Morphological variants of silent bared-teeth displays have different social interaction outcomes in crested macaques (Macaca nigra).
Am J Phys Anthropol
; 173(3): 411-422, 2020 11.
Article
in En
| MEDLINE
| ID: mdl-32820559
ABSTRACT
OBJECTIVES:
While it has been demonstrated that even subtle variation in human facial expressions can lead to significant changes in the meaning and function of expressions, relatively few studies have examined primate facial expressions using similarly objective and rigorous analysis. Construction of primate facial expression repertoires may, therefore, be oversimplified, with expressions often arbitrarily pooled and/or split into subjective pigeonholes. Our objective is to assess whether subtle variation in primate facial expressions is linked to variation in function, and hence to inform future attempts to quantify complexity of facial communication. MATERIALS ANDMETHODS:
We used Macaque Facial Action Coding System, an anatomically based and hence more objective tool, to quantify "silent bared-teeth" (SBT) expressions produced by wild crested macaques engaging in spontaneous behavior, and utilized discriminant analysis and bootstrapping analysis to look for morphological differences between SBT produced in four different contexts, defined by the outcome of interactions Affiliation, Copulation, Play, and Submission.RESULTS:
We found that SBT produced in these contexts could be distinguished at significantly above-chance rates, indicating that the expressions produced in these four contexts differ morphologically. We identified the specific facial movements that were typically used in each context, and found that the variability and intensity of facial movements also varied between contexts.DISCUSSION:
These results indicate that nonhuman primate facial expressions share the human characteristic of exhibiting meaningful subtle differences. Complexity of facial communication may not be accurately represented simply by building repertoires of distinct expressions, so further work should attempt to take this subtle variability into account.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Social Behavior
/
Facial Expression
/
Macaca
Type of study:
Prognostic_studies
Aspects:
Determinantes_sociais_saude
Limits:
Animals
Language:
En
Journal:
Am J Phys Anthropol
Year:
2020
Document type:
Article
Affiliation country:
United kingdom