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Brain form reveals: Homo sapiens has a better sense of smell than Neanderthals
12 December 2011
An international team, including researchers from the University of Tübingen and the Senckenberg Gesellschaft für Naturforschung in Frankfurt used high end imaging techniques to reveal differences in the brain form that concern the sense of smell.
Two different human species, Neanderthals and modern humans, have independently evolved equally large brains. Although their brains are not distinguishable in terms of size, differences in brain shape might indicate differences in brain organization that may be linked to behavior and cognition.
An international collaborative study led by the Spanish Natural Science Museum with the cooperation of Prof. Dr. Katerina Harvati of the University Tübingen and the Senckenberg Center for Human Evolution and Palaeoecology was published today in Nature Communications (DOI 10.1038/ncomms1593). High-tech medical imaging techniques and 3D morphometrics were used to access internal structures of fossil human skulls and to quantify the shape of their brains as reflected in the form of the cranial base.
This study revealed that the temporal lobes, involved in language, memory and social functions, as well as the olfactory bulbs, involved in the sense of smell, are relatively larger in H. sapiens than in Neanderthals. The authors note that ‘The brain structures which receive olfactory input are approximately 12% larger in H. sapiens than in Neanderthals.’ These findings may have important implications for olfactory capacity and human behavior.
Olfaction is among the oldest senses in vertebrates. While other senses must pass through different cortical filters, olfaction goes from the environment directly to the highest centers of the brain. It goes to regions responsible for the processing of emotions, motivation, fear, memory, pleasure and also sexual attraction.
“The sense of smell is directly linked to memories to an extent that no other sense is. This explains why smells immediately incite strong emotions concerning past events and also strong feelings about people” explains Prof. Katerina Harvati, one of the study’s investigators.
The relatively larger olfactory bulbs and temporal lobes in Homo sapiens compared to any other human species may point towards an improved sense of smell, possibly related to the evolution of social functions, such as kin recognition, enhanced family relations, group-cohesion and social learning.
“Although traditionally olfaction in primates and humans has been considered a less important sense, our study re-evaluates its potential significance for human evolution, and particularly for the social evolution of our own species, Homo sapiens” state the authors.
The image shows the base of the brain in modern humans as transformed from the average brain of early Homo. Foto: 3D Morphometrics Lab, Paleoanthropology Group, Museo Nacional de Ciencias Naturales, CSIC