjects (24 females and 23 males of different breeds) had to open a box in order to obtain a food reward during 3 consecutive trials, and latency times before success were measured. Males were significantly more successful in opening the box during the first trial. However, this sex difference was inversed when successful individuals were retested. During the following 2 trials, females were more successful than males, indicating that they were able to improve their skills more quickly once they had managed to succeed for a first time. Sex-specific dynamics in repeated problem-solving tasks might be an important contributor to individual differences in cognitive performance of pet dogs.
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Inverse Sex Effects on Performance of Domestic Dogs (Canis Familiaris)
in a Repeated Problem-Solving Task
Charlotte Duranton
Laboratory of Experimental and Comparative Ethology EA4443,
University of Paris 13, Sorbonne Paris Cité, France and
Association Aide aux Vieux Animaux (AVA),
Cuy-Saint-Fiacre, France
Heiko G. Rödel
Laboratory of Experimental and Comparative Ethology EA4443,
University of Paris 13, Sorbonne Paris Cité, France
Thierry Bedossa
Association Aide aux Vieux Animaux (AVA),
Cuy-Saint-Fiacre, France
Séverine Belkhir
Laboratory of Experimental and Comparative Ethology EA4443,
University of Paris 13, Sorbonne Paris Cité, France and
Association Aide aux Vieux Animaux (AVA),
Cuy-Saint-Fiacre, France
The authors investigated differences between female and male pet dogs in physical cognition using an object
manipulation task. Subjects (24 females and 23 males of different breeds) had to open a box in order to obtain
a food reward during 3 consecutive trials, and latency times before success were measured. Males were
significantly more successful in opening the box during the first trial. However, this sex difference was
inversed when successful individuals were retested. During the following 2 trials, females were more
successful than males, indicating that they were able to improve their skills more quickly once they had
managed to succeed for a first time. Sex-specific dynamics in repeated problem-solving tasks might be an
important contributor to individual differences in cognitive performance of pet dogs.
Keywords: sex difference, pet dog, dog cognition, physical cognition, object manipulation
Supplemental materials:
Females and males differ in several aspects of their cognitive
abilities to solve physical problems (Healy, Bacon, Haggis, Harris,
& Kelley, 2009). For example, it has been shown that men perform
better in mental rotation or navigation, whereas women outperform
men in object location memory tasks (Andreano & Cahill, 2009;
Caplan, Crawford, Hyde, & Richardson, 1997). Similar differences
are also found in many nonhuman animals, for instance in rodents
(Hawley, Grissom, Barratt, Conrad, & Dohanich, 2012; Jonasson,
2005). These differences are still not fully understood and are
subject to controversial discussions. One of the widely accepted
explanations is the “range size hypothesis,” proposing that males
are under high selection pressure to remember landmarks as they
have larger home ranges than females, thus leading to an improve-
ment in their physical and spatial cognitive abilities (Healy et al.,
2009). However, in some other taxa such as canids, home range
does not appear to differ between males and females (e.g., Kamler
& MacDonald, 2014). And in free-ranging dogs (Canis familiaris)
sex does not influence home range size (Daniels, 1983) or disper-
sal distance (Pal, Ghosh, & Roy, 1998) either. Moreover, little is
known about the presence or absence of the above-mentioned
sex-specific cognitive differences in the domestic dog (Marshall-
Pescini, Barnard, Branson, & Valsecchi, 2013; Miklósi, 2007;
Passalacqua, Marshall-Pescini, Merola, Palestrini, & Prato Pre-
vide, 2013). This is particularly surprising because various aspects
of dog cognition were intensively studied during the last decades
(reviewed in Bensky, Gosling, & Sinn, 2013). A recent study
focusing on this subject showed that female dogs were more likely
than males to respond to violations of the expected size of an
object (Müller, Mayer, Dörrenberg, Huber, & Range, 2011). But to
This article was published Online First September 1, 2014.
