A While it has long been recognized that play affords benefits that last through adulthood, psychologists in the US are now becoming concerned that lack of play could actually be harming their country’s kids. In the past, few children grew up without ample free-play time. But youngsters’ leisure hours are now filled with structured activities such as music lessons and sports. Kids play soccer, Scrabble and saxophone – so why are experts worried that these activities are eating into free play? Most games are fun and sources of learning experiences – fostering group cohesion, for instance, says educational psychologist Anthony Pellegrini. But, Pellegrini explains, ‘games have predetermined rules – set up in advance and followed. Play, on the other hand, does not have rules, so affords more creative responses. Children initiate and create free play, and use their imagination to try out new activities and roles.

B Perhaps most crucially, play helps us develop strong social skills. ‘You don’t become socially competent via teachers telling you how to behave,’ Pellegrini says. ‘Kids learn those skills by interacting with peers, learning what is and isn’t acceptable. They want this thing to keep going, so they’re willing to “go the extra mile” to accommodate their playmates’ desires. Keeping things friendly requires communication – arguably the most valuable social skill of all. Play among peers is the most important in this regard. Studies show that children use more sophisticated language when playing with other children than when playing with adults. In pretend play, for instance, “they have to communicate about something that’s not physically present, so they have to use complicated language to communicate what it is that they’re trying to say,” Pellegrini explains.

C If play helps children become socialized, then lack of play should impede social development – and research suggests that it does. A study of children in Michigan revealed that kids who enrolled in play-oriented preschools are more socially adjusted later in life – and less likely to commit a felony or be suspended from work – than are kids who attended play-free preschools where they were constantly instructed by teachers.

A 2003 study even suggests that play promotes emotional and social development in animals. Researchers allowed thirteen control rats to play freely with companions for three and a half days, and kept fourteen others isolated for the same period. Examination revealed that the brains of the rats which had played contained much higher levels of BDNF – a protein that stimulates the growth of new neurons – than those of the animals that had not. “I think play is the major mechanism whereby higher regions of the brain get socialized,” says neuroscientist Jaak Panksepp, who co-authored the study.

E Research also suggests that imaginative play is critical for children’s emotional health, as it enables them to work through anxiety. In a 1984 study, researchers assessed the anxiety levels of seventy-four children on their first day of preschool. They labeled each child as either ‘anxious’ or ‘not anxious’, then randomly split the kids into groups. Half were escorted to rooms full of toys, where they played for 15 minutes; the other half listened to a teacher tell a story for 15 minutes. Afterward, the levels were assessed again. The anxiety levels of the anxious kids who had played had dropped by more than twice as much compared with the anxious kids who had listened to the story.

F Results of animal studies support these views. In 2008, neuroscientist Stephen Siviy put rats into a chamber and exposed them to a collar previously worn by a cat, making them visibly anxious. Later, the chamber was cleaned to remove the cat odor, and the rats were put back without the collar. They immediately became anxious again, probably because they associated the space with the cat. The researchers then introduced another rat – one that had never been exposed to the collar and was not afraid – and it began playing with one of the rats. “Shortly thereafter, the first rat relaxed and became calm,” says Siviy, “suggesting that play helped lessen its anxiety.”

G Play even appears to make kids smarter. In a classic study, researchers told a group of preschool children to play freely with some common objects such as paper towels, a screwdriver, a wooden board and paper clips. Another group was asked to imitate an experimenter using the objects in common ways. A third set was told to sit and draw whatever they wanted, without seeing the objects. After 10 minutes, the researchers asked the children to come up with ideas for how one of the objects could be used. The kids who had played with the objects named, on average, three times as many nonstandard, creative uses for the objects than those in either of the other two groups did, suggesting that play fosters imaginative thinking.

A later animal study produced similar results. Experimenters isolated young rats during the development period when they would have most frequently played. The researchers taught these rats, and a group that had been allowed to play without constraints, to pull a rubber ball out of the way to get a food treat. A few days later they switched the setup so the rats would have to push the same ball to get the treat. Compared with the isolated rats, the ones which had played proved to be far more adept at solving problems. “Play is like a kaleidoscope,” says evolutionary biologist Marc Bekoff, “in that it is random and creative. It encourages flexibility and creativity that may, in the future, be advantageous in unexpected situations or new environments. And in the absence of play, children miss vital learning experiences.”

