There is a tension between the conception of cognition as a central nervous system (CNS) process and a view of cognition as extending towards the body or the contiguous environment. The centralised conception requires large or complex nervous systems to cope with complex environments. Conversely, the extended conception involves the outsourcing of information processing to the body or environment, thus making fewer demands on the processing power of the CNS. The evolution of extended cognition should be particularly favoured among small, generalist predators such as spiders, and here, we review the literature to evaluate the fit of empirical data with these contrasting models of cognition.
Spiders do not seem to be cognitively limited, displaying a large diversity of learning processes, from habituation to contextual learning, including a sense of numerosity. To tease apart the central from the extended cognition, we apply the mutual manipulability criterion, testing the existence of reciprocal causal links between the putative elements of the system. We conclude that the web threads and configurations are integral parts of the cognitive systems. The extension of cognition to the web helps to explain some puzzling features of spider behaviour and seems to promote evolvability within the group, enhancing innovation through cognitive connectivity to variable habitat features.
Graded changes in relative brain size could also be explained by outsourcing information processing to environmental features. More generally, niche-constructed structures emerge as prime candidates for extending animal cognition, generating the selective pressures that help to shape the evolving cognitive system.
Extended spider cognition may help explain some rather unexpected experimental findings. For example, if web building is conceived as a centralised cognitive process, researchers might reasonably expect significant amounts of brain tissue to be dedicated to the organisation of the various behavioural units needed to obtain the final web.
On this view, the ability to build a complex structure such as an orb-web should be correlated with those brain areas devoted to the processing of the multitude of simultaneous cues, of the different kinds of silks and spinnerets to use in different situations, of the organisation of the various components of the structure, such as frame lines, temporary spiral lines, radii, viscid spiral lines, hub building and rebuilding, while monitoring the spatial position of the spider within the emerging structure, and the properties of relevant environmental features, such as gravity, humidity, wind, prey abundance and type, etc. From the centralised cognition standpoint, these aspects of the web should be represented internally, in the organisation of a potentially relatively large and costly CNS tissue that would yield high foraging payoffs.
Conversely, from the extended cognition perspective, if the cognition for web building extends to the web itself, the amount of CNS neural tissue dedicated to web building would be expected to be significantly smaller than what the centralised cognition stance anticipates. It follows that the two approaches to cognition have contrasting predictions about the relative size of spider CNS tissue dedicated to solving specific tasks.
By standing on the shoulders of giants, humans have built the sophisticated high-tech world we live in today. Tapping into the knowledge of previous generations—and those around us—was long thought to be a “humans-only” trait. But homing pigeons can also build collective knowledge banks, behavioral biologists have discovered, at least when it comes to finding their way back to the roost. Like humans, the birds work together and pass on information that lets them get better and better at solving problems.
“It is a really exciting development in this field,” says Christine Caldwell, a psychologist at the University of Stirling in the United Kingdom who was not involved with the work.
Researchers have admired pigeon intelligence for decades. Previous work has shown the birds are capable of everything from symbolic communication to rudimentary math. They also use a wide range of cues to find their way home, including smell, sight, sound, and magnetism. On its own, a pigeon released multiple times from the same place will even modify its navigation over time for a more optimal route home. The birds also learn specific routes from one another. Because flocks of pigeons tend to take more direct flights home than individuals, scientists have long thought some sort of “collective intelligence” is at work.
But can pigeons improve this homing ability over generations, building on the knowledge of birds that have come before? The phenomenon, known as cumulative cultural evolution, was considered “arguably unique to humans,” says Dora Biro, a behavioral biologist at the University of Oxford in the United Kingdom.
I have been pondering this final picture that I put into the last essay. Polygonal stonework from ancient Greece. Trying to figure out how it was done. If you wanted to recreate these shapes and fit them together using a flat background and two dimensional paper or card pieces, it would be fiddly and time consuming to get all the edges cut perfectly to make tight joints.
But we are not dealing with paper which can be cut with a blade or scissors. Someone has to work away at the surface of the stone, using another harder stone or metal tool. How did they do that ? Trial and error ? Remove some of the surface, place the worked rock into position, so how it fits against its neighbours, take it out, remove some more, gradually getting closer to perfection, repeat, repeat, repeat ?
But some of these walls are made from extremely hard stone. Have you ever tried hitting granite with another piece of granite to peck away at the surface ? And in some cases the stones are enormous, weighing several tons. It would not be practical to put them into a slot, take them out again, and repeat, until they eventually fitted.