Charlotte Duranton, Laboratory of Experimental and Comparative
Ethology EA4443, University of Paris 13, Sorbonne Paris Cité, France and
Association Aide aux Vieux Animaux (AVA), Cuy-Saint-Fiacre, France;
Heiko G. Rödel, Laboratory of Experimental and Comparative Ethology
EA4443, University of Paris 13; Thierry Bedossa, AVA Association;
Séverine Belkhir, Laboratory of Experimental and Comparative Ethology
EA4443, University of Paris 13 and AVA Association.
We are grateful to all owners and their dogs who volunteered in this
study. We also sincerely thank Cécile Arnault, who carried out the reli-
ability coding. Finally, we thank the staff of the Veterinary School of
Maisons-Alfort and especially Karine Reynaud for kindly lending us the
room for experimentation. Charlotte Duranton is now affiliated with Lab-
oratory of Cognitive Psychology UMR7290, Marseille, France.
Correspondence concerning this article should be addressed to Char-
lotte Duranton, Laboratory of Cognitive Psychology UMR 7290, Uni-
versity of Aix-Marseille, 13 331 Marseille Cedex 03, France. E-mail:
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This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
Journal of Comparative Psychology © 2014 American Psychological Association
2015, Vol. 129, No. 1, 8487 0735-7036/15/$12.00
the best of our knowledge, so far no study has focused on whether
female and male dogs differ in their success to solve a physical
cognitive problem.
In this article, we proposed to explore this understudied field,
testing for sex differences in the domestic dog using a problem-
solving task, defined as “the use of a novel means to reach a goal
when direct means are unavailable” (Seed & Call, 2010). To this
end, subjects had to repeatedly open a box in order to obtain food
and we studied their performance with respect to latency time until
success. Based on the results of studies in other mammalian
species (Healy et al., 2009), we expected that male dogs will
outperform females during a repeated problem-solving task as
applied here. Furthermore, we studied whether this purported male
advantage was constant across time, that is, when initially success-
ful animals were retested in consecutive trials.
Subjects and Experimental Setting
We tested 47 pet dogs (24 females and 23 males) of 28 different
breeds or mixed breeds, with sex ratio balanced across breeds (see
Table S1 in the online supplemental materials). Subjects were
between 1- and 8-years-old (on average: 3.7 years; no significant
age differences between males and females: t .26, p .79), and
did not show any signs of visual or physical impairment. Owners
participated on a voluntary basis and were recruited via the Inter-
net and by personal communication. As verified by interviews with
the owners, all dogs were naïve to the kind of problem-solving task
used in this study.
Experiments were conducted in a closed and silent room (5.0
4.6 m). The experimenter was always the same woman for all dogs
(see Figure S2 in the online supplemental materials). Owners were
present during the experiments, but remained silent, immobile and
did not directly look at their dogs. Furthermore, owners wore dark
sunglasses to avoid giving any gaze cue to the dogs during the
trials. During the experiments, dogs wore their usual collars or
The apparatus consisted of a wooden box (15 cm 15 cm 5
cm), not fixed to the ground. A food reward was hidden inside the
box (a handful of mince and cooked chicken meat), which was
then closed by a plastic cover. A handle (3 cm 3 cm cylindrical
plastic stick) fixed on the top of the cover, allowed the dogs to
remove it (with mouth or front paw) in order to get the reward.
General Procedure and Data Collection
The procedure consisted of two consecutives phases:
1. Familiarization phase: The owner, the dog and the ex-
perimenter entered the room and the dog got unleashed in
order to allow it to explore the room and to get familiar
with the experimenter.
