It is generally accepted in the West that a distinct developmental period called “early adulthood” has been shaped by accumulating changes in societal dynamics during the past hundred years or so.One of its principal investigators is University of Pennsylvania Professor of Sociology Frank Furstenberg, whose more recent studies have been exploring the consequences of the more protracted journey young people must make into "full social adulthood" (arriving there at about the age of 34).He and his US colleagues hypothesized that just as the period of transition had become less orderly, so one might expect behaviors once associated with the teenage years to have spilled over.Criminal nuisance and substance use, for example, might nowadays be commoner among young people in their twenties and early thirties.But so far there is reassuringly little evidence of that "delayed desistance," according to Furstenberg's recent writing in the Journal of Research on Adolescence.The achievement of adult roles may be being pushed later, but the symptoms of adolescent uncertainty and distress seem to remain the preserve of the unhappy young.Furstenberg himself may be living proof of another societal dynamic – that longer lives allow longer lasting scholarship.His university career already spans four decades and shows no signs of let-up as he nears 70.He says an infatuation with information has followed him since childhood. “I loved data when I was a kid. I used to get the information almanac, you know, at Christmas time and that was my favorite present.” Happy coincidence kick-started his career. Growing up in a large extended family, he arrived at university with aspirations to be a psychologist. In his first term, he randomly signed up for a sociology course and, “It was like falling in love”. “Sociology made sense to me. It’s muddy and you have to have a high tolerance for ambiguity. But it’s a way of studying individuals and also how their environments influence them.”He credits the Columbia sociologist and early pro-feminist William J. Goode as having been his true inspiration. “Academic life has a familistic quality to it. There are good parents and bad parents, just as there are good mentors and bad mentors.”Furstenberg’s forays into longitudinal study were another fortunate accident. In the 1960s he began a study in Baltimore, observing and interviewing a group of teenage mothers. Little did he know he would still be interviewing them 30 years on. “I often say if I had known what I was getting myself in for, I never would have started,” he jokes. Because he has spent his whole career in a single institution focusing on one subject, one might expect Furstenberg’s work to be an exercise in refinement. But, on the contrary, his innate curiosity has led him to dodge monotony and disciplinary convention – and to trust diversity.