Comparative, Evolutionary & Developmental Psychology. News, articles and media from the world of human and non-human behaviour, development and cognition.
Saturday, 1 December 2012
Saturday, 3 November 2012
Asian Elephant Learns To Talk Korean
(CNN.com, 2, Nov 2012) - Korean is considered one of the hardest
languages in the world to master, but an elephant in a South Korean zoo is
making a good start.
Journal article: http://www.cell.com/current-biology/retrieve/pii/S096098221201086X
Journal article: http://www.cell.com/current-biology/retrieve/pii/S096098221201086X
Koshik, a 22-year-old Asian elephant has stunned experts and
his keepers at Everland Zoo near Seoul by imitating human speech. Koshik can
say the Korean words for "hello," "sit down,"
"no," "lie down" and "good." His trainer, Kim
Jong Gap, first started to realize Koshik was mimicking him several years ago.
"In 2004 and 2005, Kim didn't even know that the
human voice he heard at the zoo was actually from Koshik," zoo spokesman
In Kim In Cherl said. "But in 2006, he started to realize that Koshik had
been imitating his voice and mentioned it to his boss."
His boss initially called him "crazy."
Koshik's remarkable antics grabbed the interest of an
elephant vocalization expert thousands of kilometers away at the University of
Vienna in Austria.
""There was a YouTube video about Koshik
vocalizing, and I was not sure if it was a fake, or if it was real," Dr.
Angela Stoeger-Horwath said. She traveled with fellow expert Dr. Daniel
Mietchen to South Korea in 2010 to test the elephant's ability.
They recorded Koshik repeating certain words his keeper said and then played them for native Korean speakers to see, if they were recognizable.
They recorded Koshik repeating certain words his keeper said and then played them for native Korean speakers to see, if they were recognizable.
"It is, for some of the sounds he makes, quite
astonishing for how similar they are," said Mietchen of the University of
Jena in Germany. "For instance the word 'choa' (meaning good) -- if you
hear it right after what the keeper says -- it's quite similar."
The findings have been published in the journal Current
Biology this week and describe how Koshik places the tip of his trunk into his
mouth to produce his convincing impression of a human voice.
Koshik was born in captivity in 1990 and was transferred to
Everland Zoo a few years later. From the age of 5 to 12 there were no other
elephants with Koshik at the zoo, and his only interaction was with humans. The
researchers believe Koshik may have learned certain words out of necessity
"to cement social bonds."
Koshik is expected to draw quite a crowd when the public sees him in the spring after construction at the zoo is completed.
Tuesday, 23 October 2012
Big Brain Power Demands Fire Power!
"Mmm yummy, tasty, juicy...puh puh puh!" |
(Wired.com, 23, Oct 2012) - Eating a raw food diet is a
recipe for disaster if you’re trying to boost your species’ brainpower. That’s
because humans would have to spend more than 9 hours a day eating to get enough
energy from unprocessed raw food alone to support our large brains, according
to a new study that calculates the energetic costs of growing a bigger brain or
body in primates. But our ancestors managed to get enough energy to grow brains
that have three times as many neurons as those in apes such as gorillas,
chimpanzees, and orangutans. How did they do it? They got cooking, according to
a study published online today in the Proceedings of the National Academy of
Sciences.
“If you eat only raw food, there are not enough hours in the
day to get enough calories to build such a large brain,” says Suzana
Herculano-Houzel, a neuroscientist at the Federal University of Rio de Janeiro
in Brazil who is co-author of the report. “We can afford more neurons, thanks
to cooking.”
Humans have more brain neurons than any other primate — about
86 billion, on average, compared with about 33 billion neurons in gorillas and
28 billion in chimpanzees. While these extra neurons endow us with many
benefits, they come at a price — our brains consume 20 percent of our body’s
energy when resting, compared with 9 percent in other primates. So a
long-standing riddle has been where did our ancestors get that extra energy to
expand their minds as they evolved from animals with brains and bodies the size
of chimpanzees?
One answer came in the late 1990s when Harvard University
primatologist Richard Wrangham proposed that the brain began to expand rapidly
1.6 million to 1.8 million years ago in our ancestor, Homo erectus, because
this early human learned how to roast meat and tuberous root vegetables over a
fire. Cooking, Wrangham argued, effectively predigested the food, making it
easier and more efficient for our guts to absorb calories more rapidly. Since
then, he and his colleagues have shown in lab studies of rodents and pythons
that these animals grow up bigger and faster when they eat cooked meat instead
of raw meat — and that it takes less energy to digest cooked meat than raw
meat.
In a new test of this cooking hypothesis, Herculano-Houzel
and her graduate student, Karina Fonseca-Azevedo, now a neuroscientist at the
National Institute of Translational Neuroscience in São Paulo, Brazil, decided
to see if a diet of raw food inherently put limits on how large a primate’s
brain or body could grow. First, they counted the number of neurons in the
brains of 13 species of primates (and more than 30 species of mammals). The
researchers found two things: one, that brain size is directly linked to the
number of neurons in a brain; and two, that that the number of neurons is
directly correlated to the amount of energy (or calories) needed to feed a
brain.
After adjusting for body mass, they calculated how many
hours per day it would take for various primates to eat enough calories of raw
food to fuel their brains. They found that it would take 8.8 hours for
gorillas; 7.8 hours for orangutans; 7.3 hours for chimps; and 9.3 hours for our
species, H. sapiens.
These numbers show that there is an upper limit on how much
energy primates can get from an unprocessed raw diet, Herculano-Houzel says. An
ape’s diet in the wild differs from a modern “raw food diet,” in which humans
get sufficient calories from processing raw food in blenders and adding protein
and other nutrients. In the wild, other apes can’t evolve bigger brains unless
they reduce their body sizes because they can’t get past the limit of how many
calories they can consume in 7 hours to 8 hours of feeding per day. But humans,
she says, got around that limit by cooking. “The reason we have more neurons
than any other animal alive is that cooking allowed this qualitative change —
this step increase in brain size,” she says. “By cooking, we managed to
circumvent the limitation of how much we can eat in a day.”
