I certainly know the diminishing inclination to take (at least certain kinds of) risks as one gets older. And there may well be less I-function inhibition of the cognitive unconscious when one is younger. My guess though is that at least some of the change has to do not with a strengthening I-function but rather with a cognitive unconscious that is altered by experience. Its my unconscious rather than my I-function that inclines me to avoid things now I might not have avoided years ago. I just don't feel like doing them.