2. Testing phase: The owner and the dogs were on their
predefined location (see Figure S2 in the online supple-
mental materials time until success within each trial were
noted.time until success within each trial were noted.),
with the empty apparatus (i.e., no reward inside) placed
on the floor in front of them. The experimenter attracted
the dog’s attention and let it smell the reward she had in
the hand. Then she put the meat inside the box, and put
the cover on it to close the apparatus, with clear and large
gestures, to ensure that the dog could observe and be
interested in it. Finally, the experimenter went to her own
predefined location and asked the owner to unleash the
dog. This was repeated three times (Trials 1–3). The
experiment was terminated (whether or not the dog was
successful in opening the box) after 120 s during Trial 1,
and after 60 s during Trials 2 and 3. The dog was leashed
at the end of a trial and waited 30 s between each trial.
All trials were video recorded and videos were analyzed by the
same experimenter. For all trials, analysis began when the dog was
unleashed. From this moment on, latency time before first contact
with the box, the dogs’ success in opening the box (yes/no) and the
latency time until success within each trial were noted. See online
supplement materials for details on validation of accuracy of video
Statistical Analysis
Analyses were done using the program R, version 3.0.1 (R Core
Team, 2013). Differences between females and males with respect
to the latency time in approaching the box were tested by linear
mixed-effects models (LMM). Sex differences with respect to the
time to open the box were tested using Cox proportional hazards
regression models. By the latter analysis, we adjusted for the
censored character of the data, that is, that some of the dogs did not
manage to open the box during the respective trials. See the online
supplemental materials for details.
To test for sex-specific differences in the success in opening the
box across time (see Figure 1), we considered data from all
individuals during the first trial. This was done in order to test for
sex-specific differences in success in a novel problem solving task.
During the following trials, we only considered individuals for
analysis, which were successful during at least one of the previous
trials. This was done in order to test whether the probability of
repeated success (i.e., in an already mastered problem-solving
task) differs between females and males. Thus sample size de-
creased between trial one and the following trials, however slightly
increased between Trial 2 and Trial 3, as some animals were
successful during Trial 2 but not during Trial 1.
Latency to Approach the Box
The latency of approaching the object did not differ between
females and males and was not affected by the reproductive status
(neutered/intact) or the age of the dogs, either when considering all
individuals or only focusing on dogs which were successful during
the respective trial (p .05). Furthermore, there was no significant
interaction between sex and trial, indicating that there were no sex
specific differences among trials (p .10).
The latency of approach differed significantly across trials
7.60, n 141, p .022) when considering all
individuals. Post hoc comparisons revealed that latencies during
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the third trial (on average 7.9 s 4.1 CI
) were significantly
higher than during the first trial (4.8 s 4.3 CI
p .020) and during the second trial (5.2 s 3.5 CI
6.16, p .013). The first and second trials did not differ (
p .70). These differences among trials disappeared when only
considering subjects, which were successful during the respective
trial (Trial 1: 1.5 s .7 CI
; Trial 2: 1.3 s .2 CI
; Trial 3:
1.3 s .2 CI
.32, p .85).
Opening the Box
First trial. During the first trial males were significantly more
successful than females in opening the box (Cox proportional
hazards regression:
7.67, n 47, p .006; Figure 1A). Note
that this kind of model integrates the latency time as well as the
probability of success as dependent variable for analysis. There
were no significant effects of the dogs’ age and reproductive status
.08, p .77) with respect to their success (
.11, p .74)
and also no significant interactions among the three predictor
variables (p .10).
Repeated trials. The sex-dependent performance was in-
versed when successful subjects were repeatedly tested in a second
and third trial. During Trial 2 (
4.10, n 21, p .043; Figure
1B) as well as during Trial 3 (
7.40, n 26, p .007; Figure
1C) the proportion of successful females was significantly higher
than the proportion of successful males. Again, there were no
significant effects of age and of reproductive status, and also the
interactions between the 3 predictor variables were not significant
(p .05).
Although sex differences in physical problem-solving skills
have been intensively studied in various mammalian species (Seed
& Call, 2010), to our knowledge this is the first study reporting
differences between females and males in problem-solving abili-
ties in the domestic dog. Most importantly, our results indicate
inversed sex-specific differences in success across repeated trials.
