Test yourself: your dominant ear

In my last posting on Attention and Distraction I hinted that sticking your finger in your ear can tell you more about how you hear and process sounds. It can demonstrate how you get easily distracted, but it also can tell you something about how you process language and produce speech.

So let’s start again. Being in a situation where you are listening to a person, put your right finger into your right ear (as shown by our left side Obama twins), and notice how easy, or difficult, it is to continue following the conversation. Now reverse the ears, or rather reverse the fingers, by putting your left finger in your left ear and notice how easy, or difficult, it is to continue following the conversation.

Obama Right and Left EarThe difference may be negligible for you, or it can be more pronounced. If it is small and you can easily follow the conversation with either ear closed, great, you’re doing well. For many people following the conversation with the left ear closed will be easier than with the right ear closed. This is because most people process language in the left side of the brain and sounds from the right ear go directly to that left side, while sounds from the left ear go to the right side of the brain that doesn’t understand language.

So how come we can still understand language with our right ear closed? Good question. Well, in our brain the two sides do communicate with each other and language that is received by the language dumb right side, gets transferred through the Corpus Callosum the the language savvy left side. But this transfer takes time and if it’s a bit slower than usual, it may lead to a reduction in processing speed and thus language understanding.

If it’s easier for you to follow a conversation with your right ear closed, and you’re thus listening with your left ear only, then you are probably left-ear dominant. That is absolutely fine if you have no language or speech problems. I, myself, are strongly left ear dominant, but I seem to manage very well in both my understanding of language and being able to speak fluently. For some, however, left-ear dominance combined with a slower than usual inter-hemispheric transfer speed can cause speech and language difficulties. This can be slower understanding, difficulties with multiple instructions, memory problems or speech impediments such as unclear speech or stuttering / stammering.

Our research focus is very much on this area of ear dominance, auditory processing and inter-hemispheric coordination and transfer. Our quest is to find long lasting, effective and practical ways to improve this processing in the brain – hence the birth of the SAS methodology. Below I reproduce some sections of the SAS for scientists and scholars posting that provides the scientific underpinning to our methodology.

Right ear advantage for language processing may be caused by several interacting factors. The left hemisphere, especially for right-handed individuals, is specialised in language processing. Kimura postulated that auditory input delivered to the left ear, which is sent along the ipsilateral auditory pathways, is suppressed by the information coming from the right ear. Input to the left ear, which first reaches the contralateral right hemisphere, must be transferred via the corpus collosum to the left hemisphere where the language processing areas are located. The transfer of linguistic information from the right hemisphere to the left hemisphere results in a slight delay in processing. No such transfer delay is found for the right ear, thereby favouring the right ear for speech processing. [Kimura, D. (1961), Cerebral dominance and the perception of visual stimuli, Canadian Journal of Psychology, 15(3), 166-177].

There is evidence of differences in linguistic processing between people who stutter and people who do not stutter. [Ward, D. (2006), Stuttering and Cluttering: Frameworks for understanding treatment, Hove and New York City: Psychology Press].

Brain scans of adult people who stutter have found increased activation of the right hemisphere, which is associated with emotions, than in the left hemisphere, which is associated with speech. In addition reduced activation in the left auditory cortex has been observed. [Gordon, N. (2002), Stuttering: incidence and causes. Developmental medicine and child neurology, 44 (4): 278–81] [Guitar, B. (2005), Stuttering: An Integrated Approach to Its Nature and Treatment, San Diego: Lippincott Williams & Wilkins].

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