In an attempt at a one sentence definition of infantilisation, I'd go for:
"The adoption, by adults or mature adolescents, of iconography that is, or was initially, intended for children."
"Aha!" I hope you say - it's clear the kind of thing I'm on about here. Hello Kitty. Bagpuss. Pink plastic jewellery on 27 year-old. Alcopops. "Girl power". Mugs with cartoons on them saying “Dizzy Bint!” or something. The list is endless.
This cultural phenomena is partly employed with an ironic twist, as is everything worth its salt in the Postmodern era. These fads and fashions are usually knowingly tongue-in-cheek. It's all part of the now common adoption of seemingly random cultural iconography where the original meaning is either lampooned or just plain chucked out and replaced.
Why is this happening? The answer that I'd give, mainly based upon the experiences of myself and others, is that for many young people, the world of adulthood is imposing in the extreme, and it is also almost impossible to define the moment when you become an adult. In this way, childhood becomes drawn out and extended as long as possible, simply because there's no clear point defined by society to say when it should stop. In other words, there is no longer a notion of 'coming of age'. The age based barriers, usually 18 and 21, are not given much importance outside of big birthday parties or the law. Certainly not enough of a change in the way an individual relates to society is present to stave off the notion that we're still at a stage of not being a Proper Grown Up. True, we may have a job, a car, a house or even kids, but damn, we're still not this mythical Proper Grown Up.
In a life without such societal hurdles, the feeling that "20 isn't that much different from 21, which isn't too different from 22, which feels the same as 23..." raises its head, and the end to childhood and adolescence becomes an endless smear, waiting to be formally stopped at some undefined point in the future.
Another aspect to infantilisation in our culture, which is chiefly a product of the media and commerce, is false nostalgia. Bearing an uncanny resemblance to false memory syndrome, false nostalgia is what I call the product-driven fad that is created by some advertising gimp and quickly adopted by late teens and twenty somethings. The prime targets (at least in the UK) are students, who are re-sold the experiences of their youth. Mainly in the form of merchandise based upon old kids TV shows. Strangely, these will often be shows for pre-school kids, and often shows that the fad victim never actually watched. It is of course here where irony is at its strongest, such as the 'adult' version of Rainbow that does the tour of student unions during the fresher's week of entertainment. Har Har. Zippy said “bollocks”. My sides are splitting.
Is there some link between this and the fact that the main market/most infantilised group of society is, by and large, that which has just left home for the first time? The presence of such fads and iconography could be seen as a safety blanket against the shock of the new.
In short, a whole new aesthetic seems to have been born in the early 90's, one that is a knowing and ironic version of childhood or the icons of childhood. It's now ubiquitous in the sections of the media and pop-culture that deal with young adults, and it looks like it will stay. I find it pretty creepy, to be honest, as with most of the Postmodern, ironic, mish-mashed part of the Zeitgeist, it seems to remove any potential for anything to be treated seriously. If seriousness and responsibility are the marks of adulthood, then a reactive infantilism as an attempt to cope with adulthood damages any hope of overcoming the problems it sets out to deal with. The response to a real problem has become a malignant problem itself.