New Research Detects Fluctuations in Sensory Perception
등록일 2019년 01월 07일 수요일
수정일 2017년 11월 22일 수요일

Photo by: Steve Snodgrass via Flickr

Our perception of the world around us is never as accurate as we always think it is.This new finding was deduced from a research facilitated by the collaboration of the University of Sydney, University of Florence and the University of Pisa.The study suggests that our attention and perception are always in a constant fluctuation of a rhythmic flow.

For years, it has been known that sight perception in human beings is cyclical.You could say that our eyes play tricks on us.But could it also mean that other senses play tricks on us as well?The research sought to find out whether the same is true for any other sense perception.In a simple experiment using weak sounds, the researchers were able to show that our sound perception behaved similarly.There seems to be a rhythmic oscillation or rather fluctuation of perception.

They observed and inferred that (i) peak perception for sound keeps alternating between the ears.This suggests that auditory perception keeps oscillating as well. (ii) Decision-making based on auditory perception also oscillates since it is directly affected by perception. (iii) Oscillations are a key feature of all sensory perception and not restricted to sight only.

Professor David Alais of the University of Sydney schools of Psychology and Medical Science, a lead researcher in the study, explained that these new findings of auditory perception and our perception in general, support the theory that perception is not passive.It is our conscious interpretation of how we intercept senses, that we understand the world around us.If our senses are in fluctuation, then our understanding of the world around us falls on those cycles too.

"We have suspected for some time that the senses are not constant but are processed via cyclical, or rhythmic functions; these findings lend new weight to that theory," Prof Alais added.

These auditory cycles were observed to fluctuate at about six cycles in one second.This may seem very fast, but considering that the brain can make oscillations of about 100 times in just one second, it is actually slow.Moreover, these figures prove to be very important once the understanding that human beings make decisions in about one-sixth of a second is factored in.

Findings also showed that there is alternating peak sensitivity.At one moment one ear seems to be at the peak of sensitivity to sound then the next moment it is the other ear.This always goes on back and forth.But it happens so fast that one can hardly realize.This was shown to be true in experiments where fine sound is manipulated and timed accurately.

Why then would our senses play tricks on us?Well, it is the brain's doing.With five different means to take in information, the brain opts to sift through data from different senses quickly then recreate one complete package of information.The authors of the research explain that the brain quickly reflects the action of attention through the sensory organs.Here, it rapidly samples neural activity in each sense and gives the feedback back to the brain for analysis and reconstruction.This is how fluctuations in the attention of our senses come about.

How the Strobing Brain Works:

With the intent to examine an environment, the brain seeks information from its sensory organs.However, at that moment, not all organs will be equally important.For example, if you were in an opera house watching a performance, your sense of touch and taste may not be as important in gathering information about your environment as your ears and eyes would be.This way, your brain filters attention to the most relevant organs at the moment.But due to the consistent flow of events, to keep up, the brain allocates cognitive resources (attention) into small temporal epochs that can be sent from and back to the brain for interpretation and on again to gathering data on the sensory organs, thus, creating an oscillatory perception.

The researchers say that with this newly uncovered information, their new objective is to study, understand and characterize perception as a whole.Oscillations in sight-perception and auditory-perception have been uncovered now.But the functioning of attention in other senses is still mysterious.Their next focus is how perception of touch manipulates oscillations to interpret and recreate the surrounding.

Our understanding of perception goes beyond just understanding how we see the world.This research shows that perception of the world through our sensory organs is cardinally oscillatory.Therefore, it influences our understanding of human behavior, how humans interact with their immediate environment, and how humans are influenced in making decisions.

Professor Alais concluded that the brain is such a complex machine.Science has brought to light much of its wonders, but there is still so much not known about it.There is a lot to be learnt and understood about the human brain. "A decade ago, no one would have thought that perception is constantly flickering like an old silent movie," Prof Alais exclaimed.

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