1
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Salomons H, Ferrans M, Cusato C, Moore K, Woods V, Bray E, Kennedy B, Block T, Douglas L, Roberts A, Gruen M, Hare B. Longitudinal evidence for the emergence of multiple intelligences in assistance dog puppies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.26.615218. [PMID: 39386489 PMCID: PMC11463349 DOI: 10.1101/2024.09.26.615218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/12/2024]
Abstract
Cognitive test batteries suggest that adult dogs have different types of cognitive abilities that vary independently. In the current study, we tested puppies repeatedly over a crucial period of development to explore the timing and rate at which these different cognitive skills develop. Service dog puppies (n = 113), raised using two different socialization strategies, were either tested longitudinally (n =91) or at a single time point (n = 22). Subjects tested longitudinally participated in the battery every two weeks during and just beyond their final period of rapid brain growth (from approximately 8-20 weeks of age). Control puppies only participated in the test battery once, which allowed us to evaluate the impact of repeated testing. In support of the multiple intelligences hypothesis (MIH), cognitive skills emerged at different points across the testing period, not simultaneously. Maturational patterns also varied between cognitive skills, with puppies showing adult-like performance on some tasks only weeks after a skill emerged, while never achieving adult performance in others. Differences in rearing strategy did not lead to differences in developmental patterns while, in some cases, repeated testing did. Overall, our findings provide strong support for the MIH by demonstrating differentiated development across the cognitive abilities tested.
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2
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Riemer S, Bonorand A, Stolzlechner L. Evidence for the communicative function of human-directed gazing in 6- to 7-week-old dog puppies. Anim Cogn 2024; 27:61. [PMID: 39311933 PMCID: PMC11420273 DOI: 10.1007/s10071-024-01898-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 08/06/2024] [Indexed: 09/26/2024]
Abstract
In human infants, the ability to show gaze alternations between an object of interest and another individual is considered fundamental to the development of complex social-cognitive abilities. Here we show that well-socialised dog puppies show gaze alternations in two contexts at an early age, 6-7 weeks. Thus, 69.4% of puppies in a novel object test and 45.59% of puppies during an unsolvable task alternated their gaze at least once between a person's face and the object. In both contexts, the frequency of gaze alternations was positively correlated with the duration of whimpering, supporting the communicative nature of puppies' gazing. Furthermore, the number of gaze alternations in the two contexts was correlated, indicating an underlying propensity for gazing at humans despite likely different motivations in the two contexts. Similar to humans, and unlike great apes or wolves, domestic dogs show gaze alternations from an early age if they are well-socialised. They appear to have a genetic preparedness to communicate with humans via gaze alternations early in ontogeny, but they may need close contact with humans for this ability to emerge, highlighting the interactive effects of domestication and environmental factors on behavioural development in dogs.
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Affiliation(s)
- Stefanie Riemer
- Messerli Research Institute, Department of Interdisciplinary Life Sciences, Vetmeduni Vienna, Vienna, 1210, Austria.
- Division of Animal Welfare, Vetsuisse Faculty, University of Bern, Bern, 3012, Switzerland.
| | - Alina Bonorand
- Division of Animal Welfare, Vetsuisse Faculty, University of Bern, Bern, 3012, Switzerland
| | - Lisa Stolzlechner
- Department of Behavioral & Cognitive Biology, University of Vienna, Vienna, 1030, Austria
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3
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Garamszegi LZ, Kolm N. The reduction in relative brain size in the domesticated dog is not an evolutionary singularity among the canids. Biol Lett 2024; 20:20240336. [PMID: 39102458 PMCID: PMC11299805 DOI: 10.1098/rsbl.2024.0336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 06/28/2024] [Accepted: 07/01/2024] [Indexed: 08/07/2024] Open
Abstract
Domestication has long been considered the most powerful evolutionary engine behind dramatic reductions in brain size in several taxa, and the dog (Canis familiaris) is considered as a typical example that shows a substantial decrease in brain size relative to its ancestor, the grey wolf (Canis lupus). However, to make the case for exceptional evolution of reduced brain size under domestication requires an interspecific approach in a phylogenetic context that can quantify the extent by which domestication reduces brain size in comparison to closely related non-domesticated species responding to different selection factors in the wild. Here, we used a phylogenetic method to identify evolutionary singularities to test if the domesticated dog stands out in terms of relative brain size from other species of canids. We found that the dog does not present unambiguous signature of evolutionary singularity with regard to its small brain size, as the results were sensitive to the considerations about the ancestral trait values upon domestication. However, we obtained strong evidence for the hibernating common raccoon dog (Nyctereutes procyonoides) being an evolutionary outlier for its brain size. Therefore, domestication is not necessarily an exceptional case concerning evolutionary reductions in brain size in an interspecific perspective.
