Our brain keeps us 15 seconds “in the past” to help us see a stable perception of the world

(ORDO NEWS) — Our eyes are constantly being bombarded with vast amounts of visual information – millions of shapes, colors and ever-changing motion all around us. For the brain, this is not an easy task.

On the one hand, the visual world is constantly changing due to changing lighting, point of view, and other factors. On the other hand, our visual data is constantly changing due to blinking and the fact that our eyes, head and body are often in motion.

To get an idea of ​​the “noisiness” of this visual signal, place your phone in front of your eyes and record a live video while you walk and look at different objects.

A messy, messy result is exactly what your brain is dealing with at every moment of your visual perception.This can be seen in the video below as well. The white circle on the right shows potential eye movements, and the blur on the left is the jumpy visual stream at any given time.

However, vision never seems like a job to us. Instead of perceiving fluctuations and visual noise that can be captured on video, we perceive a consistently stable environment.How does our brain create this illusion of stability? This process has fascinated scientists for centuries and is one of the fundamental questions of vision science.

The brain of a time machine

In our latest research, we have discovered a new mechanism that, among other things, may explain this illusory stability.

The brain automatically smoothes our visual data over time. Instead of analyzing each individual visual snapshot, we currently perceive the average of what we have seen over the past 15 seconds. Thus, by arranging objects together to make them appear more similar to each other, our brain tricks us into perceiving a stable environment.

Living “in the past” may explain why we don’t notice the subtle changes that occur over time.In other words, the brain is like a time machine that constantly sends us into the past. It’s like an app that merges our visual data into a single impression every 15 seconds so we can deal with everyday life.

If our brains were constantly updating information in real time, the world would seem like a chaotic place with constant fluctuations in light, shadow and movement. It would seem to us that we are hallucinating all the time.We have created an illusion to illustrate how this stabilization mechanism works.

Looking at the video below, the face on the left slowly ages over the course of 30 seconds, and yet it is very difficult to notice the full extent of the age change. In fact, observers perceive the face as aging more slowly than it really is.

To test this illusion, we recruited hundreds of participants and asked them to view close-ups of faces chronologically changing their age in 30-second videos.When asked to name the age of the face at the very end of the video, participants almost always gave the age of the face that was presented 15 seconds before.

When watching a video, we constantly focus on the past, so the brain constantly refers us to the previous 10-15 seconds (when the face was younger).

Instead of seeing the latest image in real time, people actually see earlier versions because the image update time in our brain is about 15 seconds. Thus, this illusion demonstrates that visual smoothing over time can help stabilize perception.

Essentially, the brain is procrastinating. It’s too much work to constantly process every image taken, so the brain sticks to the past, because the past is a good predictor of the present.In essence, we process information from the past because it is more efficient, faster, and requires less effort.

This idea – which is supported by other results – about the mechanisms in the brain that constantly shift our visual perception towards past visual experiences is known as continuity fields.

Our visual system sometimes sacrifices accuracy for a smooth visual experience of the world around us. This may explain why, for example, when watching a movie, we don’t notice subtle changes that occur over time, such as the difference between actors and their stunt counterparts.

Consequences

There are positive and negative consequences of our brain having a slight delay in processing the visual world. This delay is good for keeping us from feeling like the victims of daily visual bombardment, but it can also be fraught with life-and-death consequences when absolute accuracy is required.

For example, radiologists examine hundreds of images by viewing several related images one after the other. When reviewing an x-ray, clinicians are usually asked to look for any abnormalities and then classify them.

In the course of this visual search and recognition task, researchers have found that radiologists’ decisions are based not only on the current image, but also on images they have seen before, which can have serious consequences for patients.

The slowness of our visual system to update can make us blind to immediate change because it clings to first impressions and drags us into the past.

Ultimately, however, continuity fields contribute to our perception of a stable world. At the same time, it is important to remember that the judgments we make every day are not entirely based on the present, but are heavily influenced by what we have seen in the past. The Conversation

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