During the first trial, males outperformed females and such a male
advantage in physical cognition is in line with previous findings in
other mammals (Benson-Amram, Weldele, & Holekamp, 2013;
Healy et al., 2009). This initial difference was unlikely due to
females’ lower degree of motivation because both sexes did not
differ in their latency to approach the box in any of the trials. We
suggest that male dogs were less affected by the experimental
setting as studies on dog temperament using nonsocial objects
have frequently reported comparatively higher boldness scores in
males in such situations (Starling et al., 2013).
Different nonexclusive mechanisms might be considered in or-
der to explain this observed sex difference (Müller et al., 2011).
First and as already mentioned, sex-specific selection might have
led to different cognitive abilities. It is possible that such differ-
ence was selected and present in dogs’ and wolves’ common
ancestor. And even if no evidence exists that different selective
pressures, home range size or breeding strategies have shaped male
and female pet dogs’ behavior in a contrasting way (Miklósi,
2007), sex-specific cognitive abilities might originate from the
dog’s ancestral species. Second, sex-specific environment during
ontogeny might have induced different cognitive capacities of
adult females and males. And indeed, sex-specific differences in
early developmental environment are for example reported in
humans, since children of different gender are frequently raised
in a different way according to cultural traditions (Wood & Eagly,
2012). As many owners consider their dogs as family members
(Archer, 1997), a “social gender consideration,” that is, differences
in the way owners might interact with female and male dogs, could
be potentially relevant here. Third, sex difference in cognition
might also be a by-product of other sex-dependent differences,
such as hormone levels (Kimura, 1999). For example, a study in
men indicates that increased testosterone levels have differential
effects on spatial abilities and verbal fluency (O’Connor, Archer,
Hair, & Wu, 2001). But in general, the interaction between tes-
tosterone levels and cognitive abilities is far from being clear.
Most importantly, when retesting individuals that were initially
successful, females outperformed males during these successive
trials. Such a higher performance in female dogs as compared with
males has been already reported in previous studies, although
Figure 1. Kaplan-Meier curves showing the increase in the proportion of successful females and males during
repeated trials. Differences between females and males were significant during all trials; but note the inversed
effects between the first and the following trials. Sample sizes increase from the second to the third trial, as we
considered all individuals for analysis during the repeated trials, which were successful in one of the previous
trials. See text for details on statistics. See the online article for the color version of this figure.
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This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
never in the context of repeated trials (Müller et al., 2011; Rooi-
jakkers et al., 2009). We propose that this inversed sex effect
across time could be due to sex-specific differences in the way of
remembering the successful strategy of problem solving. Indeed,
such differences in learning performance between males and fe-
males in social as well as in nonsocial contexts have been de-
scribed in primates. For example, female rhesus monkeys (Macaca
mulatta) outscored males in a learning task related to the utiliza-
tion of local markers (Herman & Wallen, 2007). Moreover, studies
in humans indicate that females remember precise object or local
features better than males (Lejbak et al., 2009; Voyer et al., 2007).
We propose that similar sex-specific processes could be present in
the dog.
Although this study only focuses on a single task, it provides a
significant piece of evidence emphasizing the existence of sex-
specific differences in problem-solving skills in the domestic dogs.
Most importantly, the study reveals that the direction of differ-
ences between males and females is not necessarily stable across
repeated trials. We hope that our findings will stimulate others to
include such interactive changes across time in the study of cog-
nitive abilities in mammals and birds.
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Received February 27, 2014
Revision received July 28, 2014
Accepted July 30, 2014
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... Dogs do solve the simplest stringpulling tasks, with strings leading directly to the target object; where they fail is with multiple strings placed obliquely, or crossing each other (Osthaus et al., 2005); and a string-pulling experiment with vertically hanging ropes gave more positive results than the usual horizontal string situation (Hiestand, 2011)-though wolves in the same situation did better than dogs. Dogs have done relatively well at spontaneously solving simple container-opening problems (Duranton, Rodel, Bedossa, & Belkhir, 2015). Tasks involving the location and nature of hidden objects are generally solved well, though not necessarily with any understanding of a hidden object's trajectory (e.g., Collier-Baker et al., 2004). ...
