Michael BellOctober 22, 2014
Recently published research in Proceedings of the National Academy of Sciences
suggests that early human use of fire had major social implications as well
as the more commonly described dietary and physiological aspects.
Dr Polly Wiessner, Professor of Anthropology at the University of Utah, analysed
the content of 174 recorded or documented day and nighttime conversations among
Kalahari Bushmen, and says that sitting around a campfire at night enables conversations,
storytelling, and social bonding more effectively than daytime interactions.
"I found this really fascinating difference between conversations by firelight
and conversations in the day," says Wiessner. "The day is harsh, you
see the realities, you see the facial expressions, there's work to be done,
and there's social regulation, and at night people kind of mellow out. The day
is productive time for hunting and gathering and the firelight changed our circadian
rhythm, so we stayed awake much longer and it gave a whole new time and space,
and it was a time when no work could be done," she says. "I think
it had an impact on our cognitive evolution; the stories are told in wonderful
language, perhaps increasing linguistic skills and the imagination . . . when
you're out in the dark by a fire, so many of the stimuli are shut out and your
imagination then takes off."
Weissner notes that fireside conversations often focus on wider social contexts
and relationships among a far-flung network of acquaintances, some of whom may
even be dead.
Humans didn't invent fire, of course; they learned to control it, and to use
it for cooking, heating, manufacture, deterrence of predators. And now it seems
that it may have played a considerable role in the development of language and
social structures. Based on archeological evidence, early human use of fire
is dated to between 400,000 and one million years ago, and is commonly associated
with Homo erectus, although many commentators think that fire came into regular
use only towards the end of that time period, perhaps driven at least partly
by the need to cook food to support the metabolic demands of the enlarging human
300-400,000 years ago is (very approximately) the period during which homo
erectus began its gradual transition into homo sapiens, and a time at which
spoken language was beginning itss rapid development alongside the elaboration
of the human social group. Wiessner's 'wonderful language' wouldn't yet exist,
but it's not hard to imagine that firelight would have played a considerable
role in the crucible of linguistic and societal development.Michael BellAugust 27, 2014
There have been many academic studies linking increased brain size in mammals to social complexity: it doesn't seem very contentious to suggest that dealing with the complex behaviours of up to 150 group members would require more brain cells than solitary life. Or at least it seems likely to have been true until the state began to take over management of social relationships: someone should study whether couch potatoes have smaller brains than professional carers. But there have been relatively few rigorous attempt to correlate brain size with particular social behaviours.
Now a team in the University of Colombia's Department of Zoology has carried out research, published in the Journal of Ecology and Evolution, which demonstrates a clear correlation between brain size and the need to care for offspring. OK, it's in stickleback fish, and they're not even mammals, but what seems particularly convincing is that it's the males that have larger brains than the females, and it's the males who do the caring in that particular species. Of course this will be unsurprising to human females, who have long known that looking after their children requires more mental capacity than going down to the pub and watching football, but it does offer an escape route from female domination for those males who are prepared to search for their inner carers.
Well, enough frivolity. In the study, 'Reversed brain size sexual dimorphism accompanies loss of parental care in white sticklebacks', researchers compared regular male sticklebacks to male white sticklebacks, which do not tend to their offspring, and found a clear difference in brain size. They found evidence that this change in male behaviour – giving up caring for the young – occurred at the same time the white stickleback evolved a smaller brain. The white stickleback is a newly-emerged species that only diverged from other sticklebacks 10,000 years ago.
Said lead author Kieran Samuk, a PhD student in UBC's Dept. of Zoology: "This suggests that regular sticklebacks have bigger brains to handle the brain power needed to care for and protect their young. This is one of the first studies to link parental care with brain size."
The association between greater brain size and social complexity is of course demonstrated across many species, not just mammalian. How far back could we go, then in terms of demonstrating a linkage between social (groupish) behaviour and brain size?
Before fish, in general terms, from an evolutionary perspective, came sharks (chondrichthians). They certainly have social behaviours, and there is a wide variety of brain designs and sizes among contemporary sharks. Interesting then, to know if any correlation could be established between shark socializing and their brain size. Then come the invertebrate sea creatures, and another level of difficulty in terms of research. We need submersible robot PhDs, and that is a stretch, currently.
M G BellJanuary 6, 2014
It's well known that cuckoos parasitize the nests of other birds, and the benefit
to the cuckoos of this "brood parasitism" is obvious; what is not
clear is why young members from other nests of the species that is being parasitized
sometimes help to feed an intruder cuckoo chick.
Research carried out by a team led by evolutionary biologist Dr Naomi
Langmore of the Australian National University has studied this phenomenon,
known as "cooperative breeding", concluding that it is because
the continued presence of a group of the host species acts to deter the cuckoos
from placing their eggs in the hosts' nests in the first place.
"It's a very puzzling type of behaviour," says Langmore. While at
first it was thought that the reason for the young birds to hang around was
simply that they helped to raise more chicks, the research has suggested that
the group mechanism is more credible.
The researchers studied colonies of speckled warblers and fairy wrens, finding that
a team of four or five group helpers made it much more likely the hosts could
defend their nests against cuckoos than a smaller team of only two or three
birds, not being enough individuals to "mob" cuckoos and drive them
"Maybe the main benefit cooperative breeding provides is in safety in
numbers," says Langmore.
