GREGORY BENFORD
IS IT SMART TO BE SMART?
IS IT SMART to be smart?
Of the billion species that
have thrived on Earth since the first cells, we are
the only one to achieve high
intelligence. Medium-higher levels appear only in
other primates, some carnivores, and
whales. It would appear that getting
smarter has not been a wise career move for most
animals.
Evolution rewards getting one's genes into the next generation. All life is in a
furious competition to make copies of itself -- actually, half-copies, for
sexual
reproduction (which is not just fun, but the preferred mode among all
animals) carries
forward only half the genes of each parent.
One need not be a cliche intellectual
wallflower at the high school dance to
suspect that intellect is far down on the list for
selection.
This has implications for the Search for Extraterrestrial Intelligence, SETI.
Big brains are not so much an advantage that they have been invented repeatedly.
This is
how evolutionists usually evaluate a property: by asking whether it
developed often.
Generally,
the number of times an ability appears is driven by both how easy it
is to get, and how
useful it is. Eyes (or at least well-developed light-sensing
equipment t appeared
independently at least forty times in widely varying
organisms. Similarly for hearing,
binocular vision, and other useful tricks.
Of course, high intelligence has a high down
payment. The only way we know to
develop intelligence lies in having big-brained children,
who can learn varied
responses to their world. This proves, in us, a better route than
embedding in
our genes elaborate programs which tell us how to hunt, forage, mate, etc.
But
big-brained children then require lots of care-giving time from their
parents. Somebody
must feed them while they learn artful ways of feeding
themselves.
So slight increases in
intelligence had better pay off from the first, giving a
species a decided advantage in the
genetic sweepstakes. Running big brains also
eats up calories, as we'll see later.
Homo
sapiens has been around roughly 300,000 years, only six percent of the time
that hominids
have tramped across Africa. (A hominid is any primate between
ourselves and the chimps; all
the others are now extinct.) We have been clever
enough to build radios for only one
century. Can we readily expect to hear radio
signals from similarly smart species
elsewhere? How common can we expect
intelligence to be in the galaxy?
There are many ways to
approach the intriguing questions which emerge from such
ideas. Why did tree-dwelling
shrews of 65 million years ago, minor bit players
in the jungle drama, evolve into us
big-brained lords of creation?
One method is to ask how rather than why -- why not in the
"who caused this?"
sense, but in the "what over-arching principle made this happen?" sense.
Plainly
natural selection is at work, but what mechanism does it use, in this case?
Asking
the question this way is less vulnerable to the charge that we are simply
telling "Just-So
stories" to make the mysteries of vast time scales seem
understandable. Big brains are
useful for processing external stimuli and for
formulating models about those data, and
even for telling one's fellows about
these ideas.
But how does an organism get the big brain
to do these marvelous things? Would
extraterrestrials follow the same path?
Suppose we
approach brains as an engineering problem. A new-born's brain burns
about 60 percent of its
intake energy, a huge investment in a gray nugget that
doubles in size in the first year.
Rather than focus on the advantages of big
brains, their huge energy consumption argues
that evolution always had to
consider tradeoffs. Our brains three million years ago were
about the size of a
modern-day chimpanzee's, and have tripled since, while our bodies are
not even
twice as large. Some clever energy savings had to happen for this to occur.
Firing
neurons and manufacturing neurotransmitters, brains demand bigger hearts
and lungs to carry
the oxygen and nutrients for this work. There are brains four
to six times larger than ours
in elephants and the baleen whales, but at a price
of far larger bodies to support them.
How are we more efficient? Apparently, by
trading guts for brains--an interesting metaphor.
The most obvious savings lie in our rather small digestive tract, which is about
60 percent
smaller than in a similar-sized primate, just about balancing our
increased brain. It takes
a massive gut to digest raw plants and nuts. Eating
meat requires a simpler, smaller
digestive tract investment.
Higher quality digestion does not drive brain size, of course.
Pigs have rather
smaller stomachs, proportional to their weight, but evolution did not
favor
smarter pigs (though as mammals go they are not dumb); the investment went
elsewhere.