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The great increase in the study of dog cognition in the current century has yielded insights into canine cognition in a variety of domains. In this review, we seek to place our enhanced understanding of canine cognition into context. We argue that in order to assess dog cognition, we need to regard dogs from three different perspectives: phylogenetically, as carnivoran and specifically a canid; ecologically, as social, cursorial hunters; and anthropogenically, as a domestic animal. A principled understanding of canine cognition should therefore involve comparing dogs’ cognition with that of other carnivorans, other social hunters, and other domestic animals. This paper contrasts dog cognition with what is known about cognition in species that fit into these three categories, with a particular emphasis on wolves, cats, spotted hyenas, chimpanzees, dolphins, horses, and pigeons. We cover sensory cognition, physical cognition, spatial cognition, social cognition, and self-awareness. Although the comparisons are incomplete, because of the limited range of studies of some of the other relevant species, we conclude that dog cognition is influenced by the membership of all three of these groups, and taking all three groups into account, dog cognition does not look exceptional.
... Finally, apart from the sex differences in dogs framed in a naturalist context, there are other dog-specific sex differences that require deeper exploration. One example is personality traits, such as excitability, in which females tend to be more excitable than males [123,124], distractibility, which shows an opposite trend [123,126], and cognitive abilities, in which males are reported to be smarter in a study on problem-solving [230]. ...
In this paper, we review the scientific reports of sex-related differences in dogs as compared to the outcomes described for wild animals. Our aim was to explore whether the differences in male and female dogs were affected by the domestication process, in which artificial selection is the main driver. For this purpose, we used information regarding personality traits, cognitive processes, and perception, for which there is a wide theoretical framework in behavioral ecology. Aggressiveness and boldness, described as a behavioral syndrome, were reported as being higher in males than females. Females also seemed more inclined to interspecific social interactions with humans in tasks that require cooperative skills, whereas males appeared more inclined to social play, thus implying different levels of social engagement between the sexes, depending on the context. Studies on cognitive processes underlined a greater flexibility in resorting to a particular navigation strategy in males. Most lateralization studies seem to support the view that males are preferentially left-handed and females are preferentially right-handed. Reports on visual focusing coherently rank females as superior in focusing on single social and physical stimuli. Only male dogs are able to discriminate kin; however, the timing of the olfactory recording in sexes is related to the stimulus relevance. Dogs are largely in line with life-history theories, which indicate that sex differences in dogs are mainly rooted in their biological and evolutionary heritage, remaining unchanged despite artificial selection. In contrast, the higher intraspecific sociability in wild male animals was not replicated in dogs.
... Sex differences in cognitive performance have also been found in some set-ups, with male dogs performing better when presented with a novel manipulation task (Duranton et al. 2015) and female dogs being more sensitive towards size constancy violation (Müller et al. 2011). ...
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A fundamental precept of the scientific method is reproducibility of methods and results, and there is growing concern over the failure to reproduce significant results. Family dogs have become a favoured species in comparative cognition research, but they may be subject to cognitive differences arising from genetic (breeding lines) or cultural differences (e.g. preferred training methods). Such variation is of concern as it affects the validity and generalisability of experimental results. Despite its importance, this problem has not been specifically addressed to date. Therefore, we aimed to test the influence of three factors on reproducibility: testing site (proximal environment), breed and sex (phenotype). The same experimenter tested cognitive performance by more than 200 dogs in four experiments. Additionally, dogs’ performance was tested in an obedience task administered by the owner. Breed of dog and testing site were found to influence the level of performance only mildly, and only in a means-end experiment and the obedience task. Our findings demonstrate that by applying the same test protocols on sufficiently large samples, the reported phenomena in these cognitive tests can be reproduced, but slight differences in performance levels can occur between different samples. Accordingly, we recommend the utilisation of well-described protocols supported by video examples of the whole experimental procedure. Findings should focus on the main outcome variables of the experiments, rather than speculating about the general importance of small or secondary performance outcomes which are more susceptible to random or local noise.