This study shows “that an ape could not achieve a brain as
big as in recent humans while maintaining a typical ape diet,” Wrangham says.
Paleoanthropologist Robert Martin of The Field Museum in
Chicago, Illinois, agrees that the new paper does “provide the first evidence
that metabolic limitations” from a raw food diet impose a limit on how big a
primate’s brain — or body — can grow. “This could account for small brain sizes
of great apes despite their large body sizes.” But “the jury is still out” on
whether cooking was responsible for the first dramatic burst of brain growth in
our lineage, in H. erectus, Martin says, or whether our ancestors began cooking
over a fire later, when the brain went through a second major growth spurt
about 600,000 years ago. Hearths show up in the archaeological record 800,000
years ago and the regular use of fire for cooking doesn’t become widespread
until more recently.
But to Herculano-Houzel’s mind, our brains would still be
the size of an ape’s if H. erectus hadn’t played with fire: “Gorillas are stuck
with this limitation of how much they can eat in a day; orangutans are stuck
there; H. erectus would be stuck there if they had not invented cooking,” she
says. “The more I think about it, the more I bow to my kitchen. It’s the reason
we are here.”
Monday, 22 October 2012
NOC, the white whale that tried to sound like a humanz
RE: Audio file. I bet his has names for all his toes |
(Discover Magazine.com, 22, Oct 2012) - Listen to this recording. It sounds like a drunkard playing
a kazoo, but it’s actually the call of a beluga (a white whale) called NOC.
Belugas don’t normally sound like that; instead, NOC’s handlers think that his
bizarre sounds were an attempt at mimicking the sounds of human speech.
The idea isn’t far-fetched. Belugas are so vocal that
they’re often called “sea canaries”. William Schevill and Barbara Lawrence –
the first scientists to study beluga sounds in the wild – wrote that the calls
would occasionally “suggest a crowd of children shouting in the distance”. Ever
since, there have been many anecdotes that these animals could mimic human
voices, including claims that Lagosi, a male beluga at Vancouver Aquarium,
could speak his own name. But until now, no one had done the key experiment. No
one had recorded a beluga doing its alleged human impression, and analysed the
call’s acoustic features.
NOC provided the right opportunity. He was one of three belugas that arrived at the National Marine Mammal Foundation (NMMF) in San Diego in August 1977, after originally being captured by Inuit hunters in Canada. Being the smallest of the trio, NOC was cheekily named after “noseum”, the tiny gnats that plague the hunters during the Canadian summer.
In May 1984, seven years after NOC’s arrival at San Diego,
the staff at the NMMF started making noises that resembled speech-like sounds.
At first, no one could work out where the noises were coming from. They sounded
“as if two people were conversing in the distance just out of range for our
understanding,” writes Sam Ridgway.
The mystery was solved later that year, through a lucky
accident. A group of divers were training outside NOC’s enclosure, when one of
them surfaced and asked “Who told me to get out?”
It was NOC.
After that incident, the trainers watched him more closely
and confirmed that he was the source of their mysterious noises. He did so
spontaneously, without any training. And he made the calls when alone or when
his human handlers were around, and never when socialising with the other two
whales in his tank.
Ridgway’s team recorded NOC’s calls, and found that their
acoustic features were very unlike typical whale sounds, but not unlike those
of human speech. The rhythm was comparable, with vocal bursts that lasted for
around three seconds and gaps of less than 0.5 seconds. NOC’s calls had a
fundamental frequency of 200 to 300 Hz (the octave around middle C), which is
similar to the range of human speech, and much lower than a whale’s usual
sounds.
After many rounds of recording, Ridgway’s team started
training NOC to make the speech-like sounds on cue, so they could better study
how he did it. Whales produce sounds by sending air from their nasal tract past
their phonic lips – a pair of vibrating muscular folds that act like our voice
box. From there, the air enters two pouches called the vestibular sacs. NOC
mimicked human noises by increasing the pressure in his nasal tract, finely
controlling the vibrations of his phonic lips, and greatly over-inflating his
vestibular sacs, to hit those lower registers.
Stan Kuczaj, who studies sea mammal behaviour at the
University of Southern Mississippi, is convinced. “The beluga did seem to be
mimicking human speech, and did so quite successfully,” he says. “Belugas are
known to have excellent acoustic mimicry skills.”
Justin Gregg from the Dolphin Communication Project, says,
“Listening to the recording, it does not sound exactly like human speech—I have
no idea what the whale is “saying”—but [Ridgway’s team] have certainly made the
case that the whale was trying very hard to produce human language sounds.”
“We do not claim that our whale was a good mimic compared to
such well-known mimics as parrots or mynah birds,” writes Ridgway. But he
maintains that the calls he recorded are a good example of vocal learning –
where animals learn to make noises based on hearing others around them. In this
case, it’s likely that NOC picked up the pitch and rhythm of human speech after
spending years in close contact with his handlers.
Why? Kuczak says, “I don’t think the whale was trying to
learn human speech in order to communicate with humans.” Instead, he suggests
that NOC was simply interested in these odd sounds in his environment, and
tried to reproduce them.
Gregg adds that belugas, like dolphins, are very social
animals, and the ability to learn and mimic new calls might help them to
address other individuals. They also have very sophisticated echolocation, and
can subtly alter their ultrasonic clicks to scan their environment. “They
already have an amazing ability to alter parameters of their vocal tract, which
should make it all the more easy to replicate human speech sounds,” says Gregg.
NOC’s attempts at human-like sounds continued for four
years. As he grew up, he stopped, but he carried on being talkative, with a
regular portfolio of “squawks, rasps, yelps or barks”.
Five years ago, NOC stopped calling altogether. He finally
passed away after 30 years at the NMMF. Through Ridgway’s recordings, his voice
echoes on.
Journal article: http://www.cell.com/current-biology/abstract/S0960-9822(12)01009-3
Friday, 19 October 2012
Books Change How a Child’s Brain Grows (Zombie community pleased)
Image: Peter Dedina/Flickr "I loveses you book, I'll never replace you in the near future with an electronic alternative" |
(Wired.com, 18, Oct 2012) - Books and educational toys can
make a child smarter, but they also influence how the brain grows, according to
new research presented here on Sunday at the annual meeting of the Society for
Neuroscience. The findings point to a “sensitive period” early in life during
which the developing brain is strongly influenced by environmental factors.