The same holds for birds and bats, who have the demands of flight to limit their
brain
sizes. All this suggests that something special about primates was at work
on us and the
chimps, who lie somewhere between us and the other primates in
brain/gut mass ratios.
There
are suggestive refinements to this basic engineering view. The big crunch
in brain energy
need comes in the first few years of life, precisely when our
maternal care is also so
vital. Mothers provide the extra energy babies need
through milk, and infants invest it in
their brains. This pattern of large
parental investment we have extended into longer and
longer periods of
dependency.
At a price. The birth canal diameter sets a severe limit on
head size at about
ten centimeters. We are born very immature, with flexible skulls. Some
babies
cannot even breathe on their own.
Some feel that these traits evolved around two
million years ago, with a switch
to a diet high in protein and fat, aided by tool use,
cooking, and eating lots
of meat. This is a positive feedback loop, driving the cognitive
side of brain
functions through the engineering constraint of energy for a given body mass.
We
found a social term in the feedback which made mothering essential over longer
times.
Of
course, there were other changes. Attaining an upright posture made it easier
to balance
that heavy brain on a spine, rather than hanging it at the end,
levered against gravity by
strong neck muscles, as four-footed beasts do. But
these engineering demands probably did
not drive our erect posture at first;
more likely, hands did.
Freeing our forepaws made
their development into hands for gripping, throwing,
and tool-making far easier. Some
evolutionists believe that as the African
plains dried out, stands of trees became farther
apart. Standing upright is a
faster way to cross the dangerous stretches of open country,
chimps do this
today, holding their arms over their heads for balance. Standing to run is
safer, too, because then they can see over tall grass.
The price was that babies had to be
held, because we were losing our pelts and
they could not hang on, as they had done in the
trees. (Actually, we may have
the same number of hairs as our ancestors, but ours are far
finer, and let air
flow to cool us. We keep some hair over most of our bodies, apparently
to alert
us to insects prowling on US.)
Thirty million years ago the African forest lay
unbroken and many large primates
lived in it. Today forests are spotty and only four large
species remain -- us,
chimps, gorillas, and orangutans. This suggests how profoundly
external changes
shaped us.
Neurophysiologist William Calvin believes that learning to use
our hands
orchestrated our growing brains into more and more complex movements --jabbing
with spears, say, and then throwing sharp rocks. (See his The Ascent of Mind.)
No other
animal has such suites of abilities, and Calvin suggests that this
drove our ability to
string guttural noises together so that they could carry
meaning: speech.
Continuity of
effort lies deep within us. We love the sense of flow in physical
movement enough to enjoy
sports, seeing in it a drama and significance far
beyond the objective importance of, say,
moving a pigskin around a field. We say
"He loves the sound of his own voice" as a mild
rebuke, ruefully admitting that
we share a love of extended expression, as well. (The
pleasure process does not
have to be strictly verbal, either, or else no one would write
books, or columns
like this one.)
There are signs of similar love for extended action in the
animal kingdom, as
when a hawk soars to great heights, sometimes riding thermals a mile
high in the
sky, without any apparent hunting motive.
Perhaps this ability to "throw long"
mentally is deeply implicated in our
evolutionary preference for bigger brains. Calvin and
others have argued that
the periodic ice ages, driving populations to and fro across
latitudes over the
last 2.5 million years, vitally forced selection for a brain-tool
connection.
Climate varying on all scales between decades and many millennia surely would
be
a persistent fitness filter.
There is another clue in nature to the big-brain issue.
Cetaceans--whales,
porpoises, and dolphins--also have large brain/body mass ratios. What
can we
learn from them? As biologist Lori Marino observed, "Fifty-five million years
ago, a
furry, hoofed mammal about the size of a dog ventured into the shallow
brackish remnant of
the Tethys Sea and set its descendants on a path that would
lead to their complete
abandonment of the land." They are a prize example of
mammalian adaptability, for though we
have quite recently spread over all the
Earth, into every clime, they ranged through the
oceans many tens of millions of
years ago.