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Affiliation(s)
| | - Niclas Kolm
- Department of Zoology, Stockholm University, Stockholm, Sweden
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4
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McGrath AP, Horschler DJ, Hancock L. Feline Cognition and the Role of Nutrition: An Evolutionary Perspective and Historical Review. Animals (Basel) 2024; 14:1967. [PMID: 38998079 PMCID: PMC11240355 DOI: 10.3390/ani14131967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/25/2024] [Accepted: 06/30/2024] [Indexed: 07/14/2024] Open
Abstract
Research into cognition in cats and the impact of nutrition on cat cognitive health lags behind that in dogs but is receiving increased attention. In this review, we discuss the evolutionary history of the domesticated cat, describe possible drivers of domestication, and explore the interrelationships between nutrition and cat cognition. While most cat species are solitary, domesticated cats can live in social groups, engage in complex social encounters, and form strong attachments to humans. Researchers have recently started to study cat cognition using similar methods as those developed for dogs, with an initial primary focus on perception and social cognition. Similar to dogs, cats also show cognitive and behavioral changes associated with stress and aging, but these signs are often gradual and often considered a consequence of natural aging. Despite the fundamental role of nutrition in cognitive development, function, and maintenance, research into the association between nutrition and cognition in cats is only preliminary. Ultimately, additional research is needed to gain a full understanding of cat cognition and to explore the role of nutrition in the cognitive health of cats to help improve their welfare.
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5
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Nagasawa M, Tomori S, Mogi K, Kikusui T. Attachment-like behavioral expressions to humans in puppies are related to oxytocin and cortisol: A comparative study of Akitas and Labrador Retrievers. Peptides 2024; 177:171224. [PMID: 38636810 DOI: 10.1016/j.peptides.2024.171224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/13/2024] [Accepted: 04/15/2024] [Indexed: 04/20/2024]
Abstract
This study investigated the relationship between urinary hormone concentrations and attachment-related behaviors in two dog breeds, the Akitas and Labrador Retrievers, to elucidate the hormonal and behavioral mechanisms underlying domestication and interspecies attachment to humans. By measuring cortisol and oxytocin concentrations, and conducting the Strange Situation Test (SST), we aimed to investigate breed differences in endocrine secretions associated with domestication and how these differences influence dog behavior toward humans. Our results showed significant breed differences in urinary cortisol concentrations, with Akitas exhibiting higher levels than Labrador Retrievers. This suggests a breed-specific stress response related to genetic proximity to wolves. However, oxytocin concentrations did not differ significantly, which suggests a complex interplay between factors influencing the domestication process and the formation of attachment behaviors. Behavioral observations during the SST revealed breed-specific patterns, with Labrador Retrievers showing more playful and attachment-like behaviors and Akitas showing more exploratory and passive behaviors. The study found correlations between hormones and behaviors within breeds, particularly in Labrador Retrievers, where oxytocin concentrations were associated with attachment-like behaviors, and cortisol concentrations reflected individual differences in physical activity rather than stress responses to social situations. These findings contribute to the understanding of the evolutionary and adaptive processes underlying the ability of domestic dogs to form close relationships with humans while highlighting the role of hormonal mechanisms in mediating attachment behaviors and the influence of breed-specific genetic backgrounds on these processes.
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Affiliation(s)
- Miho Nagasawa
- Department of Animal Science and Biotechnology, Azabu University, Japan
| | - Sakiko Tomori
- Department of Animal Science and Biotechnology, Azabu University, Japan
| | - Kazutaka Mogi
- Department of Animal Science and Biotechnology, Azabu University, Japan
| | - Takefumi Kikusui
- Department of Animal Science and Biotechnology, Azabu University, Japan.
