I can't speak for the other apes (or any animals come to that) but through observation I've noticed that there are certain things that must happen (i.e. be learned) by certain ages or a chance is lost forever.
Baby birds, for example, imprint on their parents (which might not be their parents or even another bird) and that bond lasts for life. (I've exploited this with hand-reared parakeets - but the onset of adolescence creates further problems - something I expect is to due with the evolutionary need to leave the coup.)
Humans seem to lose the ability to fully learn language unless we are exposed to it at a very early age; similarly, bad habits not broken by the early 20s are difficult if not impossible to overcome.
Some areas of our brains seem more plastic than others - scientists have recently discovered that musical memory seems to be stored separately to other memories. (http://www.bbc.co.uk/news/magazine-15791973)
I wonder if anyone knows of any studies which actually pinpoint the various ages that these events occur?
I'm particularly interested in language development - since I suspect that we're teaching languages far too "late" and the rare polyglots among us are examples of people whose brains have not "hardened".
This is actually a very heavily studied field of neurobiology/cognitive psych, especially with respect to language acquisition and the visual system. The technical term of what you're referring to is a "critical period". There are entire textbooks on this theory and the related studies. So, if you google it I assure you, you will find mountains of reading. :)
Although not exactly related to your question, I read this paper a couple of years ago and found it quite interesting.
Fab, thank you. I'm suffering with reduced cognitive function right now (seriously) so this is helpful.
I think some brains are more plastic than others. In that some people have more capacity to learn and for longer into adulthood also.... albeit slower than a child might... :)
This is what makes me so curious.
Suzanne's links should provide some interesting reading (and have) but I suspect that while we can learn somethings later in life by rote, many things are set in place - some much, much later than others. In my example above - could it be that polyglots are naturally able to absorb new lanugages simply because their brain's language centre remain plastic throughout their lives?
Poor behavior in adults seems traceable to poor parenting skills - and very little can be done to break these "habits" once the adult passes the mid twenties.
A fuller understanding these things could help us raise better children and explain (even partly) why memes and memoryplexes are so difficult to shift.
To address the language thing again, yes, there are many studies implying that the bilingual brain has structural differences than the monolingual one. I recall reading about an fMRI study (which I can't find at the moment) which showed that someone bilingual in childhood activated roughly the same area of their brain for both languages, but someone who acquired a second language in adulthood "stored" that language in an entirely different region. It would be too much of a jump to say that this implies an extended period of plasticity, but you can say that their brains do process language in a very different way, one which may lend itself more easily to acquisition of additional languages.
Some limited information on the bilingual brain is given here: http://www.sfn.org/index.aspx?pagename=brainbriefings_thebilingualb...
Alice also raises an interesting question re: some brains remaining more plastic than others. Not sure how one might go about studying this, though, or exactly what "more plastic" would mean, on a cellular/molecular level... (ahh, must stop myself before I go into even more of an all-out incomprehensible nerdrant!)
I know that I pick up new knowledge and understand it in complexity more easily than others. My husband is very slow to pick up new information, but once retained it's much more strong - in the long run he walks all over me - but I'm much better at quick learning and understanding.
I read a book about gut flora that suggested that our gut flora make up inpacks our brain function. The bacteria in our gut is responsible for producing histamines that assist brain function - we don't produce it ourselves and are dependent on bacteria to do this for us - otherwise our brains couldn't function. So the make up of our gut flora would have a big impact on our brain function. As far as I can work out, more can lead to anxiety, and other mental disorders, too little I presume would mean that we were quite slow? Not sure. But optimal might be enough to have quick thinking, but not too much that we became mentally unstable. Gut flora comes from birth and our immediate environment after birth. It is apparently difficult to change our gut flora, we can adjust it with pro biotic tablets and foods and damage it with alcohol, medication etc.
Interesting point about gut flora there - wonder if that has any connection with the steady decline in acute appendicitis that we've seen since ... the 1950-60s (IIRC).
I think might be worth designing an experiment to see if this type of brain plasticity is learned, innate or something in between - unless Suzanne has seen any studies on it?
And Suzanne, by all means go all Nerdranty on us - we love it!
probably a bit of both nature and nurture - as always.... :) but you need prerequisites to be educated... but if you work really hard you might get good at something you're not born too... but the working hard must be born with I suppose..... it's a synergy