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In this thesis I explore the extent to which researchers of animal cognition should be concerned about the reliability of its scientific results and the presence of theoretical biases across research programmes. To do so I apply and develop arguments borne in human psychology’s “replication crisis” to animal cognition research and assess a range of secondary data analysis methods to detect bias across heterogeneous research programmes. After introducing these topics in Chapter 1, Chapter 2 makes the argument that areas of animal cognition research likely contain many findings that will struggle to replicate in direct replication studies. In Chapter 3, I combine two definitions of replication to outline the relationship between replication and theory testing, generalisability, representative sampling, and between-group comparisons in animal cognition. Chapter 4 then explores deeper issue in animal cognition research, examining how the academic systems that might select for research with low replicability might also select for theoretical bias across the research process. I use this argument to suggest that much of the vociferous methodological criticism in animal cognition research will be ineffective without considering how the academic incentive structure shapes animal cognition research. Chapter 5 then beings my attempt to develop methods to detect bias and critically and quantitatively synthesise evidence in animal cognition research. In Chapter 5, I led a team examining publication bias and the robustness of statistical inference in studies of animal physical cognition. Chapter 6 was a systematic review and a quantitative risk-of-bias assessment of the entire corvid social cognition literature. And in Chapter 7, I led a team assessing how researchers in animal cognition report and interpret non-significant statistical results, as well as the p-value distributions of non-significant results across a manually extracted dataset and an automatically extracted dataset from the animal cognition literature. Chapter 8 then reflects on the difficulties of synthesising evidence and detecting bias in animal cognition research. In Chapter 9, I present survey data of over 200 animal cognition researchers who I questioned on the topics of this thesis. Finally, Chapter 10 summarises the findings of this thesis, and discusses potential next steps for research in animal cognition.
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Scientific disciplines face concerns about replicability and statistical inference, and these concerns are also relevant in animal cognition research. This paper presents a first attempt to assess how researchers make and publish claims about animal physical cognition, and the statistical inferences they use to support them. We surveyed 116 published experiments from 63 papers on physical cognition, covering 43 different species. The most common tasks in our sample were trap-tube tasks (14 papers), other tool use tasks (13 papers), means-end understanding and string-pulling tasks (11 papers), object choice and object permanence tasks (9 papers) and access tasks (5 papers). This sample is not representative of the full scope of physical cognition research; however, it does provide data on the types of statistical design and publication decisions researchers have adopted. Across the 116 experiments, the median sample size was 7. Depending on the definitions we used, we estimated that between 44% and 59% of our sample of papers made positive claims about animals’ physical cognitive abilities, between 24% and 46% made inconclusive claims, and between 10% and 17% made negative claims. Several failures of animals to pass physical cognition tasks were reported. Although our measures had low inter-observer reliability, these findings show that negative results can and have been published in the field. However, publication bias is still present, and consistent with this, we observed a drop in the frequency of p-values above .05. This suggests that some non-significant results have not been published. More promisingly, we found that researchers are likely making many correct statistical inferences at the individual-level. The strength of evidence of statistical effects at the group-level was weaker, and its p-value distribution was consistent with some effect sizes being overestimated. Studies such as ours can form part of a wider investigation into statistical reliability in comparative cognition. However, future work should focus on developing the validity and reliability of the measurements they use, and we offer some starting points.
