In this TED talk, Jill Bolte Taylor describes in detail a brain hemorrhage that she suffered in 1996. In the talk, she describes how the brain is divided into two hemispheres—the left hemisphere and the right hemisphere—and she explains the function of each half. The left hemisphere in the brain, she says, is "all about the past and all about the future," and its purpose is to form the sense of self that we know ourselves by. The left hemisphere essentially creates our ego, our fundamental identity, from the collection of moments which make up our past and in anticipation of the moments which might make up our future. The right hemisphere, on the other hand, is "all about the present moment," and it processes information in the form of energy filtered through all of our senses.
At the end of the speech, Taylor says that we can choose which hemisphere to "step into" at any given moment. We can choose the consciousness of our left hemisphere where we become "a single individual," separate from everybody else, or we can choose the consciousness of the right hemisphere where we are connected to everyone and everything else through the energy that we all feel and decipher as sensations, where we, thus, can "be at one with all that is."
In Lord of the Flies, Jack and Ralph can be interpreted as representing the two sides of the human brain or, more broadly, the two sides of human nature. Jack represents the left hemisphere, which is all about the self and the projection of the self onto the world. Ralph (and also Piggy) represents the right hemisphere, which is all about realizing that we are connected to everyone else and that, as Taylor might put it, we are all a part of the same energy. Indeed, one of the morals of Lord of the Flies is that we should be less egocentric, less concerned with consolidating and bolstering the self, and more concerned with connecting to the energy that binds all of us together. This latter state of being is what Taylor, in her TED talk, calls nirvana: a Buddhist term meaning a total transcendence of the self and a consequent loss of suffering and desire.