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Adult but not juvenile Barbary macaques spontaneously recognize group members from pictures.

Schell A, Rieck K, Schell K, Hammerschmidt K, Fischer J - Anim Cogn (2011)

Bottom Line: This ability appears to develop with age, as juveniles did not discriminate between members of their own group and another group, although they showed generally more interest in the pictures than did adults.Whether the difference in behaviour is based on individual recognition of one's own group members or simply the discrimination based on familiarity remains unresolved.However, both mechanisms would be sufficient for group membership identification.

View Article: PubMed Central - PubMed

Affiliation: Cognitive Ethology Lab, German Primate Center, Göttingen, Germany.

ABSTRACT
For group-living animals, it is crucial to distinguish one's own group members from those of other groups. Studies applying operant conditioning revealed that monkeys living in relatively small groups are able to recognize their own group members when tested with photographs of group members and other conspecifics. Employing a simple looking time paradigm, we here show that Barbary macaques living in two social groups comprising 46 and 57 individuals, respectively, at the enclosure 'La Forêt des Singes' at Rocamadour are able to spontaneously distinguish photographs of members of their own group from those depicting animals that belong to another group. This ability appears to develop with age, as juveniles did not discriminate between members of their own group and another group, although they showed generally more interest in the pictures than did adults. Juveniles frequently displayed picture directed behaviours such as lip-smacking, touching and sniffing in both conditions, indicating that the stimuli were highly salient to them. In conclusion, it appears that at least adult monkeys are able to memorize the faces of a large number of individuals. Whether the difference in behaviour is based on individual recognition of one's own group members or simply the discrimination based on familiarity remains unresolved. However, both mechanisms would be sufficient for group membership identification.

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Mean (±SEM) total looking time of juveniles and adults to portraits of group members and nongroup members
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Fig3: Mean (±SEM) total looking time of juveniles and adults to portraits of group members and nongroup members

Mentions: Subjects looked significantly longer at pictures of faces than at the empty sheet of paper (facial stimuli X ± SEM 6.9 ± 0.7 s (N = 177) compared to 1.3 ± 0.3 s for control stimuli (N = 20); F1,194.1 = 7.2; P = 0.008). Juveniles did not show differential responses to pictures of their own and another group’s members (‘own group’: 11.0 ± 2.3 s; N = 33, ‘other group’: 10.6 ± 1.4 s; N = 32; F1,61.1 = 0.66; P = 0.798; Fig. 3). In contrast, adult Barbary macaques spent significantly more time looking at pictures of other group members (5.9 s ± 1.1; N = 58) than at pictures from their own group members (3.3 s ± 0.5; N = 54); F1,106.5 = 5.09; P = 0.026, Fig. 3). Across categories, juvenile Barbary macaques showed significantly longer responses than adults (juveniles: 10.8 ± 1.4 s, adults: 4.6 ± 0.6 s; F1,99.9 = 20.37; P < 0.000; Fig. 3).Fig. 3


Adult but not juvenile Barbary macaques spontaneously recognize group members from pictures.

Schell A, Rieck K, Schell K, Hammerschmidt K, Fischer J - Anim Cogn (2011)

Mean (±SEM) total looking time of juveniles and adults to portraits of group members and nongroup members
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3117280&req=5

Fig3: Mean (±SEM) total looking time of juveniles and adults to portraits of group members and nongroup members
Mentions: Subjects looked significantly longer at pictures of faces than at the empty sheet of paper (facial stimuli X ± SEM 6.9 ± 0.7 s (N = 177) compared to 1.3 ± 0.3 s for control stimuli (N = 20); F1,194.1 = 7.2; P = 0.008). Juveniles did not show differential responses to pictures of their own and another group’s members (‘own group’: 11.0 ± 2.3 s; N = 33, ‘other group’: 10.6 ± 1.4 s; N = 32; F1,61.1 = 0.66; P = 0.798; Fig. 3). In contrast, adult Barbary macaques spent significantly more time looking at pictures of other group members (5.9 s ± 1.1; N = 58) than at pictures from their own group members (3.3 s ± 0.5; N = 54); F1,106.5 = 5.09; P = 0.026, Fig. 3). Across categories, juvenile Barbary macaques showed significantly longer responses than adults (juveniles: 10.8 ± 1.4 s, adults: 4.6 ± 0.6 s; F1,99.9 = 20.37; P < 0.000; Fig. 3).Fig. 3

Bottom Line: This ability appears to develop with age, as juveniles did not discriminate between members of their own group and another group, although they showed generally more interest in the pictures than did adults.Whether the difference in behaviour is based on individual recognition of one's own group members or simply the discrimination based on familiarity remains unresolved.However, both mechanisms would be sufficient for group membership identification.

View Article: PubMed Central - PubMed

Affiliation: Cognitive Ethology Lab, German Primate Center, Göttingen, Germany.

ABSTRACT
For group-living animals, it is crucial to distinguish one's own group members from those of other groups. Studies applying operant conditioning revealed that monkeys living in relatively small groups are able to recognize their own group members when tested with photographs of group members and other conspecifics. Employing a simple looking time paradigm, we here show that Barbary macaques living in two social groups comprising 46 and 57 individuals, respectively, at the enclosure 'La Forêt des Singes' at Rocamadour are able to spontaneously distinguish photographs of members of their own group from those depicting animals that belong to another group. This ability appears to develop with age, as juveniles did not discriminate between members of their own group and another group, although they showed generally more interest in the pictures than did adults. Juveniles frequently displayed picture directed behaviours such as lip-smacking, touching and sniffing in both conditions, indicating that the stimuli were highly salient to them. In conclusion, it appears that at least adult monkeys are able to memorize the faces of a large number of individuals. Whether the difference in behaviour is based on individual recognition of one's own group members or simply the discrimination based on familiarity remains unresolved. However, both mechanisms would be sufficient for group membership identification.

Show MeSH
Related in: MedlinePlus