Of course, aquatic animals have slight
appendages, and labor under different
engineering constraints. Still, the "encephalization
quotient" (this is
basically a ratio of the cerebral cortex volume to that of the
underlying brain
-- the higher the ratio, the smarter the creature. Let's call it EQ) of
the
cetaceans lies between ours and the other primates. There are several different
ways of
calculating EQs, and one useful method assigns us a value of 2.88, with
common chimps at
0.97. Between those lie the dolphins and porpoises, with values
ranging from 1.89 to 1.58.
These exceed the first hominids; we apparently
overtook the cetaceans in EQ around two
million years ago.
Perhaps the most important fact from fossil dolphin work is that the
cetaceans
attained their high levels about fifteen million years ago! By this measure,
they
have been fairly smart for a long time. Big brains are not, then, a trait
that keeps
driving to our high limit.
Together with our spurt of brain growth, trebling in two million
years, it seems
that the factors driving us upward in brain size (and presumably toward
better
brain organization as well) are unlike those which made the cetaceans bright. As
well,
our brains are organized quite differently, and parallels are hard to
find. This means the
cetaceans are a valuable, different case of evolution
upward in general intelligence.
There
is much disagreement about just how smart the cetaceans are, with factions
differing over
how to measure intelligence at all. But some sophisticated social
organization seems
clearly implied by their reliance upon complex song and
ability to solve a wide range of
problems, many requiring chains of inference
strikingly long.
There are other features in
our development that reveal deep similarities.
Evolution of big-brained cetaceans seems to
have occurred when the southern
oceans cooled and there was considerable biotic turnover.
This parallels our
conventional wisdom that hard times in African climes drove hominid
evolution.
Did porpoise brains level off in size once the oceans calmed down? Research is
not detailed enough to say, as yet.
Environment may have been a major player in dolphin
evolution, but so was social
evolution. The cetaceans' basic social grouping is the "pod,"
ranging in size
from a few to around forty. Interestingly, pod size scales up roughly with
EQ.
This resembles the primates, for whom mean group size also rises with EQ, from
one to a
hundred individuals. If group size measures social complexity, as seems
plausible, this
suggests a commonality between us and the cetaceans. They form a
telling boundary case by
which we may mark our uniqueness in nature.
No other placental mammal has as great a ratio
of brain size to body size as we
do, and we might be very near the design limit. Much
larger and our heads would
seriously endanger both mother and child while passing through
the birth canal.
It is a happy accident that this limit is enough to give us the room to
cogitate
on matters such as our own origins. If the limit had been, say, at a brain size
half our current average, we might be still the lords of creation, but we would
not reflect
upon that fact.
Of course, we are not just great thinkers; we are great, incessant talkers
as
well. Some evolutionary biologists think we may in part have grown big brains to
gossip,
stitching up our social fabric.
Evolution is a miserly opportunist. About ten million years
ago it worked upon
the primate ancestors we share with the chimpanzees, making small
adjustments in
existing parts to create advantageous change. We have much in common with
the
chimps.
We use the standard-issue mammalian hearing structures, which can resolve ten
sounds per second but no more, apparently because there were not a lot of clues
faster than
that in our world. Larynx, throat and mouth were engineered to
process food, perhaps then
retrofitted to process grunts, then words. Our upper
mouths and nasal passages can give us
sinus headaches, but they also lend our
voices a deep, resonant quality, like notes heard
from the ceiling sound chamber
of a concert hall. Such tones are rare in nature and
presumably proved useful.
Some evolutionists believe that early brain circuitry worked out
to control hand
movements got coopted into speech-making. How neurons built up to move
fingers
got retooled into circuits able to pull words from a dictionary and insert them
into
a flowing syntax is a tantalizing mystery.
Plainly the ten million years since we parted
genetic company with the chimps
have shaped us for speech, pointing to profound
evolutionary pressures. Since
the seventeenth century we have tried and failed to teach
chimps to talk. They
can artfully use sign language with vocabularies of around 500 words,
so the
neural circuitry is in place. Perhaps they used more sign language in the past
than
they do now, for their present capacity seems underemployed in the wild.
