Re: AAT Theory

Daniel D Scripture (
3 Oct 1995 04:11:48 GMT

In article <44p3g9$> writes:
>In article <>, Paul Crowley
>>The problem has a hundred aspects; for example, consider the babies.
>>Baby apes can hang on to mother while she forages. Soon they can safely
>>clamber around the trees. Early hominid infants, with only two weak
>>grasping limbs, couldn't hold on; so the mothers had to use an arm to
>>carry them (or put them down) while foraging. And then the infants had
>>to learn to walk upright (with their short legs, wrong musculature,
>>weak spines, ill-adapted feet, etc.) Get the scene?
>A few years ago I saw an article in Scientific American (in their
>"science 100 years ago" column), where they referred to an experiment
>about how well newborn human babies could hold on to things. The
>result was that they are surprisingly good at it. The scientist(s) 100
>years ago noticed that babies, if given something to grasp, would
>hold on hard enough that it was possible to lift them with no other
>This was with babies who had to lift a lot more weight from their
>heads than any early hominid.
>Yes they had only two arms, as opposed to four limbs, to grasp with.
>But why do you assume that the arms were weak?
>Lisbeth Andersson, Sweden
About the grasping abilities of newborn humans--in the medical
profession in the U.S., at least, and I believe this is still current,
there is a series of ten or a dozen simple tests (the Apgar series)
performed on newborns
by U.S physicians immediately after birth.
The only one I remember is the one about grasping,
since I was so struck by it when I saw it done to my daughter some 23
years ago. The physician allows the child to grasp his or her little
fingers, and then lifts the child _completely_ off the bed. I was
startled--my daughter was then about ten minutes old, if that, and I
asked for an explanation of just what he was trying to find out, and
he said, "all healthy, full-term
newborns can fully support their own weight by
grasping with their hands. They _lose_ the ability within 24 hours,
however. Since the test is named after the 19th century American woman
physician who developed the series, this correlates with what you saw
in Scientific American, I would imagine.

What I have always wondered but never bothered to try to investigate is
whether the ability would go away if it were _used_. I can say that
human infants do have a strong tendency, especially when nursing, to
twine their hands into their mothers' hair, if it is long enough to be
within reach. In fact, they seem to lose that urge only when they
stop nursing.

Anybody know anything about this newborn grasping ability, and why it
goes away?

Dan Scripture
UC Santa Cruz