The experiment is a pro bono safety project conceived by a Mumbai-based “behavior architecture” consultancy named Final Mile, which uses the lessons of cognitive psychology to influence people on the brink of making decisions. Classical economics has long held that human beings are largely rational, even as a century’s worth of psychological study has suggested otherwise. Advertisers and marketers have crafted campaigns on the premise of the rational being, believing that, say, a detergent brand need only insist on how much cleaner it can clean. But recent studies in behavioral economics and cognitive neuroscience have emphasized that human decisions are fraught with irrationality — that a detergent buyer may be more influenced by the shape of the container, or where it is stocked in the store.

This modest tinkering has had dramatic results. In the six months before the experiment went live in December 2009, Wadala had recorded 23 track-crossing deaths, said M. C. Chauhan, a manager with the Central Railway’s Mumbai division. Between January and June 2010, that number had dropped to nine; in the next eight months, up until February 2011, only one death was registered. “We think the project is a huge success,” Chauhan said.

For just over a year, however, an experiment at Wadala station, on the Harbour Line, has been hinting at unorthodox solutions to this problem. On the surface, the experiment involves small, odd changes. Certain railway ties have been painted bright yellow; a new kind of signboard has been installed near the tracks; engine drivers have modified the way they hoot their warning whistles.

The consequences are often fatal. On average, 10 people die daily by being hit as they’re crossing the tracks. Track trespassing is the largest everyday cause of unnatural deaths in Mumbai.

Every mile of this network runs through dense pockets of population, houses, and buildings; these are often just yards away from the tracks, separated at best by a low wall. Sixty percent of the length of the Central Line, for instance, has slums on either side. At rush hour, trains barrel through every couple of minutes, and pedestrian bridges over the tracks are rare. As a consequence, the most popular way for pedestrians to get between east and west Mumbai is to dash illegally over unguarded sections of the tracks.

The suburban rail system in the Indian megalopolis of Mumbai is best visualized as two slim arteries cutting through a crowded peninsula. On a map, the Western Line runs due north; the Central Line begins similarly, then wanders away into the city’s northeastern parts. These two lines and a couple of adjunct capillaries, making up a rail network dating back to 1857, carry roughly 7 million commuters a day, some of them over distances as long as 75 miles.

First, Final Mile painted alternate sets of railway ties in fluorescent yellow — five painted, five unpainted, and so on — to tackle what is known as the Leibowitz Hypothesis. As laid out in a 1985 issue of American Scientist by experimental psychologist Herschel W. Leibowitz, the hypothesis found that we frequently underestimate the speed at which large objects move. Leibowitz, who died earlier this year, first observed this with aircraft, and in 2003, a pair of scientists proved the hypothesis for trains. “The misperception happens because the brain has no frame of reference, no way to evaluate roughly how fast a train is moving,” said Satish Krishnamurthy, a Final Mile behavior architect. But with the new paint job, Krishnamurthy said, “the mind now has a way to gauge the train’s speed, by observing how fast it traverses these ties.”

To walk around the Wadala experiment is to understand the surprising effectiveness of simple appeals to the human mind’s irrationality. Before the experiment began, the few exhortations to trespassers consisted of warning signs with lengthy text and stick-figure diagrams. These had proved tragically inadequate, so Final Mile designed three specific “interventions,” each intended to tackle a particular cognitive problem.

Final Mile tries to translate insights from cognitive neuroscience into subliminal marketing strategies. (As the company’s website loads, the screen shows a figure strolling from one brain hemisphere, labeled “Awareness,” to another, “Action.”) Consulting for a large e-commerce portal, for example, Final Mile advised that a screen of search results not throw up too many products. This drew upon the research of Sheena Iyengar, a Columbia Business School professor who discovered that too much choice overwhelms consumers, prompting them not to buy anything at all. “The work we do questions some traditional marketing theories,” said Biju Dominic, the CEO of Final Mile. “A lot of people think you can just bypass the irrational elements of decision-making. But you can’t.”

In the past, safety campaigns, appealing to our rational minds through such measures as cautionary signs printed with text, have stumbled on a cognitive hurdle. The conscious human mind has evolved to latch first on to new information, and while this enables us to process the world around us more swiftly, it also means that familiarity breeds inattention. A sign printed “Caution,” then, has far less impact the 10th time we see it. But behavioral theorists place more faith in the subconscious mind, which is an indiscriminating filter of all input, whether old or new.

