, Volume 96, Issue 9, pp 1099–1106 | Cite as

Side biases in humans (Homo sapiens): three ecological studies on hemispheric asymmetries

  • Daniele Marzoli
  • Luca TommasiEmail author


Hemispheric asymmetries and side biases have been studied in humans mostly in laboratory settings, and evidence obtained in naturalistic settings is scarce. We here report the results of three studies on human ear preference observed during social interactions in noisy environments, i.e., discotheques. In the first study, a spontaneous right-ear preference was observed during linguistic exchange between interacting individuals. This lateral bias was confirmed in a quasi-experimental study in which a confederate experimenter evoked an ear-orienting response in bystanders, under the pretext of approaching them with a whispered request. In the last study, subjects showed a greater proneness to meet an experimenter’s request when it was directly addressed to the right rather than the left ear. Our findings are in agreement both with laboratory studies on hemispheric lateralization for language and approach/avoidance behavior in humans and with animal research. The present work is one of the few studies demonstrating the natural expression of hemispheric asymmetries, showing their effect in everyday human behavior.


Side bias Ear preference Behavioral lateralization Communication Hemispheric asymmetries Approach/avoidance behavior Homo sapiens 



This research is part of the project EDCBNL (Evolution and Development of Cognitive, Behavioural and Neural Lateralization—2006/2009), supported by the Commission of the European Communities within the framework of the specific research and technological development program “Integrating and strengthening the European Research Area” (initiative “What it means to be human”), through a grant to LT. We thank Assia Liberatore and Lucia Vangieri for their precious help in collecting part of the data.


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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of Biomedical SciencesUniversity “G. d’Annunzio”ChietiItaly

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