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6
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Sexton CL, Diogo R, Subiaul F, Bradley BJ. Raising an Eye at Facial Muscle Morphology in Canids. BIOLOGY 2024; 13:290. [PMID: 38785773 PMCID: PMC11118188 DOI: 10.3390/biology13050290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/13/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024]
Abstract
The evolution of facial muscles in dogs has been linked to human preferential selection of dogs whose faces appear to communicate information and emotion. Dogs who convey, especially with their eyes, a sense of perceived helplessness can elicit a caregiving response from humans. However, the facial muscles used to generate such expressions may not be uniquely present in all dogs, but rather specifically cultivated among various taxa and individuals. In a preliminary, qualitative gross anatomical evaluation of 10 canid specimens of various species, we find that the presence of two facial muscles previously implicated in human-directed canine communication, the levator anguli occuli medialis (LAOM) and the retractor anguli occuli lateralis (RAOL), was not unique to domesticated dogs (Canis familiaris). Our results suggest that these aspects of facial musculature do not necessarily reflect selection via human domestication and breeding. In addition to quantitatively evaluating more and other members of the Canidae family, future directions should include analyses of the impact of superficial facial features on canine communication and interspecies communication between dogs and humans.
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Affiliation(s)
- Courtney L. Sexton
- Department of Population Health Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052, USA
| | - Rui Diogo
- Department of Anatomy, Howard University School of Medicine, Washington, DC 20059, USA
| | - Francys Subiaul
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052, USA
- Department of Speech, Language and Hearing Sciences, The George Washington University, Washington, DC 20052, USA
| | - Brenda J. Bradley
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052, USA
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7
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Amici F, Meacci S, Caray E, Oña L, Liebal K, Ciucci P. A first exploratory comparison of the behaviour of wolves (Canis lupus) and wolf-dog hybrids in captivity. Anim Cogn 2024; 27:9. [PMID: 38429445 PMCID: PMC10907477 DOI: 10.1007/s10071-024-01849-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/31/2023] [Accepted: 11/07/2023] [Indexed: 03/03/2024]
Abstract
Extensive introgression of genes from domesticated taxa may be a serious threat for the genomic integrity and adaptability of wild populations. Grey wolves (Canis lupus) are especially vulnerable to this phenomenon, but there are no studies yet assessing the potential behavioural effects of dog-introgression in wolves. In this study, we conducted a first systematic comparison of admixed (N = 11) and non-admixed (N = 14) wolves in captivity, focusing on their reaction to unfamiliar humans and novel objects, and the cohesiveness of their social groups. When exposed to unfamiliar humans in the experimental task, wolves were more vigilant, fearful and aggressive than admixed wolves, and less likely to approach humans, but also more likely to spend time in human proximity. When exposed to novel objects, wolves were more aggressive than admixed wolves, less likely to spend time in object proximity, and more likely to interact with objects, but also less vigilant and as fearful as admixed wolves. Finally, social networks were more cohesive in wolves than in admixed wolves. Although caution is needed when comparing groups of captive individuals with different life experiences, our study suggests that dog admixture may lead to important behavioural changes in wolves, with possible implications for conservation strategies.
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Affiliation(s)
- Federica Amici
- Life Sciences, Institute for Biology, Human Biology and Primate Cognition, Leipzig University, Leipzig, Germany.
- Department of Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
| | - Simone Meacci
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Emmeline Caray
- Department of Life Sciences, University of Strasbourg, Strasbourg, France
| | - Linda Oña
- Life Sciences, Institute for Biology, Human Biology and Primate Cognition, Leipzig University, Leipzig, Germany
| | - Katja Liebal
- Life Sciences, Institute for Biology, Human Biology and Primate Cognition, Leipzig University, Leipzig, Germany
- Department of Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Paolo Ciucci
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
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8
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Ferreira VHB, Lansade L, Calandreau L, Cunha F, Jensen P. Are domesticated animals dumber than their wild relatives? A comprehensive review on the domestication effects on animal cognitive performance. Neurosci Biobehav Rev 2023; 154:105407. [PMID: 37769929 DOI: 10.1016/j.neubiorev.2023.105407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 10/03/2023]
Abstract
Animal domestication leads to diverse behavioral, physiological, and neurocognitive changes in domesticated species compared to their wild relatives. However, the widely held belief that domesticated species are inherently less "intelligent" (i.e., have lower cognitive performance) than their wild counterparts requires further investigation. To investigate potential cognitive disparities, we undertook a thorough review of 88 studies comparing the cognitive performance of domesticated and wild animals. Approximately 30% of these studies showed superior cognitive abilities in wild animals, while another 30% highlighted superior cognitive abilities in domesticated animals. The remaining 40% of studies found similar cognitive performance between the two groups. Therefore, the question regarding the presumed intelligence of wild animals and the diminished cognitive ability of domesticated animals remains unresolved. We discuss important factors/limitations for interpreting past and future research, including environmental influences, diverse objectives of domestication (such as breed development), developmental windows, and methodological issues impacting cognitive comparisons. Rather than perceiving these limitations as constraints, future researchers should embrace them as opportunities to expand our understanding of the complex relationship between domestication and animal cognition.