And another problem. You can fit two dimensional shapes like a jigsaw puzzle, but these walls are three dimensional. Each stone extends back into the wall and has to fit in that direction too, or else it will rock about on any high point that it rests upon.
I mean, this is why cement mortar is used nowadays in stone walls. Ordinary earth or subsoil can be used in the same way for field walls, and sometimes with added animal hair or lime as a binder for house walls. It saves having to get a perfect flat surface adjoining another perfect flat surface, and the whole business of building a wall becomes much less laborious and more efficient if you use identical regular rectangular shapes like bricks.
Despite the advantage for builders of using regular bricks, it seems that a polygonal wall is, theoretically at least, a stronger construction, because the components link together and spread the load, like arches. So if the ground at the base subsides or the wall is shaken by earthquakes, the mesh of interlinked shapes might hold together.
Apparently someone called Protzen is an acknowledged leading expert on ancient methods of working stone who has recreated some walling, but his idea is the trial and error technique, which is hard to accept if you imagine how many times you’d been to place and replace a boulder weighing several tons. The risks of damage, injury, mishap, involved with shifting very large heavy objects becomes obvious as soon as you try it, even with sophisticated modern equipment. Just getting a large rock up to where you want it in a high wall is daunting. To do it many times until it finally makes a perfect fit seems incredible. Some of the joints are so tight you cannot insert thin paper or a razor blade.
Unless of course, it was easy or easier, for them, because of some other factor, the possibility that they had abilities or equipment the knowledge of which is now lost to us. It’s easy to speculate about magical powers or giants or whatever, but I’m quite hardheaded and left brainish enough, that I want some actual evidence to back up the conjecture. It’s not that I reject the possibility, I hope I’m open to any ideas, but there’s clearly a cut off point between wild flights of fancy and plausible reasoned suggestions based on something empirical and observable.
This guy has many very wild unconventional ideas, which are interesting, but personally I am not convinced (at all) about most of them.
Whereas I find Brien Foerster more measured and sober in his researches and conclusions.
Unsurprisingly, I am not the first to be puzzled by all this, here is a good page about the matter, where I was delighted to learn that the folk of Mallorca like to have gaps between the stones because they serve as refuges for snails. Not for the benefit the snails of course, but because the Mallorcans like to eat them. The large species of snail that we have in UK is said to have been introduced by the Romans, who, like the French, viewed them as a delicacy. It’s odd that the taste did not last, and many British see them as rather slimy, disgusting, inedible, yet related molluscs from the seaside, winkles, cockles, are relished by some.
Polygonal “Lesbian” masonry was most popular during the 6th century B.C., and there is a tendency to date its origins from the previous century; the 4th century B.C., on the other hand, saw it fall into almost complete disuse in the Greek world.
The final dressing of those stone blocks used as facing clearly shows a curvilinear form which also influences the sharp-edged joints. The perfect matching of adjacent blocks (both in terms of the cut of the joints and of the coplanar nature of the faces) shows how the curves are result of a calculated choice aimed at creating an expressive figurative effect.
However, it should be said that numerous scholars have failed to recognise the independent nature of polygonal “Lesbian” masonry, considering it a mere variation of classical polygonal masonry. Compared with other forms of polygonal masonry, “Lesbian” masonry is characterised by a severer, more essential finish; again, one of the most frequent methods of dressing the stone involved its standardisation using a hammer, and only on rare occasions was it ever “decorated” with close-knit parallel vertical lines.
One excellent example of polygonal “Lesbian” masonry can be seen at the sacred site of Delphi: the great temenos, dating from the 6th century B.C., features a steep boundary wall (190 x 135 m.) partly built using this particular method, constituting a monumental entrance to this Panhellenic sanctuary.
An even more refined example, to be found at Delphi, consists of the basement of the sanctuary’s central terrace, on which the Temple of Apollo – was to be built: this in fact constitutes one of the finest monumental products of the polygonal “Lesbian” method. In the sanctuary, which contains a multitude of small constructions (votive offerings, memorials, treasuries, votive statues etc.), the plan to integrate the new temple into the surrounding landscape dominated by the huge Fedriadi rocks required considerable work, including the demolition and reallocation of several constructions, in order to create the terrace. The massive basement, built after 548 B.C. in conformity with the surrounding, irregular land, to this very day reveals all of its power to those visitors reaching it from below along the sacred way. As you get to the terrace, you cannot fail to be amazed by the polygonal wall with its perfectly-matching, arabesque-like curvilinear joints. There are a great many inscriptions on the wall (roughly 800), making it one of the most important ancient Greek archives.
