Homo sapiens -- have a better sense of smell than their extinct Neanderthal cousins, which may be one reason why one thrived while the other died out, according to scientists.
Brain size is the same in both species, but differences in brain shape may indicate differences in brain organization that may be linked to behavior and cognition, which includes skills such as memory, problem solving, attention and producing and understanding language.
The international team of researchers used high-end imaging techniques to assess the internal structure of fossil H. sapiens and Neanderthal skulls. The scans revealed that modern humans have larger temporal lobes (involved in memory, language and social function) and 12 percent larger olfactory bulbs (involved in the sense of smell) than Neanderthals.
While other senses go through a number of brain filters, the sense of smell is directly connected to regions of the brain that process emotions, memory, fear, motivation, pleasure and 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," Katerina Harvati, of the University of Tubingen and the Senckenberg Center for Human Evolution and Palaeoecology in Germany, said in a university news release.
The better sense of smell in H. sapiens may be related to the evolution of social functions such as recognition of related people, enhanced family relations, group cohesion and social learning, Harvati and colleagues suggested.
"Although traditionally olfaction in primates and humans has been considered a less important sense, our study reevaluates its potential significance for human evolution, and particularly for the social evolution of our own species, Homo sapiens," they concluded.
The study appeared Dec. 13 in the online journal Nature Communications.