Studies comparing identical and nonidentical twins show that
genes play an important role in the development of the cerebral cortex, the
thin, folded structure that supports higher mental functions. But less is known
about how early life experiences influence how the cortex grows.
To investigate, neuroscientist Martha Farah of the
University of Pennsylvania and her colleagues recruited 64 children from a
low-income background and followed them from birth through to late adolescence.
They visited the children’s homes at 4 and 8 years of age to evaluate their
environment, noting factors such as the number of books and educational toys in
their houses, and how much warmth and support they received from their parents.
More than 10 years after the second home visit, the
researchers used MRI to obtain detailed images of the participants’ brains.
They found that the level of mental stimulation a child receives in the home at
age 4 predicted the thickness of two regions of the cortex in late adolescence,
such that more stimulation was associated with a thinner cortex. One region,
the lateral inferior temporal gyrus, is involved in complex visual skills such
as word recognition.
Home environment at age 8 had a smaller impact on
development of these brain regions, whereas other factors, such as the mother’s
intelligence and the degree and quality of her care, had no such effect.
Previous work has shown that adverse experiences, such as
childhood neglect, abuse, and poverty, can stunt the growth of the brain. The
new findings highlight the sensitivity of the growing brain to environmental
factors, Farah says, and provide strong evidence that subtle variations in
early life experience can affect the brain throughout life.
As the brain develops, it produces more synapses, or
neuronal connections, than are needed, she explains. Underused connections are
later eliminated, and this elimination process, called synaptic pruning, is
highly dependent upon experience. The findings suggest that mental stimulation
in early life increases the extent to which synaptic pruning occurs in the
lateral temporal lobe. Synaptic pruning reduces the volume of tissue in the
cortex. This makes the cortex thinner, but it also makes information processing
more efficient.
“This is a first look at how nurture influences brain
structure later in life,” Farah reported at the meeting. “As with all
observational studies, we can’t really speak about causality, but it seems
likely that cognitive stimulation experienced early in life led to changes in
cortical thickness.”
She adds, however, that the research is still in its
infancy, and that more work is needed to gain a better understanding of exactly
how early life experiences impact brain structure and function.
The findings add to the growing body of evidence that early
life is a period of “extreme vulnerability,” says psychiatrist Jay Giedd, head
of the brain imaging unit in the Child Psychiatry Branch at the National
Institute of Mental Health in Bethesda, Maryland. But early life, he says, also
offers a window of opportunity during which the effects of adversity can be
offset. Parents can help young children develop their cognitive skills by
providing a stimulating environment.
Wednesday, 17 October 2012
"Sponging" dolphins pass fishing trick from mother to daughter
*Muffled* Can someone CLICK! get this CLICK! off my CLICKIN! nose!? |
(Reuters.con, 15, Oct 2012) - A small population of dolphins
in Western Australia state not only use sponges to help catch fish but the rare
hunting technique has been passed from mother to daughter for generations,
Australian researchers said.
Sightings of dolphins carrying sponges on their snouts to
protect their sensitive noses while dislodging fish and crustaceans from the
rocky ocean floor has been recorded since the 1980s.
But researchers at the University of New South Wales added a
new dimension to their research by using computer modeling of behavior (Social Network Analysis) and
genetics to estimate how long the technique, which they call "sponging",
has gone on.
"What's unique about the sponging behavior is that only
about five percent of dolphins use the sponges as a tool, and it's only one
maternal line," said Anna Kopps at the University of New South Wales Evolution
Ecologist Research Centre.
"What's new about this study now is we've got the time
perspective," she told Reuters.
Scientists believe one single female started sponging in
Shark Bay, Western Australia, and all her descendants in that area learned the
behavior from their mothers.
Knowing this, and that the sponging was done 30 years ago, computer
modeling allowed them to study the spread of the behavior over the past three
decades -- and then reverse the process using genetics and behavior to figure
out when it might have begun.
Ultimately, they estimated that sponging has been going on
for some 180 years, or roughly eight generations of dolphins.
"It's interesting that the behavior doesn't spread to
the entire population and it doesn't go extinct either," said Kopps.
Dolphin offspring are dependent on their mothers for about
four years, giving them ample time to observe and learn survival techniques.
The maximum lifespan of a dolphin is about 40 years.
"We don't know if it's teaching or other forms of
learning," Kopps said.
While male dolphins also learn sponging from their mothers,
the study found they don't pass the technique on.
"Some males use it but not many and it will be a dead
end because they don't learn from the dads," Kopps said.
Tuesday, 16 October 2012
Neanderthals ... They're Just Like Us?
Photograph by Joe McNally, National Geographic "Come at me bro" |
(National Geographic.com, 12, Oct 2012) - Well, not exactly. But new discoveries have had a
surprisingly humanizing effect.
The Neanderthals are both the most familiar and the least understood
of all our fossil kin.
For decades after the initial discovery of their bones in a
cave in Germany in 1856 Homo neanderthalensis was viewed as a hairy brute who
stumbled around Ice Age Eurasia on bent knees, eventually to be replaced by
elegant, upright Cro-Magnon, the true ancestor of modern Europeans.
Science has long since killed off the notion of that witless
caveman, but Neanderthals have still been regarded as quintessential losers—a
large-brained, well-adapted species of human that went extinct nevertheless,
yielding the Eurasian continent to anatomically modern humans, who began to
migrate out of Africa some 60,000 years ago.
Lately, the relationship between Neanderthals and modern humans
has gotten spicier.
According to a new study that analysed traces of Neanderthal
DNA in present-day humans, Neanderthals may have been interbreeding with some
of the ancestors of modern Eurasians as recently as 37,000 years ago. And
another recent study found that Asian and South American people possess an even
greater percentage of Neanderthal genes.
