Micro Eye Movements Keep Still Life From Fading Away

See this picture on the left? Try staring at the red circle for a moment, while paying attention to the gray ring. After a few seconds, doesn't it seem to that the circle fades away and you're left with just a red dot on a white background?

You can thank Ignal Paul Vital Troxler for figuring that out: according to this Swiss philosopher, we now that that deliberately focusing on a fixed object causes other surround stationary objects to fade away.

Once you move your eyes, the gray circle should be visible again.

So what is actually going on here?

According to scientists, our eyes are always in motion and there's one type of motion we control, called saccades, such as when we deliberately scan a room, and one type we don't, microsaccades, which are just as crucial.

To understand why these microsaccades are so important in our visual perception, its also important to understand the concept of neural adaptation. Much like our nervous system adapts to the constant, unchanging stimulus of us wearing a watch or glasses, for example, the visual neurons would too adapt to constantly unchanging (static) visual stimulus. The article uses the example of a frog that cannot see a fly sitting on a wall but can see it as soon as the fly starts flying around. Our visual neurons aren't comparable to Kermit's but we also use these tiny subconscious movements, these microsaccades, to keep our visual neurons from "falling asleep" and causing stationary objects to drift away.

Research on micro-saccades is pretty niche but it isn't new — the article cites studies from the 1950's, one in particular where scientists created and fit a tiny projector over the eye in order for the visual scene to move with these micro-movements. They basically stabilised the retina, rendering the microsaccade motion useless. (If anyone reading this is a photography buff, you can think of microsaccades as the inverse of the Image Stabilizer found in some of the pricier lenses. What it does is much like what your eye does: it creates internal micro-movements within the lens to prevent image blur when shooting pictures while holding your camera, helping to combat the natural shaking of an unsteady photographer. But, if you inadvertently leave it on while shooting with a tripod, the stabilizer actually causes the blur. Our eyes want to do the opposite, they want to keep the image shaking.)

More modern research uses computer eye-tracking devices linked to a projector that moves the image you're looking at with the movement of your eyes; no more wearing scary suction cups over your eyes to participate in this type of study.

The article goes on to discuss the potential neuronal responses the micro-saccades are responsible for generating in the brain. (research with monkeys showed activation in the lateral geniculate nucleus and the primary visual cortex)

What I found particularly interesting about these micro-saccades is that researchers found that they may be useful in determining what it is we are actually paying attention in our visual field, even inadvertently. Research done at McGill University found that the direction of microsaccades was often biased in the direction where subjects were actually paying attention. Another, different, study showed that the frequency of the microsaccades affected visibility: the larger they were, the better the visibility. Or, as the article put it:

"microsaccade frequency can betray your attentional spotlight."

This article seemed pretty spot on in discussing the purpose of microsaccades and sites of possible neuronal activation, but as a point of criticism, with the advent of "neuromarketing", I think its only a matter of time before labs that use EEG and eye movement tracking (usually of saccades, the bigger, intentional movements we make) will also claim to be able to track our microsaccades to tell their clients "what we're really thinking" without factouring into account that microsaccade activity correlates with other brain activity in an EEG reading (gamma band activity, to be specific).

http://www.scientificamerican.com/article.cfm?id=shifting-focus

Can Our Brain Predict Item Popularity?

What taste do you prefer more? Pepsi? Coke? Can you tell the difference between the two or are you choosing based on what your peers like? Or maybe the label? Or do you really honestly and genuinely enjoy one more than the other? How about a singer? Whose song is going to be a #1 hit this year? Scientists started to get curious about the pleasure response in our brains. If people’s brains activated more for one thing than the other could brain scans predict which thing was more popular? They did this experiment using songs. They tested a number of young adolescents in an MRI scanner and started playing a variety of music clips that people downloaded from social networks. While listening to the each song, the intensity of brain activation was measured as well as the subject’s personal rating of the song itself. They then started focusing on the parts of the brain whose activity was correlated with the subject’s likability of the song.

After waiting for years, they separated the songs they played during the scans into songs that became extremely popular, songs that became somewhat popular and songs that just never made it to the radio and then they tried to match it up with the amount of activation they caused a part of the brain. Did brain activation correlate with how popular a song became? The closest area that came close to predicting top hits was the nucleus accumbens although it is not the highest of correlations. I did a little more research on the nucleus accumbens since the experiment in the article stated that the study was not designed to specify how this brain structure did that.

It has been proven with PET scans that our brains activate to music. Anyone who has done a little more extensive research on music effects on brain might also have read that our brain is selective in the type of music we choose to like or dislike (which was what started the idea for the experiment above). Our brain produces the ability to put reward value on music that we enjoy because songs can evoke positive (or negative) feelings. These feelings of emotional responses increases and decreases the blood flow of the cerebrum which harbors our arousal, emotion and motivation systems. Coincidentally the same location where other heavenly feelings and senses are induced, such as food, sex and drugs. Not surprisingly the nucleus accumbens resides in the brain as a key part of the mesolimbic pathway, a system that deals with a particular neurotransmitter..can you guess? ......Dopamine! No surprise there.

If the above experiment did not induce any enthusiasm in you, then I couldn’t agree with you more. The experiment itself, I believe, only proved that we could just predict hit songs just by simply asking someone if they liked the song or not and tallied up what the majority’s favorite. Besides the experiement did mention that they also asked the subjects their own person rating on the song. But the findings of this experiment did spark an idea . The article did mention that the study was indeed a valuable and compelling study in neuromarketing. Maybe the focus should have not been towards songs. Besides there was an array of things that could of skewed the experiment like having a small nonrepresentative sample, picking songs from one source, subject bias..etc.

This same experiment could be reconstructed in a way where a subject’s choice interference such as “wanting to like or dislike a product”, subject bias, picking according to label of product and not actual product itself etc, could be discluded from the experiment. This could be done by placing two different products, into two identical unlabeled containers, having a subject try both and rate which one they like better while doing a scan on the brain. Then at the end of the experiment, they can be given a questionaire in which they can consciously choose which brand name they would prefer. Compare their results. If the results are positively correlated, then competing companies can know that passing out surveys might be just as reliable as the brain scan.

Actually, the reason why this experiment was significant was because large companies want to know if people really do enjoy their product much more than the competing company’s products and many are willing to pay the big bucks to prove this scientifically to the world. Sure, this might not be such great news to most scientists striving to find the cure to Alzheimer’s or anyother neurodegenerative disease, but it is awesome news to the marketing industries and future advertising strategies. In fact big companies, such as Coca Cola and Pepsi are leaning toward techniques such as neuromarketing and neuroeconomics to learn more about the consumer’s brain and how our brain, rather than our spoken opinions, respond to their products. They spend millions of dollars on techniques to make sure that our brain responds to their advantage as indicated in this youtube vid. http://www.youtube.com/watch?v=Swy0jAaECxk Don’t get me wrong, big brand name companies have been using the brain to up their sales for years! Just google : subliminal messaging in advertisments. I just thought it might be interesting to see where all this could lead to in some distant future..imagine a high tech robot with a mini brain scanner in the palm of her hand “You voice that your preference would be a maroon BMW but activity level in your the nucleus accumbens suggest an 80% probability that your actual preference is this silver Mercedes.”

Article can be read here: http://www.scientificamerican.com/article.cfm?id=brain-scans-predict-pop-hits&page=2

Further research http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1693452/pdf/15590614.pdf