A new study shows the brain needs up to 15 seconds to process the images it receives, so it shows us the ones it had stored.
It may seem strange, but the present is impossible to observe. When we look at something, or someone, we do not see it as it is at the present moment, but with a time lag that increases with distance, so that the further we are from what we are looking at, the further back we see it in the future. weather. This is so for the simple reason that the speed of light is not infinite, but it takes time to travel any distance, no matter how small.
So when we look at something, what we actually see are photons of light reflecting off subjects and people, traveling to our retina and producing a stimulus that creates images in our brain.
And we see things not as they are now, but as they were when those photons began their journey toward us. For objects or people in our environment, the time difference is minimal, just a few billionths of a second, but if we look at distant stars, or galaxies, that time difference increases to thousands, millions or, for more distant objects, even billions of years.
Our brain is ‘too slow’
It is a simple matter of physics, but now a new study carried out by researchers at the University of California at Berkeley has just dealt a new and severe blow to our definition of reality, confirming that what we see is nothing more than an illusion of the past.
And it is that our brain is “too slow” to process in real time the enormous amount of visual stimuli that it continuously receives, so that it does not show us the last image in real time, but rather an earlier version of it. Its update time, as explained by scientists in ‘Science Advances‘it is neither more nor less than 15 seconds.
The work adds to the growing body of studies on the mechanism behind the so-called ‘continuity field‘, a perceptual function in which our brain fuses what it sees constantly to give us a sense of visual stability. In the words of David Whitney, study co-author, “If our brains were always updating in real time, the world would be an irritating place, with constant fluctuations of shadows, lights and movement, and we would feel like we were hallucinating all the time”.
But instead, explains the lead author of the research, Mauro Manassi, “Our brain is like a time machine. Keep sending us back in time. It’s like we have an app that consolidates our visual input every 15 seconds into an impression so we can handle everyday life.”.
The ‘change blindness’
For their work, Manassi and Whitney studied a brain mechanism called “change blindness,” which makes us unaware of subtle changes that occur over time, such as the difference between an actor and his double in some scenes in a movie. To this end, the researchers recruited 100 volunteers and asked them to carefully observe faces that were changing age or gender in 30 second videos. The images did not include the head or facial hair. Only eyes, eyebrows, nose, mouth, chin and cheeks, so there were few clues, such as thinning hair, about the age of the faces at any given time.
Each participant was then asked to identify the face they had seen in the video, with virtually all choosing a frame they had seen towards the middle of the sequence, rather than the one at the end, which would have been the most up-to-date image.
“It could be said Whitney explains. that our brain is procrastinating. It’s too much work to constantly update the images, so you stick to the past because the past is a good predictor of the present. We recycle information from the past because it is faster, more efficient and requires less work». In fact, the results suggest that the brain works with a slight delay of 15 seconds when processing visual stimuli. This has both positive and negative implications.
Delay prevents us from feeling bombarded by visual information in everyday life
“The delay Manassi explains. It’s great for keeping us from being bombarded by visual information in everyday life, but it can also have life-or-death consequences when surgical precision is needed. For example, radiologists detect tumors and surgeons must be able to see what is in front of them in real time; if their brains are wired to what they saw less than a minute ago, they might be missing something.”.
Despite this, the misleading ‘continuity field’ created by the brain, the researchers explain, is an intentional function of consciousness. We are not literally blind Whitney concludes. It’s just that our visual system’s slowness to update itself can make us blind to immediate changes because it clings to our first impression and pushes us back into the past. Ultimately, though, the continuity field supports our experience of a stable world.”.
Font: Jose Manuel Nieves / ABC
Reference article: https://www.abc.es/ciencia/abci-solo-vemos-pasdo-nuestro-cerebro-no-procesa-imagenes-tiempo-real-202203080121_noticia.html#ancla_comentarios
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