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Affiliation between interacting partners is associated with a high level of behavioural synchronization in many species. Pet dogs are known to share strong affiliative bonds with their owners and to synchronize their behaviour with them when moving freely indoors. Surprisingly, outdoor dog–human interspecific synchronization has seldom been investigated. We therefore explored whether, when allowed to move freely in a familiar outdoor space, dogs synchronize their behaviour with their owners’ movements. We found that dogs visibly synchronized both their location (staying in close proximity) and their activity (moving when their owner moved, and at the same pace, and standing still when their owner stood still) with those of their owners. By demonstrating that owners act as attractors for their dogs in an outdoor space, the present study contributes new data to the understanding of interspecific behavioural synchronization.
When confronted with an unfamiliar object or person, privately owned pet dogs engage in social referencing, synchronizing their reaction with that of their owners. The question of whether shelter dogs do so when confronted with a stranger has not yet been studied. We tested the reactions of 30 shelter dogs with their principal caregiver when confronted with a stranger approaching them in a neutral manner. The caregivers were instructed to behave in one of three ways toward the stranger: stay still, approach, or retreat. The shelter dogs showed both referential looks and gaze alternations between the stranger and their caregiver. However, the shelter dogs did not modify their reactions towards the stranger in accordance with the behaviour of their caregivers. Thus, when confronted with a stranger, shelter dogs did not show social referencing with their handlers, contrary to privately owned pet dogs with their owners. These findings highlight social deprivation that dogs in shelters are confronted with, and emphasize the importance of the affiliative bond between humans and dogs in creating social referencing.
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In humans and in other animal species anxiety-related problems are associated with poor performance in different abilities ranging from decision-making, visual attention, learning and memory. Despite the increasing number of dogs showing anxiety-related problems, the relationship between cognitive performance and behavioural problems has not been investigated so far in this species. In the current study 25 adult dogs with a diagnosis of anxiety-related problems and 21 dogs with no behavioural problems were tested using the classic unsolvable task paradigm, to evaluate both independent problem solving abilities and the propensity of dogs to seek human intervention. Results showed that dogs with anxiety-related problems (ARP) took longer to solve the task in the initial solvable trial (P=0.001) and showed more stress-related behaviours in this trial (P = 0.037) compared to dogs in the control group
This new volume in the Counterpoints series not only summarizes and addresses the validity (or invalidity) of research into gender differences, it also questions the ideology behind this research, and its consequences.
The main aim of this book is to provide a basis for a complete dog behavioural biology based on concepts derived from contemporary ethology. Thus, dog behaviour is viewed from both functional (evolution and ecology) and mechanistic and developmental points of view. The study of dogs is placed in a comparative context which involves comparison with their ancestors (wolves), as well as with humans with which dogs share their present environment. Instead of advocating a single theory which would explain the emergence of dogs during the last 20,000 years of human evolution, this book gives an overview of present knowledge which has been collected by scientists from various fields. It aims to find novel ways to increase our understanding of this complex evolutionary process by combining different methods originating from different scientific disciplines. This is facilitated by describing complementing knowledge provided by various field of science, including zooarchaeology, cognitive and comparative ethology, human-animal interaction, behaviour genetics, behavioural physiology and development, and behavioural ecology. This interdisciplinary approach to the study of dogs deepens our biological understanding of dog behaviour, but also utilizes this knowledge to reveal secrets to behavioural evolution in general, even with special reference to the human species.
The behavior of women and men varies greatly depending on situations, cultures, and historical periods. This flexibility emerges as men and women tailor their division of labor to local ecological and socioeconomic demands. The resulting division is supported by childhood socialization practices that, in interaction with sex differences in child temperament, help boys and girls to develop psychologies suited to their likely adult activities. Although responsive to local conditions, the division of labor is constrained by women's childbearing and nursing of infants and men's size and strength. Because these biological characteristics influence the efficient performance of many activities in society, they underlie central tendencies in the division of labor as well as its variability across situations, cultures, and history. Gender roles-that is, shared beliefs about the traits of women and men-track the division of labor because people infer these traits from their observations of the sexes' behaviors. Social perceivers often essentialize these traits by regarding them as inherent in the biology or social experience of women and men. Gender role expectations, which tend to be consensual within cultures, influence behavior through proximal social psychological and biological processes, whereby (a) other people encourage gender-typical behavior and individuals conform to their own gender identities and (b) hormonal, reward, and cardiovascular mechanisms enable masculine and feminine behaviors.
