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- Madsen, Elainie, et al.
(författare)
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Chimpanzees show a developmental increase in susceptibility to contagious yawning: A test of the effect of ontogeny and emotional closeness on yawn contagion
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- Contagious yawning has been reported for humans, dogs and several non-human primate species, and associated with empathy in humans and other primates. Still, the function, development and underlying mechanisms of contagious yawning remain unclear. Humans and dogs show a developmental increase in susceptibility to yawn contagion, with children showing an increase around the age of four, when also empathy-related behaviours and accurate identification of others’ emotions begin to clearly evince. Explicit tests of yawn contagion in non-human apes have only involved adult individuals and examined the existence of conspecific yawn contagion. Here we report the first study of heterospecific contagious yawning in primates, and the ontogeny of susceptibility thereto in chimpanzees, Pan troglodytes verus. We examined whether emotional closeness, defined as attachment history with the yawning model, affected the strength of contagion, and compared the contagiousness of yawning to nose-wiping. Thirty-three orphaned chimpanzees observed an unfamiliar and familiar human (their surrogate human mother) yawn, gape and nose-wipe. Yawning, but not nose-wiping, was contagious for juvenile chimpanzees, while infants were immune to contagion. Like humans and dogs, chimpanzees are subject to a developmental trend in susceptibility to contagious yawning, and respond to heterospecific yawn stimuli. Emotional closeness with the model did not affect contagion. The familiarity-biased social modulatory effect on yawn contagion previously found among some adult primates, seem to only emerge later in development, or be limited to interactions with conspecifics. The influence of the ‘chameleon effect’, targeted vs. generalised empathy, perspective-taking and visual attention on contagious yawning is discussed.
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- Madsen, Elainie, et al.
(författare)
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Contagious yawning in domestic dog puppies (Canis lupus familiaris): The effect of ontogeny and emotional closeness on low-level imitation in dogs
- 2013
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Ingår i: Animal Cognition. - : Springer Science and Business Media LLC. - 1435-9456 .- 1435-9448. ; 16:2, s. 233-240
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Tidskriftsartikel (refereegranskat)abstract
- Contagious yawning is a well-documented phenomenon in humans and has recently attracted much attention from developmental and comparative sciences. The function, development and underlying mechanisms of the phenomenon, however, remain largely unclear. Contagious yawning has been demonstrated in dogs and several non-human primate species, and theoretically and empirically associated with empathy in humans and non-human primates. Evidence of emotional closeness modulating contagious yawning in dogs has, nonetheless, been contradictory. Humans show a developmental increase in susceptibility to yawn contagion, with typically developing children displaying a substantial increase at the age of four, when a number of cognitive abilities (e.g. accurate identification of others' emotions) begin to clearly manifest. Explicit tests of yawn contagion in non-human animals have, however, thus far only involved adult individuals. Here, we report a study of the ontogeny of domestic dogs' (Canis lupus familiaris) susceptibility to yawn contagion, and whether emotional closeness to the yawning model affects this. Thirty-five dogs, aged 4-14 months, observed a familiar and unfamiliar human repeatedly yawn or gape. The dogs yawned contagiously, but emotional closeness with the model did not affect the strength of contagion, raising questions as to recent evidence of emotionally modulated auditory contagious yawning in dogs. The dogs showed a developmental effect, with only dogs above 7 months evidencing contagion. The results support the notion of a developmental increase in dogs' attention to others and identification of others' emotional states and suggest that yawn contagion is underpinned by developmental processes shared by humans and other animals.
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- Osvath, Mathias, et al.
(författare)
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Great apes can defer exchange: a replication with different results suggesting future oriented behavior.
- 2013
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Ingår i: Frontiers in Psychology. - : Frontiers Media SA. - 1664-1078. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- The topic of cognitive foresight in non-human animals has received considerable attention in the last decade. The main questions concern whether the animals can prepare for upcoming situations which are, to various degrees, contextually or sensorially detached from the situation in which the preparations are made. Studies on great apes have focused on tool-related tasks, e.g., the ability to select a tool which is functional only in the future. Dufour and Sterck (2008), however, investigated whether chimpanzees were also able to prepare for a future exchange with a human: an object exchanged for a food item. The study included extensive training on the exchangeable item, which is traditionally not compatible with methods for studying planning abilities, as associative learning cannot be precluded. Nevertheless, despite this training, the chimpanzees could not solve the deferred exchange task. Given that great apes can plan for tool use, these results are puzzling. In addition, claims that great ape foresight is highly limited has been based on this study (Suddendorf and Corballis, 2010). Here we partly replicated Dufour and Sterck's study to discern whether temporally deferred and spatially displaced exchange tasks are beyond the capabilities of great apes. In addition to chimpanzees we tested orangutans. One condition followed the one used by Dufour and Sterck, in which the exchange items, functional only in the future, are placed at a location that freely allows for selections by the subjects. In order to test the possibility that the choice set-up could explain the negative results in Dufour and Sterck's study, our second condition followed a method used in the planning study by Osvath and Osvath (2008), where the subjects make a forced one-item-choice from a tray. We found that it is within the capabilities of chimpanzees and orangutans to perform deferred exchange in both conditions.
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