"These are complexities in the out-of-Africa story that
certainly I would not have anticipated two or three years ago," said Chris
Stringer, a paleoanthropologist at the Natural History Museum in London and
author of Lone Survivors: How We Came to Be the Only Humans on Earth.
In their original incarnation, Neanderthals were viewed as
the primitive, backward cave dwellers of Eurasia, far less complex than the
sophisticated Homo sapiens who used language and developed sophisticated art as
they migrated out of Africa and conquered the world.
But new studies are making it much harder to draw a clean
line between us and them.
"It's increasingly difficult to point to any one thing
that Neanderthals did and Homo sapiens didn't do and vice versa," said
John Shea, an archaeologist at Stony Brook University in New York.
"These Ice Age people, both Neanderthals and Homo
sapiens, survived, thrived, and increased their numbers under conditions that
would probably kill people nowadays, even ones that are equipped with modern
survival technology."
The draft sequence of the Neanderthal genome, published in
the journal Science in 2010, provided the first compelling genetic evidence
that Neanderthals and H. sapiens had more in common than just an ancestor in
Africa hundreds of thousands of years ago.
The researchers, under the direction of Svante Pääbo of the
Max Planck Institute for Evolutionary Anthropology, found that 2.5 percent of
the genome of an average human living outside Africa today is made up of
Neanderthal DNA. The average modern African has none.
This suggested that some interbreeding had taken place
between the two kinds of human, probably in the Middle East, where the early
modern humans migrating out of Africa would have encountered Neanderthals
already living there.
The even larger percentage of Neanderthal DNA found in
Asians and South Americans, announced in Science in August, could indicate
additional interbreeding in Asia long ago, or could mean that the percentage of
Neanderthal DNA in Europeans was diluted by later encounters.
Not everyone is convinced that interbreeding was responsible
for similarities in the Neanderthal and H. sapiens genomes. "The
similarities they're seeing may be ancient," Shea noted.
Another recent study, published in the journal Proceedings
of the National Academy of Sciences in August, calculated that the shared DNA
could have come from an earlier, common ancestor of Neanderthals and H.
sapiens—no hanky-panky necessary.
A new study by Pääbo's team, published last week in PLOS
Genetics, also considered the possibility that the presence of Neanderthal DNA
in people living outside Africa today could be traced far back, to the common
ancestor of both Neanderthals and modern humans in Africa.
Perhaps the early modern humans who left Africa 60,000 years
ago were already genetically more similar to the Neanderthals—who had left
hundreds of thousands of years before—than were the modern human populations
that stayed behind in Africa. In that case, no interbreeding would have needed
to occur to account for the trace of Neanderthal DNA in non-Africans today.
To test the two hypotheses, Pääbo's group analyzed the
lengths of segments of Neanderthal DNA in modern Europeans to determine when
Neanderthal genes may have mixed with those of modern humans. The date they came
up with for the gene flow was 37,000 to 86,000 years ago, and most likely
47,000 to 65,000 years ago.
This date strongly suggests there was indeed interbreeding
between "us and them," when H. sapiens was moving into the Middle
East from Africa and would have encountered populations of Neanderthals already
settled there.
"This [interbreeding] could have been a really powerful
mechanism for humans to adapt as they moved into Eurasia," said Sriram
Sankararaman, a statistical geneticist at Harvard Medical School and the lead
author of the PLOS Genetics study.
Another group, publishing last year in Science, for example,
determined that modern humans gained from Neanderthals a family of genes that
helps the immune system fight off viruses. Breeding with the locals could have
unwittingly given H. sapiens a survival advantage in a new land.
"[Neanderthals] are not just some extinct group of
related hominids," Pääbo said. "They are partially ancestors to
people who live today."
Take any two unrelated humans today, Pääbo noted, and
they'll differ in millions of places in their genetic code. But the Neanderthal
genome varies on average from that of H. sapiens in only about a hundred
thousand positions. Pääbo and his colleagues are now trying to figure out the consequences
of those differences.
Regardless of the similarities to our DNA, how
"human" were Neanderthals in their sensibilities?
Last month a study led by the Gibraltar Museum and published
in PLOS ONE documented a multitude of fossil remains of bird wings,
particularly from big black raptors, at Neanderthal sites in southern Europe.
The team suggested that Neanderthals could have been plucking feathers from the
wings for personal use or even for ritual ornaments.
"We have other evidence for Neanderthals preferring
mineral pigments that are dark, blackish color," Stony Brook's Shea said.
"There may be something for them with the color black just as there seems
to be something for us with the colour red."
Sophisticated art, however, still appears to remain in the
realm of H. sapiens.
The ancestors of modern humans left behind images of animals
and other objects in caves around the world, most famously at Lascaux cave and
Chauvet Cave (pictures) in southern France. Paintings in the latter cave could
be as ancient as 37,000 years old. (See a prehistoric time line.)
Images found in a cave called El Castillo on the Spanish
coast were recently dated at more than 40,800 years old: a time before
Neanderthals disappeared, raising the tantalizing possibility that they were
indeed the artists. However, "it hasn't been demonstrated that
Neanderthals produced any of that cave art," the Natural History Museum's
Stringer said.
The simpler answer is that H. sapiens, who had also reached
Europe by that time and are known to have produced later but similar art, were
responsible.
Neanderthals, though, have proven advanced in other ways.
They used pigments and may have made jewellery; some made
complex tools. "We know they buried their dead," Stringer said. In
2010, researchers from the Smithsonian Institution even found evidence that the
Neanderthal diet included a diverse mixture of plants, and that they cooked
some of the grains.
"Cooking something like oatmeal is not what we would
have imagined," said John Hawks, paleoanthropologist at the University of
Wisconsin-Madison. With no pots, Neanderthals may have cooked inside leaves,
Hawks suggested. "That starts to sound like cuisine."
"Neanderthals have gone from being different from us to
being like us," Hawks noted. "They're looking like [Homo sapiens]
hunter-gatherers look."
But while modern humans continued to develop cultural
complexity and spread across the globe, the Neanderthals vanished. Why remains
a mystery.
Are Humans Monogamous or Polygamous?