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Affiliation(s)
- Vitor Hugo Bessa Ferreira
- IFM Biology, AVIAN Behavioural Genomics and Physiology group, Linköping University, 581 83 Linköping, Sweden; INRAE, CNRS, IFCE, Université de Tours, Centre Val de Loire UMR Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France.
| | - Léa Lansade
- INRAE, CNRS, IFCE, Université de Tours, Centre Val de Loire UMR Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France
| | - Ludovic Calandreau
- INRAE, CNRS, IFCE, Université de Tours, Centre Val de Loire UMR Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France
| | - Felipe Cunha
- IFM Biology, AVIAN Behavioural Genomics and Physiology group, Linköping University, 581 83 Linköping, Sweden
| | - Per Jensen
- IFM Biology, AVIAN Behavioural Genomics and Physiology group, Linköping University, 581 83 Linköping, Sweden.
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9
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Hansen Wheat C, Larsson L, Berner P, Temrin H. Commentary by Gácsi et al. (2023) highlights general misconceptions within the field of dog domestication and dog-wolf comparisons. Ecol Evol 2023; 13:e10466. [PMID: 37736276 PMCID: PMC10509154 DOI: 10.1002/ece3.10466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 08/18/2023] [Indexed: 09/23/2023] Open
Affiliation(s)
| | - Linn Larsson
- Department of ZoologyStockholm UniversityStockholmSweden
| | | | - Hans Temrin
- Department of ZoologyStockholm UniversityStockholmSweden
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10
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Sexton CL, Buckley C, Lieberfarb J, Subiaul F, Hecht EE, Bradley BJ. What Is Written on a Dog's Face? Evaluating the Impact of Facial Phenotypes on Communication between Humans and Canines. Animals (Basel) 2023; 13:2385. [PMID: 37508162 PMCID: PMC10376741 DOI: 10.3390/ani13142385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 07/15/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
Facial phenotypes are significant in communication with conspecifics among social primates. Less is understood about the impact of such markers in heterospecific encounters. Through behavioral and physical phenotype analyses of domesticated dogs living in human households, this study aims to evaluate the potential impact of superficial facial markings on dogs' production of human-directed facial expressions. That is, this study explores how facial markings, such as eyebrows, patches, and widow's peaks, are related to expressivity toward humans. We used the Dog Facial Action Coding System (DogFACS) as an objective measure of expressivity, and we developed an original schematic for a standardized coding of facial patterns and coloration on a sample of more than 100 male and female dogs (N = 103), aged from 6 months to 12 years, representing eight breed groups. The present study found a statistically significant, though weak, correlation between expression rate and facial complexity, with dogs with plainer faces tending to be more expressive (r = -0.326, p ≤ 0.001). Interestingly, for adult dogs, human companions characterized dogs' rates of facial expressivity with more accuracy for dogs with plainer faces. Especially relevant to interspecies communication and cooperation, within-subject analyses revealed that dogs' muscle movements were distributed more evenly across their facial regions in a highly social test condition compared to conditions in which they received ambiguous cues from their owners. On the whole, this study provides an original evaluation of how facial features may impact communication in human-dog interactions.