Now comes another mystery that is unresolved. Did the people of ancient Greece, Peru, Japan, and many other places, Latvia, Italy, Spain, Egypt, Turkey, Easter Island, invent this technique independently, or did it begin in one location and then get spread by travellers or migrations of people. Some argue that the existence of pyramids in both Egypt and Central America (and China and many other places) demonstrates shared culture or communication. Others argue that the matter is unproven. There’s only so many ways that you can build walls, and if you pile up earth, sand, stones, you almost automatically and inevitably get a pyramid shape.
If we look at the distribution of the polygonal style of stonework seen in ancient Greece, Peru, and Egypt, the close similarity between the examples does suggest that the work was done by the same people, because the style is so distinctive. But according to the standard orthodox mainstream teaching, there is not supposed to be any connections at all. The cultures are to be seen as distinct, with no communication between them.
Unfortunately many aspects of human activity do not leave any permanent marks or traces for us to observe. Perhaps people did circumnavigate the globe in sea going vessels in far distant prehistoric times, but unless someone can find a wrecked vessel or some authentic inscriptions or artefacts that prove that they did, it’s only a vague hypothesis. Graham Hancock has gone into the ancient maps which show Antartica, and so forth, and there is Charles Hapgood’s work.
(Sorry for the link. I don’t know why this happens. You might have to copypaste it, Google evilness…)
There are many intriguing hints concerning mysterious people who arrived and taught the locals. I guess that if teams of scores, or even hundreds, skilled in stone technology or whatever, did visit or even stay, relative to the size of the indigenous populations, their genes would probably not be obvious to modern analysis of present day inhabitants.
Afaik, there’s been no examples yet of say, a Peruvian prehistoric individual whose remains have the same DNA signature as someone from ancient Greece, or of an ancient Egyptian in Australia. That sort of thing. When Foerster’s famous elongated heads eventually get proper DNA tests done we may need re-evaluate our ideas. Some of them at least seem to have had pale skin and red hair, and to have been very tall, quite unlike the general indigenous population today.
I think an additional factor which strengthens the argument that actual individuals carried the skill of building polygonal stone walls from say, Egypt or Greece to Peru and Easter Island, is that it’s not only the polygonal shaped rocks, there’s also the very strange protuberances. And a third shared artefact is the key cutouts which were filled with (molten ?) metal to hold adjacent stones together. Or possibly to serve some other function.
Someone must have invented this novelty for the first time somewhere and then shared the idea, but it could have been thought of several time independently. It’s not clear that it is very effective to bind stones together. Probably any great stress would break the metal or force it to pop out of its slot. There are at least two styles, the T bar type and the butterfly type which is like a wood work dovetail joint.
I had been under the impression that all the metal keys had been robbed or corroded away, but I just found that there’s some examples still in situ, and if the source is correct and reliable, they reveal some fascinating information. Clamps found at Puma Punku were made of an unusual alloy, 95.15% copper, 2.05% arsenic, 1.70% nickel, 0.84% silicon and 0.26% zheleza (What is zheleza ? I don’t know. Possibly a muddled translation). It’s said some of the key cuts indicated traces of platinum which melts at 1768 deg. C. so whoever was doing the work must have had some mastery of high temperature smelting of ores in crucibles. We have here examples of the same key idea, although different styles, from Bolivia, Armenia, Tunisia, Syria, Egypt (wooden !), Spain, Sardinia, Persia, Ethiopia and Japan, Maldives, Cambodia, and others (sorry not to be more precise but the auto translations are too garbled to unscramble.)
Ever since someone noticed the similarities between Sanskrit, Latin and English, at least since the 1800’s, linguists and others tried to trace migrations of peoples by reconstructing plausible relationships between the languages. Then, much more recently, academics have tried to map the same sort of movements using DNA analysis.
These two approaches tend to give different mappings which lead to heated debates amongst the scholars and proponents of theories, who strive to reconcile the evidence. But we also have all these material remains. What should we make of the obvious similarities and resemblances between, say, the ancient Greek stuff and the Peruvian stuff ? What’s it telling us ? Perhaps someone will make a theoretical breakthrough, or some new evidence or discoveries will strengthen an argument and make the picture clearer. I try to remain open minded, and find it very difficult to make any decisive statement. More studies are needed.
If you are interested in this topic you might like this post on the same subject I wrote about six months ago