Photo by Georges Gobet/AFP/Getty Images. "My eyes are up here pal" |
(Slate.com, 9, Oct 2012) - Archaeologists, anthropologists, and biologists agree: It’s complicated.
What makes us different from all the other animals? Is it
our swollen brains, our idle hands, or perhaps our limber thumbs? In 2011, a
research team reviewed the quirks of human DNA and came across another oddly
shaped appendage that makes us who we are: I mean, of course, man's smooth and
spineless member. The penises of lots of mammals are endowed with "horny
papillae," hardened bumps or spikes that sometimes look like rows of studs
on a fancy condom. These papillae enhance sensation, or so it has been claimed,
and shorten a mating male's delay to climax. Since humans lost their phallic
bumps several million years ago, it could be that we evolved to take it slow.
And it could also be the case that longer-lasting sex produced more intimate
relationships.
So (one might argue that) the shedding of our penis spines
gave rise to love and marriage, and (one could also say that) our tendency to
mate in pairs pushed aside the need for macho competition, which in turn gave
us the chance to live together in large and peaceful groups. Life in groups has
surely had its perks, not least of which is that it led to bigger brains and a
faculty for language, and perhaps a bunch of traits that served to civilize and
tame us. And so we've gone from horny papillae to faithful partners—from
polygamy to monogamous humanity.
I like this story well enough, but it may or may not be
true. In fact, not all penis spines in nature serve to quicken sex—orangutans
have fancy ones but waste a quarter of an hour in the act—so we don't know what
to make of our papillae or the lack thereof. That won't stop anyone from
wondering.
Since we like to think that how we mate defines us, the sex
lives of ancient hominids have for many years been examined in computer
simulations, by measuring the circumferences of ancient bones, and by applying
the rules of evolution and economics. But to understand the contentious field
of paleo-sexology, one must first address the question of how we mate today,
and how we’ve mated in the recent past.
According to anthropologists, only 1 in 6 societies enforces
monogamy as a rule. There's evidence of one-man-one-woman institutions as far
back as Hammurabi's Code; it seems the practice was further codified in ancient
Greece and Rome. But even then, the human commitment to fidelity had its
limits: Formal concubines were frowned upon, but slaves of either sex were fair
game for extramarital affairs. The historian Walter Scheidel describes this
Greco-Roman practice as polygynous monogamy—a kind of halfsy moral stance on
promiscuity. Today's Judeo-Christian culture has not shed this propensity to
cheat. (If there weren't any hanky-panky, we wouldn't need the seventh
commandment.)
In The Myth of Monogamy, evolutionary psychologists David P.
Barash and Judith Eve Lipton say we're not the only pair-bonding species that
likes to sleep around. Even among the animals that have long been known as
faithful types—nesting birds, etc.—not too many stay exclusive. Most dally.
"There are a few species that are monogamous," says Barash. "The
fat-tailed dwarf lemur. The Malagasy giant jumping rat. You've got to look in
the nooks and crannies to find them, though." Like so many other animals,
human beings aren't really that monogamous. Better to say, we're monogamish.
That –ish has caused no end of trouble, for lovers and for
scientists. Efforts to define our sexual behavior often run afoul of humans’
in-between-ness. Take one common proxy measure of how a primate species
copulates: testis size. A male that's forced to share its partners might do
well to make each ejaculation count by firing off as many sperm as possible.
Chimpanzees mate rather freely and show a high degree of male-male competition.
They also have giant balls, for blowing away their rivals'. Gorillas, on the
other hand, have their sexual dynamics more worked out: The alpha male has all
the sex; the other males are screwed. Since there's less chance of going
head-to-head on ejaculations, tesis size isn't so important. Gorilla balls are
pretty small. And what about a man's testes? They're not so big and not so
little. They're just eh.
Male gorillas may not one-up each other with their testes,
but they do rely on other traits to get and keep their harems. That's why male
gorillas are so huge and fearsome: so they can fight off other males for social
dominance. Within a species, the difference between the male and female body
type yields another proxy for mating habits: The bigger the gap in body size,
the more competitive the males, and the greater the inclination toward
polygynous arrangements. So how does the split between human men and women
compare to that of other primates? We're sort of in the middle.
Seeing as we're neither one thing nor the other, scientists
have been left to speculate on how our ancestors might have done their thing.
Were they like gorillas, where most males suffered while one dude enjoyed the
chance to spread his seed? Or more like chimpanzees—sleeping around, with males
competing for multiple partners? Or is there another possibility, like the one
championed by Christopher Ryan and Cacilda Jethá in their best-selling and
soundly criticized paean to free love, Sex at Dawn? According to that book's
authors, our ancestors did as bonobos do: They had rampant sex without much
bickering.
Such discussions tend to dead-end quickly, though, since we
just don't know for sure. Our most recent relatives in common with these other
primates lived about 6 million years ago. (I suppose if bonobos could be
anthropologists, one of them might write a book on whether bonobo sexuality
evolved from something humanlike.) "What this really is," says
Barash, "is a Rorschach test for the people asking the question."
We do have data on human mating trends, but the record tends
to be a little spotty. In 2010, a team in Montreal completed its analysis of
breeding ratios for Homo sapiens based on a careful study of DNA. By measuring
diversity in the human chromosomes, the researchers tried to figure out what
proportion of the breeding pool has been composed of females. They found a
ratio of slightly more than one-to-one, meaning that there were at least 11
ladies for every minyan of procreating men. But the math they used turned out
to be a little wonky, and after making some corrections, they revised the
numbers up a bit toward a ratio of 2. These estimates, they wrote, are still
within the range you'd find for societies described as "monogamous or
serially monogamous, although they also overlap with those characterizing
polygyny." Once again—we're monogamish.
At what point in hominid evolution did this in-between
behavior appear? Paleontologist Owen Lovejoy published fossil specimens in 2009
from Ardipithecus ramidus, which lived 4.4 million years ago. He used the newly
described species as evidence for the hominids' great transition to (mostly)
one-on-one relationships. Ardi walked on two legs, which freed its hands for
carrying food, and males that carried food, he says, were thus enabled to take
that food to females. They'd evolved a way to pitch woo and bring home the
bacon. By this stage in evolution, sexual dimorphism had been diminished, too,
and so had other signs of male-on-male competition. Taken together, Lovejoy
wrote in Science, these data points suggest "a major shift in life-history
strategy [that] transformed the social structure of early hominids." Males
and females had started pairing off, and dads learned how to support their
families.