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Affiliation(s)
- Courtney L Sexton
- Department of Population Health Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052, USA
| | - Colleen Buckley
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052, USA
| | | | - Francys Subiaul
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052, USA
- Department of Speech, Language and Hearing Sciences, The George Washington University, Washington, DC 20052, USA
| | - Erin E Hecht
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Brenda J Bradley
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052, USA
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11
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Boch M, Wagner IC, Karl S, Huber L, Lamm C. Functionally analogous body- and animacy-responsive areas are present in the dog (Canis familiaris) and human occipito-temporal lobe. Commun Biol 2023; 6:645. [PMID: 37369804 PMCID: PMC10300132 DOI: 10.1038/s42003-023-05014-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Comparing the neural correlates of socio-cognitive skills across species provides insights into the evolution of the social brain and has revealed face- and body-sensitive regions in the primate temporal lobe. Although from a different lineage, dogs share convergent visuo-cognitive skills with humans and a temporal lobe which evolved independently in carnivorans. We investigated the neural correlates of face and body perception in dogs (N = 15) and humans (N = 40) using functional MRI. Combining univariate and multivariate analysis approaches, we found functionally analogous occipito-temporal regions involved in the perception of animate entities and bodies in both species and face-sensitive regions in humans. Though unpredicted, we also observed neural representations of faces compared to inanimate objects, and dog compared to human bodies in dog olfactory regions. These findings shed light on the evolutionary foundations of human and dog social cognition and the predominant role of the temporal lobe.
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Affiliation(s)
- Magdalena Boch
- Social, Cognitive and Affective Neuroscience Unit, Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria.
- Department of Cognitive Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria.
| | - Isabella C Wagner
- Social, Cognitive and Affective Neuroscience Unit, Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria
- Vienna Cognitive Science Hub, University of Vienna, Vienna, Austria
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Sabrina Karl
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Vienna, Austria
| | - Ludwig Huber
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Vienna, Austria
| | - Claus Lamm
- Social, Cognitive and Affective Neuroscience Unit, Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria
- Vienna Cognitive Science Hub, University of Vienna, Vienna, Austria
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12
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Salomons H, Smith KCM, Callahan-Beckel M, Callahan M, Levy K, Kennedy BS, Bray EE, Gnanadesikan GE, Horschler DJ, Gruen M, Tan J, White P, vonHoldt BM, MacLean EL, Hare B. Response to Hansen Wheat et al.: Additional analysis further supports the early emergence of cooperative communication in dogs compared to wolves raised with more human exposure. Learn Behav 2023; 51:131-134. [PMID: 36810744 DOI: 10.3758/s13420-023-00576-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2023] [Indexed: 02/23/2023]
Abstract
Here, we address Hansen Wheat et al.'s commentary in this journal in response to Salomons et al. Current Biology, 31(14), 3137-3144.E11, (2021). We conduct additional analyses in response to Hansen Wheat et al.'s two main questions. First, we examine the claim that it was the move to a human home environment which enabled the dog puppies to outperform the wolf puppies in gesture comprehension tasks. We show that the youngest dog puppies who had not yet been individually placed in raisers' homes were still highly skilled, and outperformed similar-aged wolf puppies who had higher levels of human interaction. Second, we address the claim that willingness to approach a stranger can explain the difference between dog and wolf pups' ability to succeed in gesture comprehension tasks. We explain the various controls in the original study that render this explanation insufficient, and demonstrate via model comparison that the covariance of species and temperament also make this parsing impossible. Overall, our additional analyses and considerations support the domestication hypothesis as laid out by Salomons et al. Current Biology, 31(14), 3137-3144.E11, (2021).
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Affiliation(s)
- Hannah Salomons
- Department of Evolutionary Anthropology, Duke University, Durham, NC, 27708, USA.