These precepts about how to sway people have begun to filter into crowd-control situations, financial education programs, and even the apparatus of government. But these tactics can also be repurposed to save lives. The Mumbai experiment provides a concrete new example of how seemingly abstract principles of irrational decision-making can, quite literally, steer human beings to safety.

Second, the consultants replaced the stick-figure signboards with a graphic three-part tableau, featuring in extreme close-up the horror-struck face of a man being plowed down by a locomotive. “We hired an actor,” Krishnamurthy said, smiling, “because it had to be realistic.” They were drawing on the research of Joseph LeDoux, a New York University professor of neuroscience and psychology. LeDoux studies the links between emotion and memory, and in particular the mechanism of fear. “Emotional memory is stored in the nonconscious part of your brain,” Dominic said. “If you’ve been in a car crash and, months later, you hear tires squealing, your heart rate goes up and you start to sweat. That’s because your emotional memory has been stirred up.” The new signs dispense with explanatory text and instead attempt to trigger an emotional memory of fear.

Final Mile’s third intervention required train drivers to switch from one long warning whistle to two short, sharp blasts. By way of explanation, Dominic cited a 2007 paper from the Stanford University School of Medicine, which found that brain activity — and hence alertness — peaks during short silences between two musical notes. “The silence sets up a kind of expectation in the brain,” said Vinod Menon, the paper’s senior author and a behavioral scientist working with the Stanford Cognitive and Systems Neuroscience Lab. “That’s the way it works in music, and it isn’t inconceivable that it would work similarly with train whistles.”

These simple, inexpensive interventions have worked so well that they’re now being extended across the length of the Central Line. But the larger implications of the experiment stretch beyond Mumbai, and beyond track-crossing deaths as well.

India is not the only country with a track safety problem. The very nature of railroads — tracks stretching many hundreds of miles, often into rural territory — has meant that the trespassing problem is difficult to solve. In the United States, the number of pedestrians who were fatally hit by trains rose 8 percent from 2009 to 2010, according to the Federal Railroad Administration Office of Safety Analysis. California, Florida, and Illinois rank at the top of the fatality data set; the Massachusetts Bay Transportation Authority, by comparison, fares well. In California in 2010, 66 people died after being hit by trains; the MBTA’s corresponding figure is only 2.

Transit authorities, as well as organizations like Operation Lifesaver, an energetic nonprofit born in Idaho in 1972, have found some success in preventing accidents through such traditional, “rational brain” methods as textual billboards and public awareness campaigns. Operation Lifesaver helped achieve a remarkable 84 percent decline in car-train collisions between 1972 and 2009. But pedestrian deaths have proven harder to reduce. “We haven’t always been able to break through,” said Marmie Edwards, a vice president with Operation Lifesaver. “We don’t have behavioral people yet, and I think now that has to be on the continuing agenda.”

Outside of transit, health and safety officials have similarly explored communication methods that appeal to the subconscious. A three-year study in Europe examined how nutrition labels could be more effective by targeting subconscious perception. Canadian cigarette packs now carry graphic images of blackened lungs, instead of a cartoonish skull-and-crossbones.

Humans are still human, and none of these tactics prevent unnecessary deaths completely. Both in India and in the United States, there is a tacit acceptance that illegal crossings cannot be wholly stopped. But protecting trespassers is often just a matter of getting them to notice the world more acutely, to pause for that extra second before crossing. Tapping into human cognition patterns offers a powerful way to break through. “Part of the issue we have is that this is habitual behavior, and it’s seen as not having any serious or enduring consequence,” says Warren Flatau, a senior public affairs officer with the Federal Railroad Administration. “We have to drive home the awareness that it doesn’t matter if it’s the first or the ten thousandth time you’re crossing the tracks — there’s still the possibility that you’ll be hit.”

Samanth Subramanian is the Indian correspondent for The National. His first book, a collection of reported essays titled ”Following Fish: Travels around the Indian Coast,” was published by Penguin Books in May 2010.

Correction: Because of a reporting error, an earlier version of this article about railway signs in Mumbai misidentified the rail line that Wadala station lies on. It is on the Harbour Line.

© Copyright 2011 Globe Newspaper Company.