Our complicated
way of making speech is a Rube Goldberg kludge. Like most
animals, apes can swallow while
they breathe. We cannot, because our oblique
upper vocal boxes block our upper windpipe.
Our shorter jaws squeeze our wisdom
teeth, making them prone to impacting and rot. The
thinner jaw bone supports
smaller teeth, making chewing harder. All these disadvantages,
which could prove
fatal in adversity, were worth the gain of speech.
Still, chimps seem as
though they should be able to get out some smothered
phrases like our speech, if only their
brains were geared that way. But they
aren't, a clear sign of how our brain "hardware" and
"software" differ.
No animal but us can rap out quick strings of varied, precise noises,
syntactically arranged. There are monkeys who can hold fruit in their mouths,
peeling and
swallowing and spitting out pits at machine-gun speed. Competition
for scarce food and
poisonous pits explain why evolution would prize such
selection. Our mouths have simply
followed another path, one intricately wired
in with our minds.
This is part of a larger
problem we have in thinking about our link to animals.
We innately sense our connection to
nature, especially to those mammals close to
us: cats and dogs, horses and birds, our
collaborators. We recognize
intelligence in the stalking of a good hunting dog.
But talking?
We chattering primates set great stock in this recently developed
ability, of which
Neanderthal may have had only a smattering. Yet some mental
template for internal
symbol-arranging apparently goes back to that
ten-million-year juncture. Recent decades
have convinced chimpanzee researchers
that these nearest relatives have considerable
communication skills, managing
sign "languages" of many hundreds of words.
Ample signs of
this lie in the long saga of chimp communication. All primates
use sound to signal,
conveying alarm, status, comfort and delight; chimps even
laugh with an infectious mirth
that envelops the entire group. Even accents or
dialects may modulate their speech.
How
tempting, then, to see what else we have in common, particularly socially.
Can we
understand ourselves better by using the chimps as a mirror?
Just as humans differ among
themselves, chimps do -- and rather more profoundly.
The common chimp's short legs, long
arms and vastly more muscular body we
readily recognize. Few know that the species has
split, yielding the "pygmy"
chimp, the bonobo. (A beautiful introduction to them is Bonobo:
The Forgotten
Ape by Frans de Waal, with photographs by Frans Lanting.)
Science missed these
intriguing creatures, buried in central Africa's secluded
forests, until a discovery of a
skull in 1927, and live groups a few years
later.
Bonobos aren't actually pygmies; they
weigh only slightly less than the familiar
chimp, and stand up more than they do. This
gives them a strikingly more human
look, along with their slender legs and arms and smaller
head. Lounging and
moving about, they look uncannily like one of us, pleasantly at ease on
holiday.
Bonobo faces are darker, flatter, with bright red lips and no protruding
muzzles.
The central question of how distinctively we differ from the chimps depends on
which chimps
we mean. Humans, common chimps and bonobos have all evolved away
from our remote common
ancestor, each pursuing different strategies.
Consider the similarities: we share social
patterns like tribalism, and spend
our days alternately forming and splitting up groups to
accomplish varying tasks
("fissionfusion grouping"). Our females usually (though not
always) join the
family of the man when they mate; chimps have groups dominated by "alpha
males."
Infants are dependent for years, far longer than other species, staying close to
mothers who give birth at intervals of years. Many social patterns like grooming
and
cooperative gathering are remarkably alike. Chimps use simple tools, most
notably sticks to
draw termites from their mounds.
But the bonobos are egalitarian and peaceful, compared
with the common,
hierarchical chimps. Alpha males lord it over females in common chimpdom,
fighting each other for sexual privileges. Bonobos stick together more, spending
more time
at common tasks or just lounging.
Hierarchy is the essential glue of the common chimp; sex
does the job for
bonobos. While we humans have the largest genitalia of the primates, the
bonobos
get more action; they are the sexiest primate, by far. Much of their day passes
in a
sexual euphoria, with mutual masturbation and oral sex common among all
members of the
group.
