Ever wondered why your mind weirdly starts reading English subtitles on an English film, automatically, without your being able to stop it? The answer lies in neuroscience, of course, but this feature of the brain is the key to a literacy project that has benefited more than 200 million Indians.
The subtitling project, PlanetRead, has turned India's national pastime of singing along to Bollywood film songs into a powerful tool to help the "notionally literate" poor to read. In India anyone who can sign their name - even partially - is considered literate.
By regularly watching programs with subtitles in the language they speak, millions of people with weak reading skills get reading practice. Over time, their reading improves imperceptibly, enabling them to read newspapers, fill out forms, and try for better jobs.
The idea is the brainchild of Dr Brij Kothari, a 49-year-old professor at the Indian Institute of Management in Ahmedabad. He realised that, with the simple addition of subtitles to Bollywood's prolific output, barely literate Indians would instinctively read the lyrics of the songs they watched on television.
The idea first occurred to him when he was trying to learn Spanish by watching Spanish films. If the subtitles had been in Spanish rather than in English, he used to think, his Spanish would improve.
He persuaded the national broadcaster, Doordarshan, to put Hindi subtitles on Hindi films. "The beauty is that viewers don't have to do anything. They just watch television, as they do anyway. They are not even aware that they are benefiting in any way. Then, one fine day, they realise they can read," said Kothari.
Tall, lanky and bearded, Kothari looks like the genial professor that he is. But his persistence with the PlanetRead project - launched 17 years ago - and its colossal impact won him the US Library of Congress' International Literacy Award last month.
Kothari believes his project won the award because of PlanetRead's scale. In India, scale is everything. Unless a project touches millions, it is a mere speck. Even the film industry operates on a gargantuan scale. Bollywood churns out 1000 films a year, more than any other film industry.
Hundreds of millions of Indian viewers watch channels that endlessly replay hit movies because their appetite for film songs is insatiable. Currently, more than 200 million viewers watch subtitled songs as part of the project.
Kothari is now trying to persuade the government to have a broadcasting policy that puts subtitles on all songs on television, in all 22 official languages. That way, he will be able to reach out to about 700 million viewers.
The government appears responsive to his request thanks to independent studies that have shown that three to five years' exposure to same-language subtitling can enable a person familiar with the alphabet to become functionally literate.
Before exposure to subtitles, only 34 per cent of people surveyed could read a newspaper. After, 70 per cent could read a newspaper.
Mithul Palwankar, a 19-year-old coconut seller in Ahmedabad, speaks Gujarati, but has become bilingual after reading Hindi subtitles. "The subtitled songs have improved my Hindi reading and speaking skills. I have learnt new words and can read more fluently."
The project does not make weak readers great readers in just a few months, says Kothari, but it does transform millions of budding readers into functional readers.
"Reading subtitles is automatic and inescapable. The key is for the word to match the audio. Neuroscience has proved that what fires together, wires together, so when the audio and words start firing together, the two fuse in the mind," says Kothari.
He told friends that if Hindi subtitles were put on Hindi movies, India would become literate. Everyone said it was too simple. Had it been so easy and effective, someone must already have thought of it, surely? But no one had.
Officially, 73 per cent of India's 1.2 billion-strong population is literate, according to 2011 data. But the figure is misleading in that, for half of them, "literate" is a misnomer because they cannot read a newspaper headline.
All "literate" means is that they can sign their name. Studies show that a large percentage cannot even do this, or can only partially sign their name. It is these weak readers that Kothari targets.
While the Indian government reflects on his request to expand the program, a member of his team has just left for Kabul to explain the concept to the Afghan government.
"In a country where girls and women are prevented from going out, the mere fact of improving their literacy through sitting at home and watching television is appealing - even the Taliban can't stop that," said Kothari.