Saturday, 17 June 2017

Use it or lose it

Can you hold a pencil? Although not recognised as such by the Transportation Security Adminsitration, pencils can be used as a lethal weapon, if hexagonal they can also be used when there are no dice available, or to fish termites out of a hole for dinner. Chimpanzees could carry out any of those tasks but only humans can use a pencil to write their name . . . or The Grapes of Wrath. That's because we can use our thumb, index and middle finger in a 'power-precision grip' PPG and manipulate the pencil to make marks of tiny precision and delicacy - not only writing but drawings, graphs and diagrams that accurately convey and record meaning. Some drawings are so realistic that you wonder why the perp didn't use a camera. The PPG isn't only used for pencils but for lifting jam-jars, bullets, day-old chicks and baseballs. It is hard to program a robot's computer to pick up an egg without crushing but your muscle and mind achieve this without a conscious thought. It takes time to get these tasks right, babies are clumsy, can't get the spoon into their mouths and make a sloppy mess all round them until they learn how. Letting Petal feed herself is a long haul strategy but it pays dividends. Baby led feeding, adopted by The Boy and his family, saves a mort of money because the kids pick over the family dinner rather than being catered for with Gerber Glop, Materna milk puddings or Cow&Gate creamed rice. But BLF also drives the development of the mind, autonomy and a sense of self.

One of the things that neurologists are discovering is that the doors of perception need to be opened and closed, and frequently oiled, if they are to develop and retain utility. The brain is plastic and there are many potential calls on a neuron. After a stroke, you may laboriously recover the use of your limbs and the power of speech by re-purposing and recruiting other neurons to filfill the functions ablated by the ischemic event.  If you are born without eyeballs then the part of your brain destined to become your visual cortex is effectively snapped up by other functions and put to good use. This is an argument for embracing hearing-aids - to stop the auditory cortex closing shop altogether.  If you don't use your hands to carry out finely dextrous tasks then your don't get to keep the motor neurons and that may have negative impact on your general cognitive development.

When I was growing up we played with wooden cotton reels, saucepan lids and sticks, It was like reading the book rather than watching the film of the book. Our imagination filled in the bits between saucepan lid and shield; between Lego and Bridge of the River Kwai; between a plastic airplane and Dresden Valentine's Day 1945. Children then lived in their heads and could subvert efforts to make them play in particular ways - as exposed by Saki's story The Toys of Peace. The youth of today have no patience with wooden blocks or cardboard boxes because they have Lara Croft [bloboprev] to steer through somebody else's imagination.  David Gaul and his boss Johann Issartel at Dublin City University have got some data [PMID 26735589] on how the modern world may be turning the digital generation into blobs unable to zip up their own coats or pick their own noses because the only fine motor skill FMS they can carry out is a swipe or a tap.
Next time you see someone tying the shoe-laces just look at the task sequence required: it's a wonder that we can carry it off at all and I know my twin sister had to do this for me when we first went to primary school. Gaul and Issartel measured 250 kids divided between 2nd, 4th and 6th classes = aged 7, 9 and 11 and found that they got better at a standard set of motor coordination tasks as they grew up. That's good, you'd hope the young shavers were learning something over those 5 years.
Key: fine motor precision (FMP), fine motor integration (FMI), manual dexterity (MD) and upper-limb coordination (ULC). The bars are mean and for 2nd, 4th and 6th class. Quite a lot of variation there.  But concern developed when they compared the skills to the normal average for children of the same age:
Key: [annoyingly different from the tasks in Fig 2 above] fine manual control (FMC) and manual coordination (MC) units and Total Fine Motor Composite (TFMC). You can see that 2nd class students start off close to the average [the 50 line] but steadily fall behind 'normal' as they grow up. David Gaul was on the wireless the other day and he suggested this increasing deficit was a) disturbing and b) possibly due to the swipiness of the youngsters environment decreasing their capacity to do up a button let alone sew another one on when they oafishly rip the original one off trying to force it through the wrong button hole [I paraphrase!]. Skeptics among you will note that the error bars are all large and comfortably embrace the 50%=normal point on the standard score axis. Trouble with social science and medical experiments is that it takes yonks to gather up any kind of sample at all at all and even then it may not be statistically robust. The blue 2nd years are different people to the green 6th years and the difference in the means may be a statistical artifact. I hope that the authors aren't going to park the project having gotten this publication out because there is a longitudinal study crying out to be done: same kids tested at two year intervals. And of course, we need someone from Montpellier or Bordeaux to replicate the study in French schools. And a control set of home-educating children to see if school is sapping the will to live of the children who are ground through that inexorable mill. This reminds me of another place where the external environment impinges disastrously on neuro-musculat development - the myopia epidemic driven by the absence of sunlight.

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