Sex is the safety valve of bonobo society. Fights get settled finally not by
grooming
but by sex. Visitors use copulation as a calling card. They employ all
possible positions,
and unlike the common chimp, often have face-to-face sex.
Some primate scientists feel this
shows an emotional connection seen elsewhere
only in humans.
Animal comparisons have for
decades now been undercutting our arrogant
assertions of human uniqueness. We employ and
enjoy a particular primate
strategy, no more. Our 98 percent of genes shared with both
bonobo and common
chimps undoubtedly carries some programming for shared worldviews,
desires and
social certainties.
Chimps display advanced "cultural" traits. Some groups crack
nuts, while others
with the means at hand don't. Their social ladders are as precise and
well-tended as White House protocol. These imply a sense of self which bears up
under
clinical experiment. Chimps and other primates know who they are and their
place. Plainly
they think about matters we would recognize as substantial.
Indeed, a few million years
ago, we probably played quite similar conceptual
games.
We humans seem to stand somewhere
between the common chimps and the bonobos. We
like hierarchies, from armies to presidents
to movie stars, and sometimes will
even die for them. The common chimp wages war and
commits murder, apparently to
expand territory, just like us, though perhaps not as
frequently.
We humans use sexual cement, as do the bonobos. We pair off for long times,
unlike
the common chimp. But sex isn't our dominant organizing principle and
major recreation,
despite what advertisements might suggest.
Clearly we have evolved social strategies like
both types of chimp, with nuances
and powers they do not share. How much does this tell us
about ourselves?
Some primate researchers have begun to suspect that animal conduct codes
come
from strategies designed to make social living efficient, and not from some
innate
sense of evil.
This vision of morality as natural, derived as a design to shore up the
passing
on of genes, is a big conceptual leap. Such ideas disturb many of us, especially
those prone to elevating humans on a pedestal of lofty principles. That is why a
long-term
chimp observer in William Boyd's novel Brazzaville Beach gets angry
just seeing common
chimps grow violent in Tanzania's Gombe National Park. Though
supposedly a careful
scientist, trained to think rationally, he expects better
of chimps than of us, and
instantly responds to a woman primate specialist's
news with ironically chimp-hierarchical
rage. He wants chimps to be different,
better.
Many others do, too, when looking at
primates. Feminists might well embrace the
bonobos, who give females far more power,
promoting social cohesion. Whether any
of us would want humans to become sexual omnivores
is another matter. Most of us
seem to want our species to lose some of our blemishes,
especially aggression.
Generally among animals internal competition is mediated by social
rules --
crucially so among the primates, who have both intense societies and great
intelligence.
Rules get enforced among all primates by tit-for-tat game
strategy, with cheaters penalized
severely by ostracism.
Sociobiologists have grounded their theories of kinship selection to
explain why
animals will sacrifice themselves to better the common lot, since they share
genes that then get passed on.
High levels of cooperation in turn imply that primate
societies coordinate their
actions because they can predict outcomes, sometimes remarkably
distant in time.
Gathering strategies among baboons show memory over days. This is not
unique to
primates, of course; canines hunt in groups and share the kill, and insects are
geniuses of unthinking cooperation.
But primate social systems are more advanced and
nuanced than others'. This
suggests a long evolutionary history of what we can only term
morality. Such
development might well apply to any social beings, even aliens or machine
societies.
This idea strikes solidly against much prevailing moral philosophy, which tends
toward top-down principles that dictate behavior, following logically. Our
current model
invokes images like Moses bringing down ten commandments. We speak
of moral law, not moral
efficiency.
Behavioral studies among primates reveal a bottom-up origin for morals and
ethics.
Getting along and working in concert would shore up the survival of
groups which adopted
such shared rules. Chimps, and probably our distant hominid
ancestors, lived in tribes of
one or two hundred souls. Tribes that enforced
social rules probably fared better in the
competition for food and territory.
They did not waste energy and time on internal
friction. Building a bias toward
such rules into the genome would cement this social
invention.
This is not group selection in the old genetic sense, for still it is up to
individuals
to pass on genes. But it does place all social evolution in a
continuum, with us as merely
the latest outstanding example.