"Brood parasites lay their eggs in the nests of other birds and then they
abandon their young to the care of the host," says Langmore. "So the
host loses that brood then they invest weeks or months rearing the cuckoo chick
and very often have no time left to breed again after that. This is a massively
costly thing for the host."
The research showed a clear correlation between the size of groups of fairy
wrens and their ability to resist parasitism.
"If there are four or more individuals in the group they almost never
get parasitized by a cuckoo whereas the small groups of two or three individuals
are much more likely to get parasitized."
"We can't say that brood parasitism actually caused the evolution of cooperative
breeding because we can't say which one came first," says Langmore. "But
we can say that it provides a very strong selective force for the maintenance
of cooperative breeding."M G BellNovember 23, 2013
Research at UCLA on the coloration and complexity of primate faces (monkeys and apes) has shown that there is a correlation between those attributes and the size of social groups, although the effect was less marked among apes as opposed to monkeys, which is thought to be because apes have a more highly developed set of facial expressions which they can use to aid recognition. Past a certain point, muscular expressivity might be a more flexible way of demonstrating individuality than coloration and physiognomical variation.
"Humans are crazy for Facebook, but our research suggests that primates have been relying on the face to tell friends from competitors for the last 50 million years and that social pressures have guided the evolution of the enormous diversity of faces we see across the group today," said Michael Alfaro, an associate professor of ecology and evolutionary biology in the UCLA College of Letters and Science and senior author of the study.
"Faces are really important to how monkeys and apes can tell one another apart," he said. "We think the color patterns have to do both with the importance of telling individuals of your own species apart from closely related species and for social communication among members of the same species."
"Our research suggests increasing group size puts more pressure on the evolution of coloration across different sub-regions of the face," Michael Alfaro said.
Other variables affected coloration such as distance from the equator and the degree of forest cover (true also of humans), but the degree of facial complexity was linked only to group size.
"We found that for African primates, faces tend to be light or dark depending on how open or closed the habitat is and on how much light the habitat receives," Alfaro said. "We also found that no matter where you live, if your species has a large social group, then your face tends to be more complex. It will tend to be darker and more complex if you're in a closed habitat in a large social group, and it will tend to be lighter and more complex if you're in an open habitat with a large social group. Darkness or lightness is explained by geography and habitat type. Facial complexity is better explained by the size of your social group."
Evidently, one must distinguish between group behaviour linked to mutual protection (such as among shoals of fish or herds of bison) and intra-group 'social' behaviour in which characteristics are attributed to individuals, requiring a mechanism to distinguish one individual from another. But it would be unjustified to make a hard and fast distinction between such types of groups. No doubt there is a continuum of intermediate situations between, at the most basic, a group whose members are simply recognizable as conspecifics because of their size, shape, color, or smell, and a complex social group in which individuals' behaviour towards each other depends on memory of previous interactions with a particular individual, emotional drives and external situations (to pick just a few out of many factors determining inter-personal behaviour).
It is an interesting question, as to how far back up the evolutionary tree animals first became able to distinguish indivuals from conspecifics in general. Do dogs recognize each other? – obviously yes; do lizards recognize each other? – hmmm; do sharks recognize each other? There is a lot we don't know! Dmitri Dergun29th April 2013
Research led by the University of Colorado Boulder seems to show that there are mechanisms in corn reproduction that favour seeds with homogeneous parentage: each seed consists originally of two components, an embryonic corn plant and an endosperm which contains nutrients used in the growth of the embryonic plant. It is possible for these two components to have genetically different 'parents', and the research found that plants whose two components had identical parents grew better than plants where the parentage was different.
CU-Boulder Professor Pamela Diggle says:
"It is fairly clear from previous research that plants can preferentially withhold nutrients from inferior offspring when resources are limited. Our study is the first to specifically test the idea of cooperation among siblings in plants."
"The results indicated embryos with the same mother and father as the endosperm in their seed weighed significantly more than embryos with the same mother but a different father. We found that endosperm that does not share the same father as the embryo does not hand over as much food -- it appears to be acting less cooperatively."
William "Ned" Friedman, a professor at Harvard University who helped conduct research on the project while a faculty member at CU-Boulder, said:
"One of the most fundamental laws of nature is that if you are going to be an altruist, give it up to your closest relatives. Altruism only evolves if the benefactor is a close relative of the beneficiary. When the endosperm gives all of its food to the embryo and then dies, it doesn't get more altruistic than that."
These reports of the results use words like 'mother', 'father', 'cooperation', and 'altruism', which seems anthropomorphic, or whatever the equivalent word would be for the attribution of animal characteristics to vegetables. (Think screaming cabbages!) So let's be clear: this is a chemical mechanism which gives nutritional preference to more closely related organisms. It's a stretch to call it altruism or cooperation; but it does show that evolution favours kinship.
Altruism is most often thought of as a 'groupish' characteristic, ie it evolves to favour cooperation between members of a group, along with empathy and other characteristics of advanced forms of animal species, and it is characterized as a cognitive process.
A zoological definition goes: 'instinctive behavior that is detrimental to the individual but favors the survival or spread of that individual's genes, as by benefiting its relatives'.
No-one is going to credit ears of corn with cognitive abilities, and even the word 'instinct' seems inappropriate; yet it seems that we may need to broaden our understanding of altruism if it can be delivered chemically. On the other hand, everyone is happy to accept the idea that evolution can function as well for corn as for sentient creatures. Perhaps then the reality is that groupishness, or altruism or cooperation or what you will, is something that emerges among all life forms and has bio-chemical underpinnings.
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