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Author |
Schloegl, C.; Kotrschal, K.; Bugnyar, T. |
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Title |
Modifying the object-choice task: Is the way you look important for ravens? |
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Journal Article |
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Year |
2008 |
Publication |
Behavioural Processes |
Abbreviated Journal |
Behav. Process. |
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77 |
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1 |
Pages |
61-65 |
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Keywords |
Gaze; Modification; Object-choice task; Raven |
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Abstract |
Most animals seem to have difficulties in using gaze cues to find hidden food in object-choice tasks. For instance, chimpanzees usually fail in these tests, even though they are capable of following other's gaze geometrically behind barriers. Similar to chimpanzees, common ravens are skilled in tracking other's gaze but fail in object-choice tasks. We here explored whether procedural modifications, which had been used successfully in chimpanzees, would also yield positive results in ravens. In our modifications (a) the experimenter approached the cup while gazing at it, (b) the gaze cue was accompanied by a sound and (c) the experimenter could actually see the food while giving the gaze cue. Two out of seven birds performed above chance level in some of these conditions. However, we ascribe this improvement to the individuals' learning ability rather than to an understanding of the communicative nature of the task. This interpretation is further supported by results of a follow-up experiment suggesting that ravens may not rely on conspecifics' gaze cues for finding food caches in a natural foraging context. In sum, our results suggest that ravens may not transfer their gaze follow abilities to foraging situations involving hidden food. |
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Equine Behaviour @ team @ |
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4505 |
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Author |
Schmidt, J.; Scheid, C.; Kotrschal, K.; Bugnyar, T.; Schloegl, C. |
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Title |
Gaze direction – A cue for hidden food in rooks (Corvus frugilegus)? |
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Journal Article |
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Year |
2011 |
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Behavioural Processes |
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88 |
Issue |
2 |
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88-93 |
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Keywords |
Gaze; Object choice; Corvids; Effort; Rooks |
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Other individual's head- and eye-directions can be used as social cues indicating the presence of important events. Among birds, ravens and rooks have been shown to co-orient with conspecifics and with humans by following their gaze direction into distant space and behind visual screens. Both species use screens to cache food in private; also, it had been suggested that they may rely on gaze cues to detect hidden food. However, in an object-choice task, ravens failed to do so, and their competitive lifestyle may have prevented them from relying on these cues. Here we tested closely related and cooperative rooks. Food was hidden in one of two cups and the experimenter gazed at the baited cup. In a second experiment, we aimed to increase the birds’ motivation to choose correctly by increasing the investment needed to obtain the reward. To do so, the birds had to pull on a string to obtain the cup. Here, the birds as a group tended to rely on gaze cues. In addition, individual birds quickly learned to use the cue in both experiments. Although rooks may not use gaze cues to find hidden food spontaneously, they may quickly learn to do so. |
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0376-6357 |
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Equine Behaviour @ team @ |
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5420 |
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Fraser, O.N.; Bugnyar, T. |
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Title |
Do Ravens Show Consolation? Responses to Distressed Others |
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Journal Article |
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2010 |
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PLoS ONE |
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PLoS ONE |
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5 |
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5 |
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e10605 |
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<sec> <title>Background</title> <p>Bystander affiliation (post-conflict affiliation from an uninvolved bystander to the conflict victim) may represent an expression of empathy in which the bystander consoles the victim to alleviate the victim's distress (“consolation”). However, alternative hypotheses for the function of bystander affiliation also exist. Determining whether ravens spontaneously offer consolation to distressed partners may not only help us to understand how animals deal with the costs of aggressive conflict, but may also play an important role in the empathy debate.</p> </sec><sec> <title>Methodology/Principal findings</title> <p>This study investigates the post-conflict behavior of ravens, applying the predictive framework for the function of bystander affiliation for the first time in a non-ape species. We found weak evidence for reconciliation (post-conflict affiliation between former opponents), but strong evidence for both bystander affiliation and solicited bystander affiliation (post-conflict affiliation from the victim to a bystander). Bystanders involved in both interactions were likely to share a valuable relationship with the victim. Bystander affiliation offered to the victim was more likely to occur after intense conflicts. Renewed aggression was less likely to occur after the victim solicited affiliation from a bystander.</p> </sec><sec> <title>Conclusions/Significance</title> <p>Our findings suggest that in ravens, bystanders may console victims with whom they share a valuable relationship, thus alleviating the victims' post-conflict distress. Conversely victims may affiliate with bystanders after a conflict in order to reduce the likelihood of renewed aggression. These results stress the importance of relationship quality in determining the occurrence and function of post-conflict interactions, and show that ravens may be sensitive to the emotions of others.</p> </sec> |