This larger biological context for ourselves does not mean
that humans are
merely animals, but that animals are rather more than we have thought. Many
will
find even this adjustment hard to take.
If right and wrong emerge from social evolution
to promote survival, then they
are merely utilitarian. Worse, our current ideas of right
and wrong have no
particular cachet, for they are simply the latest fine-tuned ideas with
which we
navigate on the strange seas of our quite recent civilization.
Many people, and
probably particularly humanists of the "social constructionist"
persuasion, will dislike
this entire line of reasoning. Its foundation in solid
anthropological field work will not
matter; it implies a definition of being
human that seemingly mocks our dignity, our
Renaissance centrality.
Let us take the logic a step further. Unease at such descriptions
may itself
have a natural origin. In the last six million years we have been accelerated by
evolutionary forces we can still only vaguely sense. Wandering the plains of
Africa, we may
have developed a need to see ourselves as quite distinct from all
other life -- higher,
better.
This could make our use of other species untroubling. Far easier to slaughter
large
numbers of game animals by driving them off cliffs or into pits, as our
ancestors did, if
we can detach ourselves from their death throes. Our sense of
our specialness itself might
have been selected for at the social level among
hominid tribes far in the past.
This
ability of evolutionary ideas to trump even the moral misgivings of the
humanists is bound
to cause even more discomfort. It is a final recta-argument
for our profound
non-specialness.
Though we are special: the last surviving hominids. We have occupied the
smart
niche with no rivals since the Neanderthals vanished 35,000 years ago. Until
then,
there was always at least one competitor primate of intelligence roughly
within our range.
We might also expect smart aliens to be alone. Perhaps the shadow across these
last 35,000
years has been a vague sense of existential loneliness, with no one
to talk to, even with
sign language. SETI and our experiments with dolphin and
chimp communication may show this
shadowy sense.
As for SETI, perhaps crafty intelligence such as ours truly is rare. After
all,
we seem much smarter than our environment demands. Maybe we are smart mostly
because we
are so social -- interactively so, not as a mere herd.
Aliens might be equally social,
then, which is good news for SETI --they'll want
to talk. They might well have a deep moral
sense, too, for the reasons I've
sketched. That may make it easier to communicate truly
difficult, cultural
matters.
But their morality would be good for them, not necessarily us.
Chimps make war
on rival bands, just as we do. Aliens might have a history of war and a
visceral
dislike of outsiders, just like us. In their science fiction movies, loathsome
hairless
primates descend from fierce ships, slicing the peace-loving arachnids
with their death
rays....
Aliens who truly despise and fear other species might have overrun and destroyed
their biosphere (as we seem in some danger of doing). We won't hear from them in
the radio
frequencies, luckily, for they will probably be impoverished.
SETI might detect smart
aliens who cooperate with each other readily (avoiding
insect-hive sociology, though, which
seems unlikely to produce high
intelligence). If they have less fear of others, and want to
gossip, they might
well put out the radio welcome mat -- a bright beacon.
This suggests that
we look for the spectacularly successful aliens who might
broadcast strong beacon
signals--the rich guys. Just as we have come to dominate
our planet in an evolutionary
instant, something similar may happen on the scale
of whole solar systems, elsewhere. Only
such a civilization could master the
enormous resources to build big beacons.
If so, a
strategy of looking toward our galactic center may be best. Not only is
the center the one
obvious symmetric point in the galaxy, it also lies in the
richest, highest density of
stars.
Stellar evolution began there and moved outward, stars forming first at the
dense
central bulge. Our comfortable, suburban region, 2/3 of the way out into
the disk, produced
the metal-rich planets hospitable to life later than did the
stars nearer the core.
Instead
of searching nearby stars, maybe we should look more deeply, and inward.
It is 9.8,000
light years to the galactic center. There evolution has had nearly
ten billion years to
work. It might need that much time, to arrive at many such
smart rarities as ourselves.
Comments
and objections to this column are welcome. Please send them to Gregory
Benford, Physics
Department, Univ. Calif., Irvine, CA 92717, or benford@uci.edu.