One of the most serious problems facing Australian farmers is an increase in the salt content in the soil. However, there are new weapons emerging in the fight against salinity.

A Beneath the flat, impassive surface of Australia lie hidden mountains, valleys and gorges – ancient traps and channels for the deadly salt that is stealthily killing so much of the Australian landscape. The war on salt is calling forth new weapons. A suite of high technologies used by geologists to see underground and prospect for gold and minerals is now being used to pinpoint the presence of salt beneath the landscape, and predict where it might move.

B Unless this process is clearly understood, warns Chief of Exploration and Mining Dr Neil Phillips, the hard work now underway of planning and tree-planting on the surface may be rendered ineffective: salt can still sneak past and erupt, following one of the ancient river channels formed millions of years ago. The use of airborne electromagnetics to detect salt hidden beneath the landscape has been around for a decade, but the past two years have seen a major development in its precision and powers of detection. Like the use of radar in battles, it has the potential to turn the tide of the struggle in favour of the defence by helping to pinpoint, plot and predict the movements of the foe.

C Angus Howell, who farms near Warrenbayne, in Southeast Australia, saw his first outbreak of salt in 1948. Over the ensuing decades the patches spread and multiplied until they consumed almost 100 hectares. By the late 1970s, Howell and his fellow farmers had decided it was time for action and established a government-funded ‘Landcare’ group in a bid to save Australia’s farmland. But despite a mounting effort by scientists, farmers and governments, the ‘white death’ continued to encroach. Small successes were eclipsed by larger defeats and fresh outbreaks.

D ‘The technical solutions just aren’t there yet for dealing with broadacre salinity, nor are the social and economic solutions. How do you introduce the land-use changes that are needed when people still need to make a living?’ Howell asks. There is no satisfactory solution yet. Part of the problem has lain in salt’s ability to mount ambushes, emerging somewhere new, sometimes unexpected and unexplained, beating plans to intercept it. Only now are scientists starting to really disclose its secret subterranean stores and passages.

E The need for such knowledge is pressing. Salt has already afflicted six million hectares of once-productive country. At present rates it is predicted that, by 2050, it will have sterilised a total of 17 million hectares and the waters of Australia’s Murray River will regularly exceed the World Health Organisation’s salt limits for drinking water. Defeating this assault may take centuries, not decades.

F Electromagnetic surveys measure the electrical conductivity of soil to reveal the distribution of salt and the nature and variability of the regolith – the weathered rock and sediment that may lie above the bedrock. Magnetic surveys measure small differences in the Earth’s magnetic field, enabling scientists to probe the deep past and reconstruct ancient landscapes – rivers, basins and faults now buried under tens of metres of sediments. These features help to reveal where groundwater is stored, dictate the direction of groundwater movement, and are critical to predicting or ruling out salinity hot-spots.

G Radiometric analysis is based on the detection of radiation emitted by elements contained in rocks and soils, allowing scientists to delineate landforms. These factors influence the mobility of salt through the soil profile and help determine where to plant particular crop species to tackle the problem.

Using data from the Murray River region, scientists have revealed a network of ancient drainage channels buried metres beneath the current landscape. These buried channels may carry salt and sometimes run at right angles to channels on the surface. This implies that the salt could move underground in quite a different direction to what one would expect by looking at surface slope and drainage.

H One of the biggest advances in detection, says Professor Neil Phillips, has come with the integration of different techniques such as magnetics, electromagnetics and radiomagnetics, and ground mapping. Individually, these technologies only gave clues to what was going on underground. Together they provide a far more revealing picture of the subsurface landscape, several hundred metres deep. Advanced airborne electromagnetics, in particular, enables scientists to take ‘slices’ of the landscape at depths of five metres, ten metres, fifteen metres and so on, to determine where salt may be stored at depth. This is building up a four-dimensional picture of the subsurface landscape, enabling researchers to understand movements of salt in width, depth, breadth and time.

From such technologies it will be possible to locate salt stores, identify how saline they are, look at man-made and natural changes to the landscape that may cause it to mobilise, and then predict where it will head to and over what time span. This in turn will give the salt warriors time to model various ways of containing or curbing the menace, see what works best and then try it out on the ground.