BRIGHT lights, big cities. Or are they? All is not as it seems in this stunning photo snapped from the International Space Station.

The mass of white lights to the east shows Thailand’s capital Bangkok, its city streets abuzz with nocturnal activity. But the green lights dotted to the south of the city, in the Gulf of Thailand, and to the west, in the Andaman Sea, are something rather different.

These lights reveal the position of many hundreds of fishing boats, which use huge banks of green LED lights to attract plankton and small fish to the sea surface. The lured fish act as attractive bait for the prime target – squid.

To the right of Bangkok’s bright sprawl is a far smaller patch of light: Cambodia’s capital, Phnom Penh. The difference in night-time light illustrates the sharp contrast between the two nations. Cambodia is far more rural, with fewer big urban areas than its neighbour.

For the eagle-eyed, there’s a bonus item to spot. The black bar across the south of the Andaman Sea is actually the ISS’s robotic arm doing its best to photobomb the image.

Photography
NASA/JSC

This article appeared in print under the headline “All that glitters”

Elliot Freeman was a student when he first noticed something strange. Looking out into the dark one evening he spotted a distant lighthouse flashing a Morse code signal. “Every time I saw the flash I heard a distinct buzzing sound,” he says. None of his friends could hear anything. “I thought ‘yeah, that’s kind of odd’. I should look into that some time.”

It turns out Freeman is not alone. He is one of a group of people who experience a strange phenomenon called visually-evoked auditory response (vEAR): they hear noises when they see certain silent moving images. Now he has carried out the biggest study of the condition so far and found that as many as one fifth of us might experience this too.

This could explain the popularity of a that give some people the sensation of sound. The noisyGIFs subreddit has almost 100,000 subscribers, and last year an animated became a viral hit on Twitter. Many people said they could hear a sound when the jumping pylon landed. “It raised everyone’s awareness above a threshold where it was taken more seriously,” says Freeman. “People were suddenly aware of it.”

Does anyone in visual perception know why you can hear this gif?

— Lisa DeBruine ️‍ (@lisadebruine)

, who is now a psychologist at City University of London, worked with his colleague Christopher Fassnidge to recruit people to an online survey that tests for vEAR (you can ). The test involved questions about synaesthesia, and watching 24 silent videos and rating them for vEAR sounds.

Around 22 per cent of the 4000 people who did the survey rated more than half the videos as stimulating clear and noticeable sound responses. This seems to agree with much smaller previous studies by other researchers, which have found that about 20 per cent of people experience this phenomenon.

Further work with 1000 of the survey respondents revealed that people who experience vEAR are more likely to feel the reverse effect too: they see flashes of light in the dark when they hear certain noises. They were also more likely to get earworms – songs that get stuck in your head.

Most of the people who experience vEAR were more likely to get it when it was easy to imagine an accompanying sound – such as a hammer hitting a nail, or a screaming face. But a smaller group of people seemed to experience vEAR as a direct response to motion and movements within a GIF, including in more abstract, changing patterns.

The results add to the debate about this and other types of synaesthesia: does it come from unusual connections in the brain, or is it the result of heightened brain activity? Freeman speculates that some people may have more crosstalk between the auditory and visual parts of the brain, but that this is more actively suppressed in others. He is now experimenting with brain stimulation, to see if he can remove the inhibition of this crosstalk.

, at Lausanne University Hospital, Switzerland, was one of the first people to study vEAR. She says Freeman’s survey suggests that the condition is on a spectrum, with some people experiencing more cross-talk between sensory brain areas than others. “It’s important for people who experience this phenomenon to understand that it’s not all that unusual,” she adds. “It’s often reassuring to know that!”

“Drones will be able to monitor the building site from the air and constantly update the plans”