| | - Kyle C M Smith
- Department of Anthropology, Pennsylvania State University, State College, PA, 16801, USA
| | | | | | - Kerinne Levy
- Canine Companions for Independence, Santa Rosa, CA, 95407, USA
| | | | - Emily E Bray
- Canine Companions for Independence, Santa Rosa, CA, 95407, USA
- School of Anthropology, University of Arizona, Tucson, AZ, 85721, USA
| | - Gitanjali E Gnanadesikan
- School of Anthropology, University of Arizona, Tucson, AZ, 85721, USA
- Cognitive Science Program, University of Arizona, Tucson, AZ, 85721, USA
| | - Daniel J Horschler
- School of Anthropology, University of Arizona, Tucson, AZ, 85721, USA
- Cognitive Science Program, University of Arizona, Tucson, AZ, 85721, USA
| | - Margaret Gruen
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, USA
| | - Jingzhi Tan
- Department of Psychology, Leiden University, 2311, EZ, Leiden, the Netherlands
| | - Philip White
- Department of Statistics, Brigham Young University, Provo, UT, 84602, USA
| | - Bridgett M vonHoldt
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Evan L MacLean
- College of Veterinary Medicine, University of Arizona, Tucson, AZ, 85721, USA
- Department of Psychology, University of Arizona, Tucson, AZ, 85721, USA
| | - Brian Hare
- Department of Evolutionary Anthropology, Duke University, Durham, NC, 27708, USA
- Center for Cognitive Neuroscience, Duke University, Durham, NC, 27708, USA
- Psychology and Neuroscience, Duke University, Durham, NC, 27708, USA
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13
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Hansen Wheat C, van der Bijl W, Wynne CDL. Rearing condition and willingness to approach a stranger explain differences in point following performance in wolves and dogs. Learn Behav 2023; 51:127-130. [PMID: 36224508 DOI: 10.3758/s13420-022-00544-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2022] [Indexed: 11/05/2022]
Abstract
The relative importance of adaptation and individual ontogenetic experience in dogs' high levels of behavioral compatibility with humans has been a topic of intense scientific attention over the past two decades. Salomons et al. Current Biology, 31, 3137-3144, (2021) recently presented a particularly rich data set of observations on both wolf and dog puppies that has the potential to contribute substantially to this debate. In their study subjecting wolf and dog puppies to batteries of tests, including the ability to follow human pointing gestures, Salomons et al. (2021) reported that dogs, but not wolves, have a specialized innate capacity for cooperation with humans. However, upon reanalyzing this data set, we reach a different conclusion-namely, that when controlling adequately for various environmental factors, wolves and dogs perform similarly in their cooperation with humans.
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Affiliation(s)
| | - Wouter van der Bijl
- Department of Zoology & Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Clive D L Wynne
- Canine Science Collaboratory, Department of Psychology, Arizona State University, Tempe, AZ, USA
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14
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Davis KM, Partin AM, Burghardt GM, Springer CM, Albright JD. A Descriptive Methodology for Studying the Ontogeny of Object Play and Breed Differences in Dogs ( Canis lupus familiaris). Animals (Basel) 2023; 13:ani13081371. [PMID: 37106934 PMCID: PMC10135149 DOI: 10.3390/ani13081371] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/29/2023] Open
Abstract
Play behavior is a prominent aspect of juvenile behavior for many animals, yet early development, especially play with objects, has received little attention. Our previous study on object play introduced our general methods, focusing on litter differences in the developmental trajectory of object play and toy preferences. Here, we present a detailed ethogram of more than 30 observed object play behaviors. We focus on breed differences in the development of play in the three following breeds: Welsh Terriers, Vizslas, and standard Poodles. Puppies were video recorded from 3 to 7 weeks of age at half-week intervals upon the introduction of a standard set of five toys into their home environments. Ten minutes of video from each session for each puppy were analyzed using the Noldus Observer XT program. Aside from analyzing individual behaviors, they were also grouped into three behavioral categories. These were behaviors that occurred only in a solitary context, only in a social context, or in both contexts. Solitary object play developed first, and social object play developed later across breeds. There was a significant three-way interaction between breed, developmental age, and the context in which play occurred. Pairwise comparisons within each breed, age, and context are discussed, but a prominent result is that the onset of many behaviors occurred later in Welsh Terriers compared to the other breeds.