A computation-minded researcher at the University of
Tennessee, Sergey Gavrilets, finished up a study in May of how that transition
might have followed the laws of natural selection. It's not an easy puzzle.
Gavrilets explains that a polygynous mating scheme can lead to a "vicious
circle" where males waste their time and energy in fighting over females.
The group might be better off if everyone split off into happy, hetero-pairs
and worked on caring for their babies. But once you've started wars for sex,
there's an evolutionary push to keep them going. So Gavrilets set up a computer
model to see if any movement toward monogamy might conform to what we know of
evolution. He found that a shift in female preference for mates that offer food
and child care could have made it happen. (Low-ranked males might also favour relationships with partners that didn't cheat.)
Gavrilets says he needs to check his model against a few
more theories of how human-style partnerships evolved—including one that
involves the invention of cooked food. But he's made the case, at least, that
biology could lead to modern love, without any help from law or custom.
"Culture came much later," he told a reporter in the spring,
"and only augmented things that were already in place."
That's one idea, but the study of monogamy takes all kinds.
Others have been more interested in the culture and the customs. In January, a
scholar named Joe Henrich published with his colleagues an account of how and
why the one-partner system might have spread as a social norm. The paper points
out that marriage customs are not the same as mating strategies. (They are
related, though: We tend to internalize the rules of the society we live in, so
"doing right" becomes its own reward.) The authors argue that when a
society gets big enough and sufficiently complex, it's advantageous for its
culture to promote monogamy, or at least monogamishness.
Why? Because polygamy causes problems. Henrich, et al.,
review a large amount of evidence to support the claim that the multiwife
approach leaves lots of men unmarried and so inclined to act in risky, angry
ways. These bachelors are a menace: They increase the rates of crime and
conflict, and lower productivity. In China, for example, a preference for male
babies skewed the gender ratio quite dramatically from 1988 to 2004. In that
time, the number of unmarried men nearly doubled, and so did crime. In India,
murder rates track with male-to-female ratios across the country's states.
Using these and other data, the authors argue that a culture of monogamy would
tend to grow and thrive. It would be the fittest in its niche.
Of course it's also possible that high rates of conflict
lead to cases of polygamy. Walter Scheidel points out that the ancient ban on
multimarriage was suspended near the end of the Peloponnesian War, with so many
soldiers dead that potential husbands were in short supply. Which raises the
tricky question of how monogamy relates to war: Some have argued that
pair-bonding leads to larger, stronger armies and more battle-ready people.
Henrich, et al., suggest the opposite, that men with wives are less inclined to
go to war, which weakens despots and promotes democracy.
The answer may be something in the middle, as it often is
when it comes to the science of monogamy. Some cultures have made the practice
into law and others haven't. Even our human physiology seems undecided on the
issue. At every level of analysis, it's hard to say exactly what we are or how
we live. We're faithful and we're not. We're lovers and we're cheaters.
Friday, 5 October 2012
Do Animals Get Depressed?
:'(|) |
(National Geographic.com, 4, Oct 2012) - Primates, rodents may show signs of sadness, study suggests.
Learning more about depression in animals could one day
benefit humans, say scientists who believe that mammals share the same basic
wiring in their brain for emotions as humans do. (Although not every scientist
agrees with that premise.)
In the October 5 issue of Science, Assistant Professor of
Neuroscience Olivier Berton and his colleagues at the University of
Pennsylvania reviewed recent studies of rodents, primates, and fish who lacked
interest in their environment and their fellow animals.
We spoke with Berton about what we do—and don't—know about
animal depression.
Do animals get depressed?
Depression is diagnosed in humans based on a list of
symptoms that are all very subjective. Common core symptoms include feelings of
guilt, thoughts of death, and loss of pleasure. Because animals can't
communicate even if they have these kinds of experiences, strictly the answer
is: We can't say.
What signs may indicate if an animal is depressed?
There are certain aspects of the disease that may be
measured in animals. One of the core symptoms of depression is anhedonia, the
decrease and loss of interest in pleasurable activities. We measure interest in
food that animals like a lot or in motivation for sexual activity. We also
measure how they are interacting socially with other animals in the group, and
changes in sleep patterns and daytime activities. Another behavior that has
been used frequently to measure animal depression is whether they readily give
up when exposed to a stressful situation.
What animals seem to exhibit signs of depression?
Definitely the most convincing observations derive from
nonhuman primates. Based on behavioral observation, trained observers can say a
monkey looks depressed. Because their emotional behaviors are similar to that
of humans, just by looking at their facial expressions or the way their gaze is
directed, we can get an indication of whether an animal may be experiencing
sadness.
Can you really study animals in this environment?
One problem is that many lab studies in primates and rodents
are conducted in captive animals that are raised in relatively impoverished
conditions compared to their natural habitat. This can cause depression-like
changes. Currently there is not a lot of data available that compares animal
emotional behaviors in the wild versus in laboratory setting.
How would animals deal with depression in nature?
I don't know. There are very few systematic studies of this
kind. It is possible that behavioral disorders in animals in the wild may
impair their chances of survival. Maybe there is a point where they cannot deal
and are more easily preyed upon.
Could domestic animals be depressed?
Veterinarians frequently give antidepressants to dogs to
treat their behavioral disorders. For example, if an owner leaves the house and
the dogs experience stress related to being separated, they may develop
abnormal behaviors such as scratching themselves until they bleed or eating the
door. These are thought to represent canine versions of psychiatric disorders.
Although human treatments seem to work in dogs, large-scale studies are
lacking.
Thursday, 4 October 2012
Human brains grow bigger in the womb than chimpanzee's
(New Scientist.com,
25, Sept 2012) - Chimps may be
similar to us in many ways but they can't compete when it comes to brain size.
