Seems like a human eye is trained by evolution into "alertness" while in an alpha state

Is this alertness come from a more dangerous time?  Does this play a role in the drinking of alcoholic beverages???  I am not a drinker myself.  I am refering to the history of drinking in the world as a result of history and biology.  Does meditation offer another perspective???  Stability since nomadic life styles changed???  The use of pills today???  Driving???