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Affiliation(s)
- Karen M Davis
- Department of Psychology, SUNY Potsdam, Potsdam, NY 13676, USA
- Department of Psychology, University of Tennessee, Knoxville, TN 37996, USA
- Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Adam M Partin
- Department of Psychology, University of Tennessee, Knoxville, TN 37996, USA
| | - Gordon M Burghardt
- Department of Psychology, University of Tennessee, Knoxville, TN 37996, USA
- Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Cary M Springer
- Office of Information Technology, Research Computing Support, University of Tennessee, Knoxville, TN 37996, USA
| | - Julia D Albright
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA
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15
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Byrne M, Horschler DJ, Schmitt M, Johnston AM. Pet dogs (Canis familiaris) re-engage humans after joint activity. Anim Cogn 2023:10.1007/s10071-023-01774-1. [PMID: 37052862 DOI: 10.1007/s10071-023-01774-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/14/2023]
Abstract
Joint intentionality, the mutual understanding of shared goals or actions to partake in a common task, is considered an essential building block of theory of mind in humans. Domesticated dogs are unusually adept at comprehending human social cues and cooperating with humans, making it possible that they possess behavioral signatures of joint intentionality in interactions with humans. Horschler and colleagues (Anim Behav 183: 159-168, 2022) examined joint intentionality in a service dog population, finding that upon interruption of a joint experience, dogs preferentially re-engaged their former partner over a passive bystander, a behavior argued to be a signature of joint intentionality in human children. In the current study, we aimed to replicate and extend these results in pet dogs. One familiar person played with the dog and then abruptly stopped. We examined if dogs would preferentially re-engage the player instead of a familiar bystander who was also present. Consistent with the findings of Horschler and colleagues (Anim Behav 183: 159-168, 2022), pet dogs preferentially gazed toward and offered the toy to the player significantly more than the familiar bystander. However, no difference was observed in physical contact. These findings provide preliminary evidence for behavioral signatures of joint intentionality in pet dogs, but future work is needed to understand whether this phenomenon extends to other contexts.
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Affiliation(s)
- Molly Byrne
- Department of Psychology, Boston College, 140 Commonwealth Ave., Chestnut Hill, MA, 02467, USA.
| | - Daniel J Horschler
- Department of Psychology, Yale University, 2 Hillhouse Ave, New Haven, CT, 06511, USA
| | - Mark Schmitt
- Department of Psychology, Boston College, 140 Commonwealth Ave., Chestnut Hill, MA, 02467, USA
| | - Angie M Johnston
- Department of Psychology, Boston College, 140 Commonwealth Ave., Chestnut Hill, MA, 02467, USA
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16
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Following the human point: Research with nonhuman animals since Povinelli, Nelson, and Boysen (1990). Learn Behav 2023; 51:34-47. [PMID: 36175744 DOI: 10.3758/s13420-022-00546-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2022] [Indexed: 11/08/2022]
Abstract
For this special issue in honor of Dr. Sarah (Sally) Boysen's career, we review studies on point following in nonhuman animals. Of the 126 papers that we documented on this topic published since the publication of Povinelli, Nelson, and Boysen (1990, Journal of Comparative Psychology, 104, 203-210), 94 (75%) were published in the past 15 years, including 22 in the past 5 years, indicating that this topic is still an active area of interest in the field of animal behavior and cognition. We present results of a survey of publication trends, discussing the species tested and the sample sizes, and we note methodological considerations and current multilaboratory approaches. We then categorize and synthesize the research questions addressed in these studies, which have been at both the ultimate level (e.g., questions related to evolutionary adaptiveness and phylogenetic differences) and proximate level (e.g., questions related to experiential and temperamental processes). Throughout, we consider future directions for this area of research.
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17
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Abstract
An important question in the study of canine cognition is how dogs understand humans, given that they show impressive abilities for interacting and communicating with us. In this review, we describe and discuss studies that have investigated dogs' perspective-taking abilities. There is solid evidence that dogs are not only sensitive to the gaze of others, but also their attention. We specifically address the question whether dogs have the ability to take the perspective of others and thus come to understand what others can or cannot perceive. From the latter, they may then infer what others know and use this representation to anticipate what others do next. Still, dogs might simply rely on directly observable cues and on what they themselves can perceive when they assess what others can perceive. And instead of making inferences from representations of others' mental states, they may have just learned that certain behaviours of ours lead to certain outcomes. However, recent research seems to challenge this low-level explanation. Dogs have solved several perspective-taking tasks instantly and reliably across a large number of variations, including geometrical gaze-following, stealing in the dark, concealing information from others, and Guesser/Knower differentiation. In the latter studies, dogs' choices between two human informants were strongly influenced by cues related to the humans' visual access to the food, even when the two informants behaved identically. And finally, we review a recent study that found dogs reacting differently to misleading suggestions of human informants that have either a true or false belief about the location of food. We discuss this surprising result in terms of the comprehension of reality-incongruent mental states, which is considered as a hallmark of Theory of Mind acquisition in human development. Especially on the basis of the latter findings, we conclude that pet dogs might be sensitive to what others see, know, intend, and believe. Therefore, this ability seems to have evolved not just in the corvid and primate lineages, but also in dogs.
