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Journal of Comparative Psychology - Vol 131, Iss 3

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Journal of Comparative Psychology The Journal of Comparative Psychology publishes original empirical and theoretical research from a comparative perspective on the behavior, cognition, perception, and social relationships of diverse species.
Copyright 2017 American Psychological Association
  • Yawning and social styles: Different functions in tolerant and despotic macaques (Macaca tonkeana and Macaca fuscata).
    Yawning is a multifunctional behavior with a role in social communication. In Old World monkeys, the “tension yawn” is often used as a threat, allowing individuals to completely expose their canines. To explore the role of this phenomenon, we selected 2 closely related species—Japanese macaques (Macaca fuscata) and Tonkean macaques (M. tonkeana)—which differ primarily in terms of their tolerance levels. Japanese macaques are classified as despotic; Tonkean macaques are classified as tolerant. Both species live in multimale–multifemale societies, show a high level of sexual dimorphism, and have comparable yawning repertoires that include displaying a covered teeth yawn and an uncovered gums yawn. We found comparable baseline frequencies of the 2 yawning types and a similar distribution of these behaviors according to sex (males yawned more frequently than females). This morphological homogeneity permitted us to evaluate potential differences in the meaning of yawning as a function of social tension, aggressive contexts, and dominance hierarchy. Divergent social styles determine a functional dichotomy in the use of the covered teeth yawn and the uncovered gums yawn. The covered teeth yawn is not susceptible to social and environmental stimuli and seems to be a form of yawning mostly linked to the physiology of the sleep–wake cycle. However, the uncovered gums yawn is modulated according to different social contexts, and its use could be favored by natural selection, especially in tolerant species, which apparently require more elaborate forms of social communication. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Adaptation of the Arizona Cognitive Task Battery for use with the Ts65Dn mouse model (Mus musculus) of Down syndrome.
    We propose and validate a clear strategy to efficiently and comprehensively characterize neurobehavioral deficits in the Ts65Dn mouse model of Down syndrome. This novel approach uses neurocognitive theory to design and select behavioral tasks that test specific hypotheses concerning the results of Down syndrome. In this article, we model the Arizona Cognitive Task Battery, used to study human populations with Down syndrome, in Ts65Dn mice. We observed specific deficits for spatial memory, impaired long-term memory for visual objects, acquisition and reversal of motor responses, reduced motor dexterity, and impaired adaptive function as measured by nesting and anxiety tasks. The Ts65Dn mice showed intact temporal ordering, novelty detection, and visual object recognition with short delays. These results phenocopy the performance of participants with Down syndrome on the Arizona Cognitive Task Battery. This approach extends the utility of mouse models of Down syndrome by integrating the expertise of clinical neurology and cognitive neuroscience into the mouse behavioral laboratory. Further, by directly emphasizing the reciprocal translation of research between human disease states and the associated mouse models, we demonstrate that it is possible for both groups to mutually inform each other’s research to more efficiently generate hypotheses and elucidate treatment strategies. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Female bearded capuchin monkeys (Sapajus libidinosus) use objects to solicit the sexual partner.
    Female wild bearded capuchins (Sapajus libidinosus) living at Serra da Capivara National Park (SCNP) that use stone and stick tools during foraging occasionally toss or throw stones at the male during courtship. We report similar behaviors in a different population that uses stones as tools in foraging. We video-recorded the sexual behavior of four females (27 days during nine proceptive periods) belonging to a group of wild capuchins living in Fazenda Boa Vista (FBV), 320 km from SCNP. Three females used stones or branches when they solicited the alpha male (79 episodes). The female that did not use objects was the sole female to solicit a subordinate male. The vast majority of episodes (95%) involved pushing or dropping branches, both loose and attached to the tree, toward the male. Females used objects only during the one-way courtship phase, before the male reciprocated the female’s solicitations. In 93% of the episodes in which a female used objects, she performed affiliative behaviors immediately before or after using the objects. We conclude that throwing or pounding stones and pushing or dropping branches by females in SCNP and FBV in the sexual context have a clear affiliative meaning (to attract the male’s attention). Given the tool-using status of both populations where these behaviors have been reported, it is important to determine whether they appear in populations that do not use tools, or are restricted to populations already primed to use objects in other contexts. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Schedule of human-controlled periods structures bottlenose dolphin (Tursiops truncatus) behavior in their free-time.
    Behavioral patterns are established in response to predictable environmental cues. Animals under human care frequently experience predictable, human-controlled events each day, but very few studies have questioned exactly how behavioral patterns are affected by such activities. Bottlenose dolphins (Tursiops truncatus) maintained for public display are good models to study such patterns since they experience multiple daily human-controlled periods (e.g., shows, training for shows, medical training). Thus, we investigated the effect of training session schedule on their “free-time” behavior, studying 29 individuals within 4 groups from 3 European facilities. Our initial time budget analyses revealed that among the behaviors studied, dolphins spent the most time engaged in synchronous swimming, and within this category swam most at slow speeds and in close proximity to each other. “Slow-close” synchronous swimming peaked shortly after training sessions and was low shortly before the next session. Play behavior had significantly higher frequencies in juveniles than in adults, but the effect was only seen during the in-between session period (interval neither shortly before nor after sessions). Anticipatory behavior toward sessions was significantly higher shortly before sessions and lower afterward. We conclude that dolphin behaviors unconnected to the human-controlled periods were modulated by them: slow-close synchronous swimming and age-dependent play, which have important social dimensions and links to welfare. We discuss potential parallels to human-controlled periods in other species, including humans themselves. Our findings could be taken into account when designing welfare assessments, and aid in the provision of enrichment and maintaining effective schedules beneficial to animals themselves. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Early expression of manual lateralization in bipedal marsupials.
