My understanding of economic rationality is that people act rationally to
maximize what they perceive to be their utility. Thus a "forbidden fruit"
hypothesis makes sense if and only if people believe they derive utility from
doing something which society at large finds unacceptable, by "virtue" of its
being unacceptable. To state the obvious, this might occur if a potential
drinker's peer group looked favorably upon such behavior, since acceptance by
one's peers is clearly a form of utility. Since some groups of young adults
do indeed view rebellious behavior this way, I see no inconsistency between
economic rationality and "forbidden fruit."
I would even go so far as to say that putting forth the appearance of being
rebellious is the primary purpose of a large portion of underage drinkers.
Because of laws against underage consumption, overall consumption might well
decrease in all classes of society, but those who maintained easy access to
alcohol would be more likely to binge drink -- after all, if drinking one
bottle of beer is rebellious, drinking two bottles is even more so. Thus
proportionally more underage drinkers binge drink. I also liked Mr. Parich's
argument that underage drinkers do not drink publicly and thus are less
likely to know when to quit.
Hopefully, these observations help explain why binge drinking has increased
even as overall consumption has decreased.
--Brian Auriti