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Simone Schehka presents Poster 73 during the poster sessions in the Aula.
Session theme 6: Free topics
145
Poster 73
ACOUSTICAL EXPRESSION OF AFFECT INTENSITY IN DISTURBANCE
CALLS OF TREE SHREWS
S. Schehka 1 , E. Zimmermann 1
1 Institute for Zoology, University of Veterinary Medicine Hannover, Hannover, Germany
Comparative research on mammal vocalizations may contribute to explore potential universal
coding rules in vocal expressions of specific emotions across species. The goal of this study was to
explore to which extent tree shrews (Tupaia belangeri) convey changing intensities of an affective
state acoustically.
Tree shrews are especially well suited to biomedical stress research, because they display external
signs of the body’s activation in stressfull situations. When confronted with new stimuli of the
environment, they utter disturbance calls, named chatter. In the present study, we used a disturbance
paradigm to evoke chatter calls in captive tree shrews. Subjects (n=10) were removed from their
respective home cage and placed in a new environment for the duration of 30 min.
To determine the intensity of the affective state of an animal, we looked for a behavioral indicator
of arousal in tree shrews, the tail position. The frame-by-frame video analysis revealed that tree
shrews had their tail significantly longer in an upright position at the beginning of a session (state
1), reflecting a high arousal state, compared to the end of a session (state 2). We acoustically
analyzed one chatter call per state of session per individual (n=20) to explore whether the arousal
state affect the acoustic quality of chatter calls specifically. The multiparametric sound analysis (17
acoustic parameters) showed that variations in acoustic parameters of chatter calls convey the
arousal state of a signaller reliably (Fishers Omnibus Test).
Higher arousal states are expressed by a higher number of syllables per call, by longer syllable
durations, by upward shifts in the fundamental frequency and by a less consistent acoustic structure
(Wilcoxon Signed Rank Test). Comparable results in mammals, including humans suggest that
generalized rules may exist in mammals to communicate the intensity of an affective state.
Contact information: Simone Schehka or email Simone.Schehka@tiho-hannover.de
Complete address: Institute for Zoology, University of Veterinary Medicine Hannover, Bünteweg 17,
30559 Hannover, Germany
Species: Tree shrew