We monitored 20 cape foxes (Vulpes chama) to determine the social organization, survival, and dispersal of this species on two sites in South Africa from 2005 to 2008. Cape foxes were socially monogamous and territorial, with annual home ranges of mated pairs (n = 8) overlapping 80% on average, compared to a mean overlap of 3% between foxes in adjacent ranges. At least 2 pairs remained associated for >1 breeding season, and both sexes exhibited strong site fidelity, as home ranges in consecutive years overlapped 58–98%. Members of mated pairs never foraged together, however they used the same or nearby (<100 m apart) day rests 81% of the time when pups were 0–4 months of age, but only 28% of the time during other months of the year. Dispersal was male biased, as all juvenile males (n = 6) dispersed when 9–11.5 months old, whereas 3 of 4 juvenile females remained philopatric as either breeders or non-breeding associates. At least 6 foxes bred as yearlings (3 F, 3 M), indicating cape foxes have high reproductive potential. Two adult females maintained their territories after their mates died, whereas two adult males dispersed soon after their mates died, indicating cape foxes likely have a female-based social organization. Annual survival was 0.64, and predation from larger carnivores, primarily black-backed jackals (Canis mesomelas), was responsible for 71% of mortalities. Our results provided empirical support for previous hypotheses regarding the relationship between body size and life-history patterns in Canidae, as several ecological parameters of cape foxes were similar to that of other small (<6 kg) canid species, especially Vulpes species inhabiting arid and semi-arid environments.
Driven by both applied and theoretical goals, scientific interest in canine cognition has experienced a rapid surge in popularity, especially over the last 15 years. Here we provide the most comprehensive review to date of dog cognition research, capturing all the articles (285) we could find on the subject going back to 1911. We begin by summarizing the general research trends, first documenting the rapid recent growth in dog cognition research (particularly in the domain of social cognition), and then identifying a number of trends in terms of the cognition topics and dog populations studied. Next, we summarize and synthesize the substantive conclusions emerging from research on nonsocial (discrimination learning, object permanence, object learning, categorization, object manipulation, quantitative understanding, spatial cognition, and memory) and social (responses to human cues, perspective taking, dog-human communication, and social learning) cognition. In light of the burgeoning research on individual differences in cognition and on the biological organization of cognitive domains, we highlight the potential impact of these topics on the dog cognition field. Finally, based on our syntheses, we outline some ideas for future research, including recommendations that studies focus on: (1) incorporating multiple sensory modalities (most notably olfaction); (2) using more diverse populations of subjects; (3) replicating studies where current knowledge is based on small study sets or on small samples; (4) identifying fundamental developmental patterns of cognitive development; (5) identifying individual differences in cognitive ability; and (6) identifying potential cognitive constraints (e.g. cognitive abilities that are nonindependent due to pleiotropic biological organization).
The dispersal of free-ranging dogs, Canis familiaris, from the town of Katwa, West Bengal, India, was studied from January 1993 to December 1996. Between January 1993 and September 1996, 315 pups were observed from 64 litters. Pups were born between October and March each year, with a peak between November and January. The mortality rate was 68% during the first 4 months, with 102 individuals surviving to the juvenile stage (4 to 12 months). In case of juveniles, the rate of dispersal was 39.29%, whereas, in case of adults it was 23.33%. Mean (±S.D.) home range size for the non-dispersing dogs was 4.8 (±1.7) ha and for the dispersing dogs was 8.4 (±1.7) ha. Moreover, there were significant seasonal variations in the home range sizes of both non-dispersing and dispersing dogs. Juvenile males were the predominant dispersers. Dispersal occurred in all seasons and dispersal rates did not differ between seasons. However, during late monsoon (September to November), dispersal was greater (P