Now for the first time we can see when the differences emerge by tracking the
brain development of unborn chimps.
As seen in this video, Tomoko Sakai and colleagues from
Kyoto University in Japan subjected a pregnant chimp to a 3D ultrasound to
gather images of the fetus between 14 and 34 weeks of development. The volume
of its growing brain was then compared to that of an unborn human.
The team found that brain size increases in both chimps and
humans until about 22 weeks, but after then only the growth of human brains
continues to accelerate. This suggests that as the brain of modern humans
rapidly evolved, differences between the two species emerged before birth as
well as afterwards.
The researchers now plan to examine how different parts of
the brain develop in the womb, particularly the forebrain, which is responsible
for decision-making, self-awareness and creativity.
Busy Days at Living Links (Edinburgh Zoo)
(Living Links.org, 3, Oct 2012) - Over the past 2 weeks the Living Links team has had some
busy days with visitors.
On Sunday the 23rd of September we had the St Andrews
University PsychSoc visit Budongo and Living Links. They received an intro talk
from Prof Andy Whiten and had guided tours from the Budongo keepers and Living
Links research staff. They even had a chance to see a live demonstration of
Mark Bowler and Emily Messer’s research into fur rubbing with capuchin monkeys.
"Feed me humans" |
Monkey Medicine – A mini- documentary about fur rubbing can
be viewed at http://vimeo.com/48287364
Then on Monday evening of the 24th of September delegates
from the Animal Concepts Conference entitled Animal Welfare: Emotion, Cognition
and Behaviour enjoyed two ‘talkettes’ by Prof Andy Whiten, one an introduction
to the Living Links/Budongo Consortium and the other on primate minds.
The delegates also received tours of both facilities and
enjoyed a brief photo shoot in the rain at our Primate Family Tree.
"Come here random zoo folk, we need a publicity photo" |
Also as part of the Animal Concepts conference Dr Alex Weiss
of our Living Links board gave a talk on animal personality and welfare.
"This my dear friends is a wild CHAV" |
To view some of Dr.Weiss’s work on personality, visit the
website below http://www.sciencedirect.com/science/article/pii/S0003347212001157
Finally, yesterday our Living Links Team presented a variety
of talks to the RZSS Adult Class and again they received tours of our
facilities, including a visit to the thick billed parrots with Dr Amanda Seed
to see our birds partake in some cognitive research.
"If that bird shits on me again...." |
Thursday, 20 September 2012
Ancient Tooth May Provide Evidence of Early Human Dentistry (and Bee King)
Beeswaxed Tooth - If you squint hard enough you can make out the face of a man wearing a wicked mad hat. Clearly, King of the Bees. |
ScienceDaily (Sep. 19, 2012) — Researchers may have uncovered new evidence of ancient dentistry in the form of a 6,500-year-old human jaw bone with a tooth showing traces of beeswax filling, as reported Sept. 19 in the open access journal PLOS ONE.
The researchers, led by Federico Bernardini and Claudio
Tuniz of the Abdus Salam International Centre for Theoretical Physics in Italy
in cooperation with Sincrotrone Trieste and other institutions, write that the
beeswax was applied around the time of the individual's death, but cannot
confirm whether it was shortly before or after. If it was before death,
however, they write that it was likely intended to reduce pain and sensitivity
from a vertical crack in the enamel and dentin layers of the tooth.
According to Tuniz, the severe wear of the tooth "is
probably also due to its use in non-alimentary activities, possibly such as
weaving, generally performed by Neolithic females."
Evidence of prehistoric dentistry is sparse, so this new
specimen, found in Slovenia near Trieste, may help provide insight into early
dental practices.
"This finding is perhaps the most ancient evidence of
pre-historic dentistry in Europe and the earliest known direct example of
therapeutic-palliative dental filling so far," says Bernardini.
Journal article: Federico Bernardini, Claudio Tuniz, Alfredo
Coppa, Lucia Mancini, Diego Dreossi, Diane Eichert, Gianluca Turco, Matteo
Biasotto, Filippo Terrasi, Nicola De Cesare, Quan Hua, Vladimir Levchenko.
Beeswax as Dental Filling on a Neolithic Human Tooth. PLoS ONE, 2012; 7 (9):
e44904 DOI: 10.1371/journal.pone.0044904
Wednesday, 19 September 2012
Caws and Effect (AMA)
"Reddit, what have I gotten myself into?" |
Alex Taylor takes your questions on Reddit (AMA)
Get your crow cognition questions ready for Alex Taylor as he takes on Reddit /science/ in an AMA (Ask Me Anything) - Sept, 19, 23:00 GMT
Link: Reddit.com/r/science
Tuesday, 18 September 2012
The mysterious, "You don't understand me!", workings of the adolescent brain
"Oh such juicy brains there are here at TED....mmmm"
(TED, 18, Sept, 2012) - Why do teenagers seem so much more impulsive, so much less self-aware than grown-ups?
Crows can 'reason' about causes, a recent study finds
Curious crow is curious |
(BBC Nature, 18, Sept, 2012) - Tool-making crows have the ability to "reason", say scientists.
In an experiment, researchers found that crows were more
likely to forage when they could attribute changes in their environment to a
human presence.
This behaviour may suggest "complex cognition",
according to a study published in the Proceedings of the National Academy of
Sciences. Until now the ability to make inferences based on causes has
been attributed to humans but not animals.
The study was a collaboration between researchers from the
University of Auckland, New Zealand, the University of Cambridge, UK and the
University of Vienna, Austria.
In their experiment eight wild crows used tools to remove food from a box. Inside the enclosure there was a stick and the crows were tested in two separate series of events that both involved the stick moving.
In one instance a human entered the hide and the stick
moved. In the other, the stick still moved but no human entered. On the occasions when no human was observed entering the
hide, the crows abandoned their efforts to probe for food using a tool more
frequently than they did when a human had been observed.
According to the scientists, the study proved that crows
attributed the stick's movement to human presence.
The results indicated that neither age nor sex was a
predictor of the behaviour with juveniles, males and females displaying the
same behaviour. Scientists said that the kind of "reasoned
inference" shown by the New Caledonian crows under these controlled
conditions could also be utilised in the wild to anticipate danger or food.
