Page 32 - Deep Learning

The Need to Override Experience 15

true of our natural as of our social environment. Fires and wars; earthquakes
and market crashes; global warming and global trade; the connections go
deeper than mere analogy. The systems of which we are the parts unfold for-
ever in novel ways. There is nothing old under the sun.

LEARNING IN A TURBULENT WORLD

Sometime during hominid evolution, our species – more precisely, a hominid
species in the phylogenetic lineage that eventually produced Homo sapiens –
came to adopt an uncommon survival strategy. unlike other animals, they,
and hence we, came to rely more on learned skills than on innate dispositions.
certain aspects of human behavior have a genetic basis, but our behavior on
a typical day nevertheless consists primarily of actions that we had to practice
before we could do them – driving a car, using a telephone, sending e-mail –
and very few actions that we did not have to learn: smiling, blinking and little
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else. other animals learn as well, but we are more effective learners by far.
Even dolphins and chimpanzees, generally regarded as the smartest among
animals, cannot match the ease with which a human toddler soaks up new
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information and acquires new skills. Most important, we easily learn to use
tools and symbols, two keys to the astonishing progress of the naked ape we
once were; without stone axes, no space shuttles; without scratches on bone,
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no mathematics. We are not merely different from other animals in these
respects; we are orders of magnitude different.
The advantage of learned over innate skills lies in the speed of adaptation.
Both learning and biological evolution are mechanisms for tracking change in
the environment. When the material environment changes, it exerts novel
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selective pressures on any species that was adapted to that environment, and
over time such a species is molded by natural selection to fit the altered envi-
ronment. The change in the species mirrors the change in the environment,
and its phylogenetic lineage records the successive changes. Similarly, when
a person confronts changes in a familiar task, he prevails by adapting prior
skills to the new circumstances. The change in the skill mirrors the change in
the environment, and a person’s learning history records the challenges he has
faced throughout life. The similarities notwithstanding, these two mechanisms
for tracking change operate at different time scales: Evolution requires tens of
thousands of years, often more, to create a new anatomy and its associated life-
style, while learning operates over much shorter time periods, from minutes
to years. Species that rely primarily on innate skills and hence track change at
evolutionary rates become extinct eventually, victims of some environmental