Humans prefer being addressed in the right ear, and are more likely to perform a task upon receiving a request in the right ear rather than in the left one, suggest an Italian study.
Dr. Luca Tommasi and Daniele Marzoli from the University "Gabriele d'Annunzio" in Chieti say that the natural side bias, depending on hemispheric asymmetry in the brain, manifests itself in everyday human behavior.
One of the best-known asymmetries in humans is the right ear dominance for listening to verbal stimuli, which is believed to reflect the brain's left hemisphere superiority for processing verbal information.
But, thus far, the majority of research projects looking at ear preference in human communication have been controlled laboratory studies, and there is very little published observational evidence of spontaneous ear dominance in everyday human behavior.
Tommasi and Marzoli conducted three studies that specifically observed ear preference during social interactions in noisy nightclub environments.
In the first study, the researchers observed 286 clubbers while they were talking, with loud music in the background. They found that, in total, 72 percent of interactions occurred on the right side of the listener.
According to them, the results were consistent with the right ear preference found in both lab studies and questionnaires and they demonstrate that the side bias is spontaneously displayed outside the lab.
In the second study, the researchers approached 160 clubbers, mumbled something inaudible and meaningless, and waited for the subjects to turn their head and offer either their left of their right ear. The subjects were then asked for a cigarette.
Overall, 58 percent offered their right ear for listening and 42 percent their left.
Only women showed a consistent right-ear preference. In this study, there was no link between the number of cigarettes obtained and the ear receiving the request.
The third study saw the researchers intentionally addressing 176 clubbers in either their right or their left ear when asking for a cigarette. They obtained significantly more cigarettes when they spoke to the clubbers' right ear compared with their left.
Taken together, say the researchers, the results of the three studies confirm a right ear/left hemisphere advantage for verbal communication and distinctive specialization of the two halves of the brain for approach and avoidance behavior.
Based on their observations, they conclude: "Our studies corroborate the idea of a common ancestry, in humans and other species, of lateralized behavior during social interactions, not only for species-specific vocal communication, but also for affective responses."
A research article on the findings has been published online in Springer's journal Naturwissenschaften.