The study is the first to suggest that animals have the
ability to make reasoned inferences, although scientists added that the phenomenon
could be more common among animals than previously thought.
Journal reference: New Caledonian crows reason about hidden causal agents - http://www.pnas.org/content/early/2012/09/10/1208724109
Monday, 17 September 2012
Crows can remember and differentiate human faces
"I know I know you" - The Crow (1994) |
(New Scientist, Sept, 10, 2012) - You can
run from a crow that you've wronged, but you can't hide. Wild crows remember
human faces in the same way that mammals do.
Crows
can distinguish human faces and remember how different people treated them,
says John Marzluff of the University of Washington in Seattle.
To work out how the crows process this information, Marzluff had members of his team wear a latex mask as they captured 12 wild American crows (Corvus brachyrhynchos). The crows learned to associate the captor's mask with this traumatic experience. While in captivity, the crows were fed and looked after by people wearing a different mask.After four weeks, the researchers imaged the birds' brains while they were looking at either the captor or feeder mask. The brain patterns looked similar to those seen in mammals: the feeder sparked activity in areas involved in motivation and reward, whereas the captor stimulated regions associated with fear.
The result makes sense, says Kevin McGowan of Cornell Lab of Ornithology in Ithaca, New York. Crows don't mind if humans are in their habitat – but they need to keep a close eye on what we do.
Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1206109109
Size Does Matter. Brain Size!
Big brains, but all they want to talk about is mackerel. |
(Discover Magazine, Sept, 11, 2012) - Every whale and dolphin evolved from a deer-like animal with slender, hoofed legs, which lived between 53 and 56 million years ago.
Over time, these ancestral creatures became more streamlined, and their tails widened into flukes. They lost their hind limbs, and their front ones became paddles. And they became smarter. Today, whales and dolphins – collectively known as cetaceans – are among the most intelligent of mammals, with smarts that rival our own primate relatives.
Now, Shixia Xu from Nanjing Normal University has found that
a gene called ASPM seems to have played an important role in the evolution of
cetacean brains. The gene shows clear signatures of adaptive change at two
points in history, when the brains of some cetaceans ballooned in size. But
ASPM has also been linked to the evolution of bigger brains in another branch
of the mammal family tree – ours. It went through similar bursts of accelerated
evolution in the great apes, and especially in our own ancestors after they
split away from chimpanzees.
It seems that both primates and cetaceans—the intellectual
heavyweights of the animal world—could owe our bulging brains to changes in the
same gene. “It’s a significant result,” says Michael McGowen, who studies the
genetic evolution of whales at Wayne State University. “The work on ASPM shows
clear evidence of adaptive evolution, and adds to the growing evidence of
convergence between primates and cetaceans from a molecular perspective.”
For decades, we’ve known that similarities between primate
and cetacean intelligence run deep. For a start, both groups have members with
unusually big brains. We humans have brains that are 7 times bigger than you’d
expect for an animal of their size. The equivalent number is 2-3 for chimps and
some monkeys, and 4-5 for some dolphins.
Over the last decade, scientists have identified seven genes
that are linked to primate brain size. They’re called MCPH1 to MCPH7 (ASPM is
the fifth in the line). Faults in these genes can lead to microcephaly – a
developmental disorder characterised by a debilitatingly small brain.
McGowen had already shown that, unlike in humans, MCPH1
doesn’t neatly correlate with brain size in cetaceans. Xu wanted to see if ASPM
would be more interesting. He sequenced the gene in fourteen species of
cetaceans, from the bottlenose dolphin to the minke whale. He then compared
these to known sequences from 18 other mammals, including several primates and
the hippopotamus (the closest living relative to cetaceans).
Xu found that ASPM went through two periods of strong
positive selection – where beneficial new versions of the gene spread through a
population. The first coincides with the point when toothed whales (like sperm
whale and dolphins) split away from the baleen whales (like blue, fin and
humpback whales). Their brains got bigger. The second period marks the split of
the toothed whales into the delphinoids (including all oceanic dolphins and
porpoises) and all the others. The delphinoids’ already big brains got bigger
still.
Xu also found signatures of positive selection within the
ASPM genes of primates, but not in any other mammal groups. During their
history, both groups must have experienced some evolutionary pressures that
meant bigger brains suddenly became advantageous. We can only speculate what
these might have been. For cetaceans, the toothed whales evolved to navigate
with echolocation, and may have needed a larger brain to process the
information from all the returning echoes. The delphinoids may owe their larger
brains to the mental demands of living in large, complex social groups. (Both
hypotheses have been on the cards for some time, and Xu’s ASPM discovery
doesn’t provide a smoking gun for either.)
What does ASPM actually do? The gene is activated in neuroblasts,
the embryonic cells that eventually divide into neurons. It helps to create
structures in dividing cells that send a full complement of DNA into each
daughter. If ASPM isn’t working properly, the neuroblasts cannot divide evenly,
and brains get smaller. It’s not clear how the reverse happens – how changes in
ASPM lead to bigger brains, but it’s now clear that this has happened in at
least two mammal groups.
Xu found certain mutations that were associated with the
bigger brains of toothed whales, and others that are associated with the even
bigger brains of delphinoids. What these mutations did is anyone’s guess, and
something that will take a lot of experimental work to uncover.
Here’s one critical nugget, though: they’re different to the
changes you see in primates. The same gene may have enlarged the brains of both
groups, but it did so in different ways. And undoubtedly, other genes were also
involved.
(To close, here’s possibly my favourite ever example of
convergent evolution, which also involves cetaceans. Toothed whales and some
bats both use echolocation, and their abilities depend on the same changes to
the same gene – Prestin. This was discovered at the same time by two
independent groups of researchers, one led by Yang Liu and the other by Ying
Li!)
Reference: Xu, Chen, Cheng, Yang, Zhou, Xu, Zhou & Yang.
2012. Positive selection at ASPM gene coincides with brain size enlargements in
cetaceans. Proc Roy Soc B.
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