Foxglove: IELTS Academic Reading practice test

A honeybee that has found a good patch of flowers returns to the hive and, in the darkness of the comb, performs a figure of eight. The straight section in the middle of that figure, during which the insect vibrates her body rapidly from side to side, is what carries the information. Karl von Frisch established in the 1940s what it means. The angle between that straight run and the vertical corresponds to the angle between the direction of the food and the direction of the sun, transposed from the horizontal world outside onto the vertical face of the comb. The longer the run lasts, the further away the food is. The bees attending, who are in complete darkness and cannot see the dancer at all, follow her with their antennae and take the message by touch and by the sound she makes.

The claim met resistance for a generation. In the 1960s two American researchers argued that the dance might be beside the point, and that recruits find a food source in the ordinary insect manner, by following the scent of the flowers carried into the hive on the dancer's body. The objection was a reasonable one; odour plainly does play a part, and bees can be recruited by scent alone. The question was settled in stages, and most decisively by an experiment in which recruits leaving the hive were fitted with tiny transponders and followed by radar. Bees that had attended a dance and were then released at an unfamiliar point flew the distance and the compass bearing the dance had specified, ending in empty air at exactly the offset one would predict.

How a bee measures a distance she has flown turns out to be unexpected. The obvious answer is effort, and the obvious answer is wrong. Bees judge distance by how far the image of the ground beneath them travels across their eyes during the journey, which means the reading depends on how close the ground is and how cluttered it happens to be. Bees trained to fly along a narrow tunnel lined with a bold pattern experience a great deal of visual motion over a very short flight, and on returning they dance as though they had travelled hundreds of metres. A bee crossing a wide, featureless lake at height makes the opposite error for the same reason.

Direction depends on the sun, which presents a difficulty of its own, because the sun moves. A bee dancing at ten in the morning and a bee dancing at four in the afternoon would indicate quite different bearings for the same patch of flowers unless something corrected for the interval, and something does. The insect carries an internal clock accurate enough to compensate for the sun's apparent motion, and a forager shut in the dark for several hours will dance, on release, at the angle appropriate to where the sun has got to rather than where it was when she last saw it. On overcast days bees fall back on the pattern of polarised light across the sky, which preserves the sun's position even when the disc itself is hidden.

The dance is also a mechanism for taking decisions. A forager dances more persistently for a richer patch, so the number of dances advertising a site is roughly proportional to how good it is, and a recruit who samples several dancers before setting out is in effect drawing a weighted sample of the colony's current information. The same machinery handles the most consequential decision a colony ever makes. When a swarm leaves to find a new home, scouts inspect candidate cavities and return to dance for them on the surface of the cluster; those who have seen a better site dance longer, others go and check for themselves, and when the number of scouts committed to a single site passes a threshold the swarm takes off. No individual bee compares the options. The comparison is carried out by the group.

It is tempting, and it has often been tempting, to call this a language, and the temptation is worth resisting, not because bees are unimpressive but because the word buys nothing. The dance has no grammar: there is no way of combining elements to produce a new meaning, and no element that modifies another. It refers to one kind of thing only, a location and its quality, and it cannot be used to refuse, to ask a question or to mislead. What it does possess, and what genuinely sets it apart from almost every other animal signal, is displacement: it conveys information about something neither present nor visible, which very few communication systems outside our own can manage at all.

The dance has lately acquired a practical use that von Frisch could not have anticipated. Because each dance encodes a bearing and a distance, a researcher who records enough of them from a single hive can plot where its foragers are going, and so survey the forage available across several square kilometres of countryside without walking any of it. Studies using this method report that colonies must travel considerably further for food in intensively farmed landscapes than in suburban ones, where gardens supply a long and varied flowering season. The bees, in effect, have been persuaded to do the fieldwork.

What remains most striking is the economy of the thing. A honeybee has fewer than a million neurons, something like a hundred thousandth of the number in a human brain, and with them she solves a navigational problem involving a moving celestial reference, an internal clock, an odometer calibrated in visual motion, and a means of transmitting the result to an audience that cannot see her. Whatever intelligence turns out to be, a good deal of what we admire in it can evidently be done with very little of the machinery we had assumed was necessary.

