We hear all the time that through experience and age, people get wiser. Often, wisdom (a rather abstract, intangible construct) is conflated with intelligence. Therefore, people often believe that as they age, they become wiser, and are therefore more intelligent than younger people. Additionally, they believe that their future self is more intelligent (or "wiser", as they like to say) than their current self. During arguments between a younger and older individual (I am not speaking of fruitless parent-child bickering.), the older individual may simply discount the former's opinion, because he is too young. "You'll understand when you are older."... "How old are you?? 18 (with an IQ of 140)? HAH!"
In my opinion, experience, in and of itself, is neutral, though, still a positively-affecting variable. Experience can condition people to act intelligently (defined as using one's faculties to efficiently acquire a personal objective) or irrationally. Additionally, proper knowledge is more important than experience. When combined with experience, quality knowledge on a subject creates an adept quality within an individual, or even expertise. In fact, a college undergraduate who has taken a couple of psychology courses in a quality institution is better than a public school teacher, who with a degree in education, has taught psychology out of a high school textbook for 35 years. The experience, in this case, did not assist the public school teacher. The coursework he teaches was covered in the first two weeks of the undergraduate student's intro class.
This concept can be applied to choices as well. An intelligent person doesn't need to live through idiotic experiences, only to find that their choices led them there; they understand the relationship between cause and effect. People who tout "experience" and "wisdom" would claim that their poor experience with their first spouse (who showed signs of Borderline Personality Disorder--any layperson can detect signs of borderline psychosis) taught them a life lesson. Indeed, they shall never make that mistake again! Someone who is smarter would have ended the relationship, because such a person understands that short-term feelings are not worth future, long-term stress. Cause and Effect.
An intelligent person lives life more efficienty, as they do not have to waste many hours partying, only to realize that the partying detracted from their studying--thereby depleting their grade averages, which depletes their total GPA needed to get that job they wanted. An intelligent person sees the "roadmap" or "layout" of each situation before them. People who waste time with experience end up wasting their life, whilst LEARNING NOTHING. Such a person must live through each bad experience to learn from it, whereas a rational person would have made the correct choice beforehand.
It is a cultural norm to believe that "wisdom", "experience", and "life" are tangible, objective qualities. It seems that many older people use experience as a guise; they like to believe that they are more intelligent than they are. Perhaps, even then, the idea that experience = wisdom = IQ increase is a byproduct (or, even product itself!) of a rationalization: telling oneself that he is smarter than he was "before", because he is older.
tl;dr version: Idiots r idiots 4 lyfe