The Man Who Hears People Before They Speak
2013 07 08

By Helen Thomson | NewScientist



"I told my daughter her living room TV was out of sync. Then I noticed the kitchen telly was also dubbed badly. Suddenly I noticed that her voice was out of sync too. It wasn’t the TV, it was me."

Ever watched an old movie, only for the sound to go out of sync with the action? Now imagine every voice you hear sounds similarly off-kilter – even your own. That’s the world PH lives in. Soon after surgery for a heart problem, he began to notice that something wasn’t quite right.


"I was staying with my daughter and they like to have the television on in their house. I turned to my daughter and said ’you ought to get a decent telly, one where the sound and programme are synchronised’. I gave a little chuckle. But they said ’there’s nothing wrong with the TV’."

Puzzled, he went to the kitchen to make a cup of tea. "They’ve got another telly up on the wall and it was the same. I went into the lounge and I said to her ’hey you’ve got two TVs that need sorting!’."

That was when he started to notice that his daughter’s speech was out of time with her lip movements too. "It wasn’t the TV, it was me. It was happening in real life."

PH is the first confirmed case of someone who hears people speak before registering the movement of their lips. His situation is giving unique insights into how our brains unify what we hear and see.

It’s unclear why PH’s problem started when it did – but it may have had something to do with having acute pericarditis, inflammation of the sac around the heart, or the surgery he had to treat it.

Brain scans after the timing problems appeared showed two lesions in areas thought to play a role in hearing, timing and movement. "Where these came from is anyone’s guess," says PH. "They may have been there all my life or as a result of being in intensive care."

Disconcerting delay

Several weeks later, PH realised that it wasn’t just other people who were out of sync: when he spoke, he registered his words before he felt his jaw make the movement. "It felt like a significant delay, it sort of snuck up on me. It was very disconcerting. At the time I didn’t know whether the delay was going to get bigger, but it seems to have stuck at about a quarter of a second."

Light and sound travel at different speeds, so when someone speaks, visual and auditory inputs arrive at our eyes and ears at different times. The signals are then processed at different rates in the brain. Despite this, we normally perceive the events as happening simultaneously – but how the brain achieves this is unclear.

To investigate PH’s situation, Elliot Freeman at City University London and colleagues performed a temporal order judgement test. PH was shown clips of people talking and was asked whether the voice came before or after the lip movements. Sure enough, he said it came before, and to perceive them as synchronous the team had to play the voice about 200 milliseconds later than the lip movements.

The team then carried out a second, more objective test based on the McGurk illusion. This involves listening to one syllable while watching someone mouth another; the combination makes you perceive a third syllable.

Since PH hears people speaking before he sees their lips move, the team expected the illusion to work when they delayed the voice. So they were surprised to get the opposite result: presenting the voice 200 ms earlier than the lip movements triggered the illusion, suggesting that his brain was processing the sight before the sound in this particular task.

And it wasn’t only PH who gave these results. When 37 others were tested on both tasks, many showed a similar pattern, though none of the mismatches were noticeable in everyday life.

Many clocks

Freeman says this implies that the same event in the outside world is perceived by different parts of your brain as happening at different times. This suggests that, rather than one unified "now", there are many clocks in the brain – two of which showed up in the tasks – and that all the clocks measure their individual "nows" relative to their average.

[...]

Read the full article at: newscientist.com




Related Articles
Decoding Space and Time in the Brain
"Laws of Physics for a Holographic Universe" --New Theories of Space-Time
The Brain’s Stopwatch – Emotions and Time Perception
Why Time is a Social Construct
Mind reading Sharjah Girl ‘exceedingly rare’ savant
Fractal Minds and the Sacred Cosmology : Neuroscience & Psychology meets Esoteric Religion


Latest News from our Front Page

Tiny Micro Robots Build Things in ‘Microfactory’
2014 04 17
The teenie-weeniest robot uprising ever might be sooner rather than later due to the work of research institute SRI. Don’t let these microbots’ size fool you, there is power in numbers and thousands of the robots can work together to perform tasks at dizzying speed. From ReCode.net: SRI International has developed a new generation of ant-like robots that can work as ...
’We are not dead yet’: Heartbreaking text messages sent from schoolchildren trapped aboard South Korean ferry
2014 04 17
Passengers on board the South Korean ferry sent heartbreaking messages to their family members just moments before it sank. Children waiting to be rescued frantically reached for their phones as the boat began to list in a bid to communicate with their loved ones a final time. Twenty-four people, including five students and two teachers, have been found dead, but 272 are ...
"A world of pure imagination": How Occupy turned to "anarchy"
2014 04 17
In the closing ceremonies of London’s 2012 Summer Olympics, comedian Russell Brand, perched atop the Beatles’ "Magical Mystery Tour" bus, opened his performance by singing the first lines of "Pure Imagination" from the movie Willy Wonka: Come with me And you’ll be In a world of Pure imagination ...
Artists ’have structurally different brains’
2014 04 17
Artists have structurally different brains compared with non-artists, a study has found. Participants’ brain scans revealed that artists had increased neural matter in areas relating to fine motor movements and visual imagery. The research, published in NeuroImage, suggests that an artist’s talent could be innate. But training and environmental upbringing also play crucial roles in their ability, the authors report. As in many areas ...
NSA-proof email service goes online
2014 04 17
A new email service that protects its users from the prying eyes of the NSA and other spy agencies has gone online. The service’s creators say it will make encrypted messaging accessible to all and curtail internet snooping. Germany-based Lavaboom was inspired by Lavabit, the encrypted email service that was believed to have been used by whistleblower Edward Snowden before it ...
More News »