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Public Library of Science |
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Equine Behaviour @ team @ |
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5195 |
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Author |
Bugnyar, T.; Stöwe, M.; Heinrich, B. |
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Title |
Ravens, Corvus corax, follow gaze direction of humans around obstacles |
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Journal Article |
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2004 |
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Proceedings of the Royal Society B: Biological Sciences |
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Proc. Roy. Soc. Lond. B Biol. Sci. |
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271 |
Issue |
1546 |
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1331-1336 |
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The ability to follow gaze (i.e. head and eye direction) has recently been shown for social mammals, particularly primates. In most studies, individuals could use gaze direction as a behavioural cue without understanding that the view of others may be different from their own. Here, we show that hand–raised ravens not only visually co–orient with the look–ups of a human experimenter but also reposition themselves to follow the experimenter's gaze around a visual barrier. Birds were capable of visual co–orientation already as fledglings but consistently tracked gaze direction behind obstacles not before six months of age. These results raise the possibility that sub–adult and adult ravens can project a line of sight for the other person into the distance. To what extent ravens may attribute mental significance to the visual behaviour of others is discussed. |
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10.1098/rspb.2004.2738 |
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Call Number |
Equine Behaviour @ team @ |
Serial |
5009 |
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Author |
Bugnyar, T. |
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Title |
Knower–guesser differentiation in ravens: others' viewpoints matter |
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Journal Article |
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Year |
2011 |
Publication |
Proceedings of the Royal Society B: Biological Sciences |
Abbreviated Journal |
Proc. Roy. Soc. Lond. B Biol. Sci. |
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Volume |
278 |
Issue |
1705 |
Pages |
634-640 |
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Differentiating between individuals with different knowledge states is an important step in child development and has been considered as a hallmark in human evolution. Recently, primates and corvids have been reported to pass knower–guesser tasks, raising the possibility of mental attribution skills in non-human animals. Yet, it has been difficult to distinguish ‘mind-reading’ from behaviour-reading alternatives, specifically the use of behavioural cues and/or the application of associatively learned rules. Here, I show that ravens (Corvus corax) observing an experimenter hiding food are capable of predicting the behaviour of bystanders that had been visible at both, none or just one of two caching events. Manipulating the competitors' visual field independently of the view of the test-subject resulted in an instant drop in performance, whereas controls for behavioural cues had no such effect. These findings indicate that ravens not only remember whom they have seen at caching but also take into account that the other's view was blocked. Notably, it does not suffice for the birds to associate specific competitors with specific caches. These results support the idea that certain socio-ecological conditions may select for similar cognitive abilities in distantly related species and that some birds have evolved analogous precursors to a human theory-of-mind. |
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raven; Corvus corax; knowledge attribution; perspective; competitive food retrieval; caching |
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Equine Behaviour @ team @ |
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5287 |
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Author |
Heinrich, B.; Bugnyar, T. |
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Title |
Just how smart are ravens? |
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Journal Article |
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Year |
2007 |
Publication |
Scientific American |
Abbreviated Journal |
Sci Am |
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Volume |
296 |
Issue |
4 |
Pages |
64-71 |
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Keywords |
Animals; *Behavior, Animal; Crows/*physiology; Environment; *Intelligence; Predatory Behavior; Problem Solving; Thinking |
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University of Vermont, USA |
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English |
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0036-8733 |
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PMID:17479632 |
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Equine Behaviour @ team @ |
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4101 |
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