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Right Ear

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Daniele Marzoli1 and Luca Tommasi1 Contact Information
(1) Department of Biomedical Sciences, University “G. d’Annunzio”, Blocco A, Via dei Vestini 29, 66013 Chieti, Italy

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  • 1. Naturwissenschaften (2009) 96:1099–1106 DOI 10.1007/s00114-009-0571-4 ORIGINAL PAPER Side biases in humans (Homo sapiens): three ecological studies on hemispheric asymmetries Daniele Marzoli & Luca Tommasi Received: 16 January 2009 / Revised: 20 May 2009 / Accepted: 26 May 2009 / Published online: 20 June 2009 # Springer-Verlag 2009 Abstract Hemispheric asymmetries and side biases have Mandal et al. 2000; Brancucci et al. 2009) but also in many been studied in humans mostly in laboratory settings, and other vertebrate species (Rogers 1999; Rogers and Andrew evidence obtained in naturalistic settings is scarce. We here 2002; Tommasi 2009). Among the many classes of report the results of three studies on human ear preference lateralized behaviors discovered thus far, side biases during observed during social interactions in noisy environments, interactions between conspecifics have been observed both i.e., discotheques. In the first study, a spontaneous right-ear in lower and in higher vertebrates (Bisazza et al. 1998; preference was observed during linguistic exchange be- McKenzie et al. 1998; Sovrano et al. 2001; Zucca and tween interacting individuals. This lateral bias was con- Sovrano 2008), as well as in humans (Turnbull and Lucas firmed in a quasi-experimental study in which a confederate 2000; Güntürkün 2003) and in other primates (for a review, experimenter evoked an ear-orienting response in bystand- see Damerose and Vauclair 2002). ers, under the pretext of approaching them with a whispered One of the best-known asymmetries in humans is the request. In the last study, subjects showed a greater right-ear dominance for listening to verbal stimuli (e.g., proneness to meet an experimenter’s request when it was Bryden 1988; Kimura 1961), which is associated with a directly addressed to the right rather than the left ear. Our general right-ear preference in tasks requiring the use of a findings are in agreement both with laboratory studies on single ear (e.g., Ida and Mandal 2003; Porac and Coren hemispheric lateralization for language and approach/ 1981). Many laboratory studies and particularly those avoidance behavior in humans and with animal research. employing the dichotic listening method (the simultaneous The present work is one of the few studies demonstrating presentation of two different stimuli to the ears) have the natural expression of hemispheric asymmetries, show- evidenced a right-ear advantage in several linguistic tasks. ing their effect in everyday human behavior. Since the early reports of Kimura (1961), this advantage has been documented in right and left handers, in adults and Keywords Side bias . Ear preference . Behavioral children and in both sexes (Bryden 1988; Hiscock 1988; lateralization . Communication . Hemispheric asymmetries . Hugdahl et al. 1990). Furthermore, a small but significant Approach/avoidance behavior . Homo sapiens right-ear advantage was reported for recognition of words presented to the left or right ear in the presence of continuous binaural white noise (Young and Ellis 1980). Introduction According to Kimura (1967), the right-ear advantage in dichotic listening tasks with verbal stimuli reflects the left It is now well-established that perceptual and motor hemisphere superiority for processing verbal information. asymmetries exist not only in humans (for reviews, see This depends on the fact that the contralateral auditory pathway suppresses the ipsilateral pathway, so that the D. Marzoli : L. Tommasi (*) right-ear input to the left hemisphere would be advantaged Department of Biomedical Sciences, University “G. d’Annunzio”, with respect to the left ear input to the same hemisphere Blocco A, Via dei Vestini 29, 66013 Chieti, Italy (Kimura 1967). Moreover, the transfer of the input from the e-mail: luca.tommasi@unich.it left ear to the left hemisphere across the corpus callosum

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