    Robust lateralization in forelimb use has recently been found in bipedal, but not quadrupedal, marsupial mammals. The link between bipedality and handedness, occurring in both marsupials and primates, remains to be investigated. To shed light on the developmental origins of marsupial manual lateralization, infants of macropod marsupials were examined before and shortly after the acquisition of habitual bipedal posture and locomotion. Forelimb preferences were assessed in natural, not artificially evoked, behaviors of infant red-necked wallaby in the wild and infant eastern gray kangaroo in free-ranging captivity. Pouch young of both species showed population-level left-forelimb preference when manipulating food objects, such as leaves and grass blades. This result provides the first report of lateralization in pouch young marsupials and rare evidence of lateralized manual activity in early mammalian ontogenesis. Young-at-foot juveniles of eastern gray kangaroo preferred to use the left forelimb to manipulate the mother’s pouch edge as previously shown for red-necked wallaby. In both species, the direction of biases in manipulative behavior for young-at-foot and pouch young was the same as in adults. Forelimb preferences in offspring were positively correlated with the forelimb preferences of their mothers. Our results strongly suggest that the emergence of individual and population-level forelimb preferences in macropod infants precedes the onset of independent standing and locomotion. In all probability, manual lateralization in bipedal marsupials, such as kangaroos and wallabies, is not determined by the acquisition of habitual bipedality in the course of ontogenesis. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Transitive inference in humans (Homo sapiens) and rhesus macaques (Macaca mulatta) after massed training of the last two list items.
    Transitive inference (TI) is a classic learning paradigm for which the relative contributions of experienced rewards and representation-based inference have been debated vigorously, particularly regarding the notion that animals are capable of logic and reasoning. Rhesus macaque subjects and human participants performed a TI task in which, prior to learning a 7-item list (ABCDEFG), a block of trials presented exclusively the pair FG. Contrary to the expectation of associative models, the high prior rate of reward for F did not disrupt subsequent learning of the entire list. Monkeys (who each completed many sessions with novel stimuli) learned to anticipate that novel stimuli should be preferred over F. We interpret this as evidence of a task representation of TI that generalizes beyond learning about specific stimuli. Humans (who were task-naïve) showed a transitory bias to F when it was paired with novel stimuli, but very rapidly unlearned that bias. Performance with respect to the remaining stimuli was consistent with past reports of TI in both species. These results are difficult to reconcile with any account that assigns the strength of association between individual stimuli and rewards. Instead, they support sophisticated cognitive processes in both species, albeit with some species differences. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Association between lateral bias and personality traits in the domestic dog (Canis familiaris).
    Behavioral laterality reflects the cerebral functional asymmetry. Measures of laterality have been associated with emotional stress, problem-solving, and personality in some vertebrate species. Thus far, the association between laterality and personality in the domestic dog has been largely overlooked. In this study, we investigated whether lateralized (left or right) and ambilateral dogs differed in their behavioral response to a standardized personality test. The dog’s preferred paw to hold a Kong ball filled with food and the first paw used to step-off from a standing position were scored as laterality measures. The Dog Mentality Assessment (DMA) test was used to assess 5 personality traits (e.g., sociability, aggressiveness) and a broader shy-boldness dimension. No differences emerged between left- and right-biased dogs on any personality trait. Instead, ambilateral dogs, scored using the Kong test, scored higher on their playfulness (Z = −1.98, p = .048) and Aggressiveness (Z = −2.10, p = .036) trait scores than did lateralized (irrespective of side) dogs. Also, ambilateral dogs assessed by using the First-Stepping test scored higher than lateralized dogs on the Sociability (Z = −2.83, p = .005) and Shy-Boldness (Z = −2.34, p = .019) trait scores. Overall, we found evidence of a link between canine personality and behavioral laterality, and this was especially true for those traits relating to stronger emotional reactivity, such as aggressiveness, fearfulness, and sociability. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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  • Do tiger keelback snakes (Rhabdophis tigrinus) recognize how toxic they are?
    Animals that depend on defensive chemicals acquired from food may face a decision when attempting to deter predatory attacks: Should they exhibit antipredator behavior that relies on the toxicity of the sequestered chemicals or should they adopt other behaviors that can avoid predation without using the chemical defense, such as flight? Thus, it is reasonable to assume that animals that sequester prey toxins have evolved the ability to flexibly change their antipredator responses according to the amount of toxin-resource they have consumed. We tested this hypothesis using an Asian snake, Rhabdophis tigrinus, that sequesters toxins from toads consumed as food and stores them in specialized organs back of the head, called nuchal glands. We reared hatchling snakes from toad-free and toad-rich islands on controlled diets and examined their subsequent antipredator responses after 3 and 6 month feeding. Juveniles from a toad-free island that had been fed a diet including toads for 3 months showed antipredator displays associated with the nuchal glands more frequently than those that had been fed a diet without toads. They showed a similar, but less clear, tendency after 6 months feeding. Juveniles from the toad-rich island did not show a clear tendency of dietary effect. We discuss possible reasons for the different dietary effects between the 2 populations and between the ages. Our results, along with previous related phenomena in other animals, suggest that the ability of self-toxicity-recognition may be widespread in animals that sequester defensive toxins from facultative food. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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