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Affiliation(s)
- Ludwig Huber
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Veterinaerplatz 1, 1210, Vienna, Austria.
| | - Lucrezia Lonardo
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
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Comparing wolves and dogs: current status and implications for human ‘self-domestication’. Trends Cogn Sci 2022; 26:337-349. [DOI: 10.1016/j.tics.2022.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 01/02/2023]
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Horschler DJ, Bray EE, Gnanadesikan GE, Byrne M, Levy KM, Kennedy BS, MacLean EL. Dogs re-engage human partners when joint social play is interrupted: a behavioural signature of shared intentionality? Anim Behav 2022. [DOI: 10.1016/j.anbehav.2021.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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20
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Adjustment in the point-following behaviour of free-ranging dogs - roles of social petting and informative-deceptive nature of cues. Anim Cogn 2021; 25:571-579. [PMID: 34743236 DOI: 10.1007/s10071-021-01573-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/06/2021] [Accepted: 10/21/2021] [Indexed: 10/19/2022]
Abstract
Animals of different taxa can read and respond to various human communicative signals. Such a mechanism facilitates animals to acquire social information and helps them react in a context-dependent manner. Dogs have garnered extensive attention owing to their socio-cognitive skills and remarkable sensitivity to human social cues. For example, dogs readily respond to different human pointing gestures to locate hidden food rewards. However, a general inclination towards testing highly socialized pet dogs has resulted in a dearth of information on other sub-populations of dogs. Free-ranging dogs are one of the least socialized dog populations yet exhibit point-following behaviour flexibly. As a consequence of frequent negative interspecific interactions, they are typically wary of unfamiliar humans; thus, contextual recognition of human actions is paramount for these dogs to avoid potential conflict. However, the mechanisms influencing their point-following behaviour remain unidentified. We asked to what extent the informative-deceptive nature of cues and positive human interactions influence the interspecific communicative behaviour of these minimally socialized dogs. Using a point-following experiment with a 2 × 2 design, we focused on adult free-ranging dogs' behavioural adjustments. Dogs were randomly divided into two groups, with only one receiving brief social petting. Further, informative and deceptive cues were given to separate subsets within each group. Our findings suggest that brief social petting strongly affects the likelihood of free-ranging dogs' point-following tendencies. Dogs who received petting followed the pointing cues regardless of their informative or deceptive nature, whereas dogs who did not receive petting discriminated between informative and deceptive pointing. This study highlights the contribution of positive human interaction and informative-deceptive quality of cues in modulating the behavioural responses of free-ranging dogs in an interspecific communicative context.
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Benítez-Burraco A, Pörtl D, Jung C. Did Dog Domestication Contribute to Language Evolution? Front Psychol 2021; 12:695116. [PMID: 34589022 PMCID: PMC8473740 DOI: 10.3389/fpsyg.2021.695116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/02/2021] [Indexed: 11/20/2022] Open
Abstract
Different factors seemingly account for the emergence of present-day languages in our species. Human self-domestication has been recently invoked as one important force favoring language complexity mostly via a cultural mechanism. Because our self-domestication ultimately resulted from selection for less aggressive behavior and increased prosocial behavior, any evolutionary or cultural change impacting on aggression levels is expected to have fostered this process. Here, we hypothesize about a parallel domestication of humans and dogs, and more specifically, about a positive effect of our interaction with dogs on human self-domestication, and ultimately, on aspects of language evolution, through the mechanisms involved in the control of aggression. We review evidence of diverse sort (ethological mostly, but also archeological, genetic, and physiological) supporting such an effect and propose some ways of testing our hypothesis.
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Affiliation(s)
- Antonio Benítez-Burraco
- Department of Spanish, Linguistics, and Theory of Literature (Linguistics), Faculty of Philology, University of Seville, Seville, Spain
| | - Daniela Pörtl
- Psychiatric Department, Saale-Unstrut Klinikum, Teaching Hospital Leipzig and Jena Universities, Naumburg, Germany
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Abstract
Domestic dogs show socio-cognitive abilities that are not found in other species, including dogs' closest living relative, the wolf. From early on dogs are good at reading human gestures and pay attention to humans' eyes and voice. Two new studies suggest that a heritable component to dogs' social cognitive skills exists and that selection during domestication must have played a role in enhancing dogs' social cognitive skills.
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