by Martha Stark, MD / Faculty, Harvard Medical School


It is generally accepted that engaging both sides of the brain will promote hemispheric synchronization and optimization of brain functioning, which has been shown to improve overall physical and mental well-being and to optimize physical and mental performance (Lombard 2009).


Interestingly, most people favor one hemisphere over the other, although electroencephalographic (EEG) studies have demonstrated that humanity’s greatest philosophers, thinkers, inventors, and artists use both hemispheres together (Church 2014).


So how can both sides of the brain be activated at the same time in order to facilitate both mindful retrieval of old bad and intentioned commitment to new good, such that those experiences (one deriving from the past and the other deriving from the present) can be repeatedly and forcibly juxtaposed and there can be opportunity for the updating of old, maladaptive narratives (namely, therapeutic memory reconsolidation)?


Because each hemisphere has sensory and motor control of the opposite side of the body, moving both sides of the body at the same time and in a rhythmic fashion will facilitate brain integration, as happens, for example, with walking, playing the piano, typing on a keyboard, or knitting. Even more facilitative will be cross-lateral movements, which involve crossing the midline of the body with an arm and/or a leg in order to engage both sides of the brain in a balanced fashion and to strengthen the corpus callosum.


Brain gym exercises are also useful. And if you can learn to be more ambidextrous, it will promote hemispheric synchronization. On average, ambidextrous people are more adaptable and more emotionally resilient.


Alternatively, one can practice any of the following exercises (using both hands simultaneously): stir two cups of coffee, pick up two objects, catch two balls, throw two wads of paper into a waste basket (tossing one overhand and the other underhand), draw two pictures, write with both hands, and learn to juggle.


Interestingly, if shown the words for colors but with word and color mismatched, your right brain will try to say the color, whereas your left brain will insist on reading the word.


At any given moment, one of your nostrils is more open than the other, and this alternates in a rhythmic fashion over the course of the day. When your right nostril is more open, brainwave activity is greater in the left brain; by the same token, when your left nostril is more open, brainwave activity is greater in the right brain. In other words, whenever the nostril dominance switches, so does the activity of the brain hemisphere. Hemispheric dominance therefore naturally shifts back and forth over the course of a day.


You can deliberately shift hemispheric dominance by closing one nostril and focusing your attention on breathing through the other nostril. As an exercise, do alternate nostril breathing to balance out your brain.


Parenthetically, comparing the temperature in one ear to the temperature in the other (using a sensitive aural thermometer) provides a clever and convenient way to assess hemispheric dominance. Fred Schiffer (1999) has made the fascinating discovery that when one side of the brain is being preferentially activated, then blood flow on that side will be shunted away from the ear to the more centrally located cerebral cortex, such that the temperature in the ear on that side will become somewhat lower than the temperature in the ear on the side of the brain not being activated!


When both sides of the brain are stimulated with bilateral alternating stimulation, an aural thermometer will indeed easily demonstrate equalization of the temperatures in the ears, signifying hemispheric synchronization and optimization of brain functioning (Schiffer 1999).


Along these same lines, Marcel Kinsbourne (1983), a prominent neuroscientist at Tufts University, performed a remarkable study in which he demonstrated that when subjects were asked to perform a verbal memory task, which is primarily a left-brain function, they performed better when gazing to the right. Kinsbourne ultimately concluded that looking to the right stimulates the left brain and looking to the left stimulates the right brain, which means, at least in theory, that you can manipulate the side of your brain that you want to be more active by looking in the opposite (contralateral) direction.


So when you want to win an argument with somebody, stand to their left so that you can look to your right, which has the advantage of not only engaging your rational left brain but also forcing them to use their emotional right brain (Kinsbourne 1983).


Years earlier, Roger Drake (1985) and his associates at the University of Colorado had conducted a number of studies in which they too found that subjects could do a verbal task faster if they gazed to the right (thereby engaging their left brain) whereas the subjects could do a spatial task more quickly if they gazed to the left (thereby engaging their right brain). They too had concluded that you could affect which side of your brain would become activated by simply looking to one side or the other.


Although these various studies are intriguing, obviously more scientific research will need to be conducted over time. But what this research does accomplish is to highlight what, intuitively, many of us probably already know, namely, that the two sides of the brain are responsible for different functions and can be subtly manipulated in order to optimize their functionality. 




Church D. 2014. The Genie in Your Genes: Epigenetic Medicine and the New Biology of Intention (3rd ed.). Fulton, CA: Energy Psychology Press.


Drake RA, Bingham BR. 1985. Induced lateral orientation and persuasibility. Brain Cognition 4:156-164.


Kinsbourne M. 1983. Lateral input may shift activation balance in the integrated brain. Am Psychol 38(2):228-229. doi: 10.1037/0003-066X.38.2.228.


Lombard J. 2009. Balance Your Brain, Balance Your Life. Hoboken, NJ: Wiley.


Schiffer F, Anderson CM, Teicher MH. 1999. Electroencephalogram, bilateral ear temperature, and affect changes induced by lateral visual field stimulation. Compr Psychiatry May-Jun;40(3):221-225. doi: 10.1016/s0010-440x(99)90007-x.