During today's meditation I realized that the reason why it is so difficult to stay alert and focused is that the brain constantly seeks stimulation. I've read about this before but it never appealed to me as strikingly as it did this morning. When I started bringing my attention to the distractive nature of my mind, it began to vanish. I became extremely calm and moved deeply into the now. There wasn't a spark of boredom - not in terms of dullness, but agitation.
There are three needs which the flow of attention depends upon according to Rick Hanson's fantastic book "Buddha's Brain" (view excerpt). He states that the brain balances "keeping information in mind, changing the contents of awareness, and finding the right amount of stimulation", which I had understood rationally before, but today for first time have been able to directly observe.
Thinking about it later, Maslow's hierarchy of needs came to my mind and how a hungry person can hardly understand first world problems. In fact the hunger never ends. Once you have eaten your fill, it is the mind that continues to agitate. To a certain extent this is legitimate when providing for risks or building up stocks. But in a world of stress and shortage of time, it is wise to critically reconsider what we strive for. Is it a true necessity or merely a chimera of the brain?