The right-ear advantage for verbal stimuli shows the left hemisphere's specialization for language. According to a 1973 study, speech presented to the right ear in dichotic presentation shows stronger control over language mechanisms in the left hemisphere than the left ear. This shows that the act of competition between each ear is key, as right-ear advantage does not exist when sounds are presented one ear at a time. Another study in 1980 shows that the advantage in right handers is only restricted to a few consonants, but not any vowels.

Further Explanation of the Right-Ear Advantage in Dichotic Presentation

In a task where a participant is told to identify/recall the different sounds coming through each ear, most people will identify sounds that come from the right ear more accurately than the right ear. (Note: 50%of left-handers experience the reverse, which is a left-ear advantage).



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In healthy individuals, studies on brain asymmetry focus primarily on hearing and vision. By directing auditory or visual stimuli to a single hemisphere, researchers can infer functional specializations based on the participants' responses.

Information Processing in the Left and Right Brain Hemispheres

Dichotic presentation is where participants listen to two different streams of dialog delivered simultaneously to the left and right ears.

Dichotic Presentation

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

The Right-Ear Advantage in Dichotic Presentation

Using a tachistoscope test, stimuli is presented to either the left or right visual field for less than 150 milliseconds to have the input only in the contralateral hemisphere.

These studies confirm the general division of labor between the hemispheres. The left hemisphere(right visual field) is better at processing verbal stimuli (letters and words). The right hemisphere (left visual field) is better at processing non-verbal stimuli (faces, geometric words, etc.). Simple visual detection is performed by both hemispheres.

Visual Perception of Linguistic Stimuli

During the experimental task of dichotic presentation, subjects are asked to focus attention on one ear or the other while stimuli are being presented separately to both ears. Participants could accurately report what they were hearing in the attended ear, but they could report very little that had been presented to the nonattended ear. 

Dichotic Presentation: Shadowing

An interesting phenomenon regarding to event-related-potentials is noticeable during dichotic presentation. Overall, the ERP's for attended stimuli were larger in amplitude than when the same stimuli at the same ear were not being attended to. This N1 effect must have been caused by selective attention somehow acting on neural mechanisms to enhance processing of information from that ear. The prefix "N" refers to the negative voltage deflection of the event-related potential.

N1 Effect

This is another ERP , event-related-potential, finding based on the dichotic presentation studies. P3, a wave also called auditory P300, is believed to reflect higher-order cognitive processing of the stimulus (ie. semantic meaning of words, identification of the speaker, etc.). The P3 effect is an example of a late-selection effect of auditory attention. The prefix "P" refers to the positive voltage deflection of the event-related potential.

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