Sex-specific asymmetries in communication sound perception are not related to hand preference in an early primate
Marina Scheumann1,2 and Elke Zimmermann1,2
1Institute of Zoology, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany
2Center for Systems Neuroscience, Bünteweg 17, 30559 Hannover, Germany
BMC Biology 2008, 6:3. This is an Open Access article distributed under the terms of the Creative Commons Attribution License.
Left hemispheric dominance of language processing and handedness,
previously thought to be unique to humans, is currently under debate.
To gain an insight into the origin of lateralization in primates, we
have studied gray mouse lemurs, suggested to represent the most
ancestral primate condition. We explored potential functional
asymmetries on the behavioral level by applying a combined handedness
and auditory perception task. For testing handedness, we used a forced
food-grasping task. For testing auditory perception, we adapted the
head turn paradigm, originally established for exploring hemispheric
specializations in conspecific sound processing in Old World monkeys,
and exposed 38 subjects to control sounds and conspecific communication
sounds of positive and negative emotional valence.
The tested mouse lemur population did not show an asymmetry in hand
preference or in orientation towards conspecific communication sounds.
However, males, but not females, exhibited a significant right ear-left
hemisphere bias when exposed to conspecific communication sounds of
negative emotional valence. Orientation asymmetries were not related to
Our results provide the first evidence for sex-specific asymmetries
for conspecific communication sound perception in non-human primates.
Furthermore, they suggest that hemispheric dominance for communication
sound processing evolved before handedness and independently from each