In 1968 an American biologist published a short essay containing a parable that has shaped policy ever since. Imagine a pasture open to all. Each herdsman gains the whole benefit of adding another animal, while the cost of the extra grazing is shared among everybody, so each finds it rational to add animals until the pasture is destroyed. The conclusion drawn was stark: a resource held in common is doomed, and the only remedies are to divide it into private holdings or to place it under the control of a state with the power to compel. The essay became one of the most cited papers ever written in the sciences and entered the syllabus of every discipline concerned with the environment.

The trouble with the parable is that it does not describe a commons. What it describes is open access: a resource to which anybody may help themselves, subject to no rules, no membership and no monitoring. Historical commons were not like that. English common land was governed by stint, a limit on the number of animals each commoner could turn out, fixed by custom and enforced through manorial courts that fined offenders and recorded the fines; rights were attached to particular holdings and could not be acquired by simply arriving. The author himself acknowledged, much later, that he should have written about the tragedy of the unmanaged commons, which is a rather different and much less interesting claim.

The empirical answer took thirty years to assemble and came from Elinor Ostrom, who spent her career collecting cases. Irrigation systems in Nepal, allocating water among hundreds of farmers with no government involvement. Alpine pastures in Switzerland, held in common since the thirteenth century and still neither overgrazed nor privatised. Inshore fisheries in Japan and Turkey where the fishermen themselves assigned and rotated the good spots. Forests in India and Mexico. Many of these had been functioning for centuries; some, on close examination, were failing badly; and the distribution of successes and failures was not random. In 2009 she became the first woman to receive the Nobel memorial prize in economics, for work whose central finding was that the received alternatives were not the only ones.

What distinguished the arrangements that lasted was a set of features that recur with striking regularity. The boundaries of the resource and of the group entitled to use it are clear. The rules fit local conditions rather than a template. The people bound by the rules can take part in changing them. Monitoring is done by people accountable to the users, often the users themselves in rotation. Penalties for a first offence are mild and escalate only for repetition. There is a cheap and quick way of settling disputes. The right of the group to organise itself is at least not denied by the government above it. And where the resource is large, these arrangements are nested inside one another rather than replaced by a single authority.

It is important to be clear about where this does not reach. Self-governance of this kind is observed among groups small enough that members know one another and expect to go on dealing with each other for years. It works on resources that stay put, or at least stay within the boundary: a pasture, a forest, an irrigation canal, an inshore shellfish bed. It does considerably worse where the resource moves across jurisdictions, as migratory fish do, where the users are numerous and anonymous, where the value of the resource rises suddenly because an outside market has appeared, and where the group is divided by large differences of wealth or power. The atmosphere satisfies none of the conditions, which is why the analogy is so often invoked there and so rarely useful.

The most serious methodological objection comes from Anselm Brodie, who works on institutions in developing economies. Ostrom's cases, he argues, were selected by looking for commons that had survived, and a set of survivors will naturally share whatever features survivors have; the principles derived from them describe the winners without establishing that the features caused the winning. He adds a practical complaint that is harder to dismiss. The eight principles have been taken up by development agencies as a checklist, imposed on communities from outside in a matter of months, and the resulting committees frequently turn out to be institutions on paper and nothing at all in the village, with the added effect of displacing whatever arrangement was there before.

The first objection has since been addressed in part. Several large studies have gone back to databases of common-pool resource cases, including the failures, and asked whether the principles predict which arrangements endure; the answer has generally been that they do, less strongly than the original account implied but well beyond chance. The second objection is not really an objection to the research at all. A finding about what makes institutions durable, applied by people in a hurry as a template to be installed, will produce bad institutions, and that tells us something important about how evidence travels but nothing about whether the evidence is sound.

What the whole episode illustrates is how much work a vivid example can do. For thirty years a parable about a pasture, which described an arrangement that scarcely existed, was treated as a demonstration that communities cannot manage what they hold together, and policies were built on it: fisheries privatised, forests nationalised, grazing rights extinguished, frequently with results worse than what preceded them. The correction, when it came, did not show that communities always succeed; a great many do not. It showed that the question is empirical. Which institution suits which resource is something to be found out, case by case, and the confident answers of the 1970s were not findings. They were a story.