If you've ever seen those annoying lip-sync errors on TV when the video doesn't quite match up to the sound, did you also realise that your brain eventually adjusts the signal to improve your experience?
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(The story was first published in Horizon Magazine)
In fact, our brains tidy up the signals we receive from the external environment all the time to make our experience of the present more plausible than it really is, according to researchers looking into how we understand what is ‘now’.
The research is part of a series of projects looking at how we process time in the brain and use information we receive to predict future events.
Professor Virginie van Wassenhove, a neuroscientist at CEA Saclay in France, runs the MINDTIME project, funded by the EU's European Research Council (ERC), which is trying to decode our mental representation of time.
She and her team performed an experiment whereby they simplified the lip-synch effect into a series of flashes and beeps going off every second.
These stimulated an oscillating response of activity in the brain at the same frequency, which the researchers measured using a helmet sensitive to fast-changing magnetic signals in the brain. They found that, if the flashes and the beeps are desynchronised, the brain quickly recalibrates its response to make the audio and visual inputs simultaneous.
This flexibility of the brain means that we are continually adjusting and constructing our experience of ‘now’. To some extent, 'the present' is a bendy, flexible entity that our brains choose depending on what we are seeing or hearing.
‘I’m super excited about this,’ said Prof. van Wassenhove. ‘That the brain has the capacity to recalibrate its timing - that's very powerful. It means that the brain can change the simultaneity of events in the world to make our experience more plausible.’
The researchers are investigating whereabouts in our brains our concept of time lies. In the same way that we have a neural code for seeing the colour 'red', with this property coded in our neurons to represent the physical world, we must also have cognitive neural code for thinking about and experiencing time as an intelligible awareness.
‘Timing is everywhere, so when we study timing we are looking at the foundation of neural codes,’ said Prof. van Wassenhove. ‘Without good temporal mechanisms you’re not going to be able to plan a future for yourself, so it has huge implications.’
Preparing for the future, at least in terms of immediate events, is something we are quite good at doing without any conscious effort. In Italy, another group of researchers has been investigating how the brain sorts through patterns of events to come up with predictions of what will happen next in the general environment we are in, a process known as statistical learning.
‘This could allow us to notice something as mundane as the leaves blowing in a different direction,’ says Professor Uri Hasson from the University of Trento, who is investigating statistical learning and prediction in the brain as part of the ERC-funded NEUROINT project.
Prof. Hasson and his team are interested in finding out what sort of short-timescale, repetitive patterns our brains are able to pick up on and use to predict the future without us having to actually calculate percentages or probabilities.
They have found that some parts of our brains are less active or less connected when presented with either completely random information or simple, regular patterns - which could be caused by something like a dripping tap - but spring into action when faced with more complex patterns - this could equate to something like a mouse rustling in a bag.
Focusing our attention on patterns that are complex but not too random means that we can quickly analyse new environments at a fairly abstract level and compress the information, improving efficiency.
'This is one of the most interesting results of our research program,' says Prof. Hasson.