CEO CORNER: THE EVOLUTION OF VISUAL PERCEPTION

By Jon Karafin

January 28, 2020

They say you can’t believe everything you read. Actually, we should say you can’t believe everything you see. Unfortunately, our visual perception of reality is heavily influenced by millions of years of evolution — and we don’t even know it’s happening!

The sensory overload of the 21st century can be overwhelming. We generate more information today than ever before throughout human history. We spend more time on our displays and devices than we do anything else in a lifetime.[1] We have more processing power within the devices at our fingertips than Apollo mission control.[2] Information scientists estimate we have now created more than 300 exabytes (300,000,000,000,000,000,000 bytes) of man-made information.[3]

Humans have created greater than 300,000,000,000,000,000,000 bytes of information


However, our brains aren’t able to process it all — because they aren’t designed that way.

Our brains and associated sensory receptors evolved throughout the hunter-gatherer phase of human history to help us survive. The ability to rapidly, sequentially, and automatically focus attention was, prehistorically, often the difference between life and death. According to scientists, various automatic subconscious processes choose what sensory information is passed through to our consciousness. For this to happen, “millions of neurons are constantly monitoring the environment to select the most important things for us to focus on.” [4]

Collectively, these neurons comprise something neuroscientist Daniel J. Levitin calls the “attentional filter.” He continues:

“When our protohuman ancestors left the cover of the trees to seek new sources of food, they simultaneously opened up a vast range of new possibilities for nourishment and exposed themselves to a wide range of new predators. Being alert and vigilant to threatening sounds and visual cues is what allowed them to survive; this meant allowing an increasing amount of information through the attentional filter. … Humans are, by most biological measures, the most successful species our planet has seen. We have managed to survive in nearly every climate our planet has offered (so far), and the rate of our population expansion exceeds that of any other known organism. Ten thousand years ago, humans plus their pets and livestock accounted for about 0.1% of the terrestrial vertebrate biomass inhabiting the earth; we now account for 98%. Our success owes in large part to our cognitive capacity, the ability of our brains to flexibly handle information. But our brains evolved in a much simpler world with far less information coming at us. Today, our attentional filters easily become overwhelmed.”[5]

For example, Levitin says our inability to remember specific details of highway scenery after a long drive indicates one way these filters protect us from the “perceptual detritus of our daily lives.” The attentional system unconsciously filters sensory information to protect you from unimportant visual data but allows certain other information to pass through to your conscious awareness.[6]

To further quantify the attentional filter, researchers Mihaly Csikszentmihalyi and Robert Lucky both independently estimated the processing capacity of the conscious mind at 120 bits per second[7] while other researchers have more conservatively suggested a maximum capacity of 50 bits per second (bits/s).[8] Although the exact bandwidth is up for debate, scientists agree that the maximum transmission capability of the mind is more limited than once thought. Fifty to 120 bits is a hard concept to parse, given the computational power available throughout all of our devices today. Basically, it suggests that our conscious minds handle 500-1,000 times less information than an old-school 56 kbit modem (at 56,000 bits/s)[9], and 1,000–2,000 times less information than your average MP3 file (at 128kbits/s).[10]

As an audiophile, I’m horrified.

Your conscious mind handles 500-1,000 times LESS information than a 56kbit modem


How is this possible? It’s all about survival.

The human brain evolved over millions of years to filter and focus over an estimated 11 million bits per second that the sensory receptors for all five traditionally accepted human senses are sending to the brain for processing. [11] Of the five senses, our brains have evolved to prioritize a magnitude greater amount of information from the visual system than all of the other senses combined. The below table demonstrates the rough orders of magnitude of the human sensory receptors and the maximum bandwidth of the conscious mind:

Sensory SystemBits Per Second[12]Visual / Sight~10,000,000 bits/sSomatosensory / Touch~1,000,000 bits/sAcoustic / Sound~100,000 bits/sOlfactory / Smell~100,000 bits/sGustatory / Taste~1,000 bits/sConscious Mind~100 bits/s

Figure 1 – Estimated sensory receptor transmission and conscious mind transmission limit in humans


Our brains have evolved to prioritize a magnitude greater amount of information from the visual system than all of the other senses combined


In order to understand someone speaking to us, we need to process approximately 60 bits/s.[13] Reading at a typical rate of 300 words per minute requires us to process approximately 50 bits/s.[14] If you’ve ever tried listening to someone talk to you on the phone while simultaneously attempting to listen to someone speaking to you in person, you have likely experienced this bandwidth limitation. You were forced to either prioritize one person over the other or split your focus and only process pieces of both conversations.

Figure 2 - Motor and Sensory Regions of the Cerebral Cortex [16]
Figure 2 - Motor and Sensory Regions of the Cerebral Cortex [16]

The sensory cortex is the region of the cerebral cortex responsible for receiving and interpreting sensory information provided by different receptors throughout the body.[15] Millions of years of human evolution have formed numerous neural pathways, increasing the probability of survival generation after generation. The resulting quantity of neurons in the brain dedicated to each individual sensory cortex supports the amount of sensory bandwidth the brain is capable of receiving at any moment in time. Human evolution has prioritized a magnitude more available bandwidth for the visual sensory systems, making vision the most complex and important of our senses when it comes to understanding the world around us[16].

Visual perception is the most powerful and complex of human sensory systems. For example, each of the two optic nerves that carry signals from the retina to the brain consists of a million fibers, compared to just 30,000 in each auditory nerve. Researchers say the retina, with 150 million light-sensitive rods and cones, is actually an outgrowth of the brain. Hundreds of millions of neurons dedicated to visual processing take up about 30 percent of the cortex, compared to 8 percent for touch and just 3 percent for hearing.[17]

30% of the cortex is devoted to visual processing, with only 8% for touch and just 3% for hearing


In the past two decades, researchers have concluded that the visual system is even more complex than previously believed in that the same sensory input is divided across many different pathways in the brain simultaneously to process (at least) color, motion and form independently. Researchers highlight certain conditions or injuries that leave people with highly specific visual deficits, including loss of color vision, motion perception challenges, or the ability to recognize faces to demonstrate the separation of these visual pathways.[18]

Although neurobiologists do not yet agree how many separate systems are involved in analyzing visual information, it is known that there are at least two systems. Motion, direction, borders, lines, contours, depth and brightness are processed in a completely separate visual system from color, form and detail. [19] Some researchers believe there are three or four visual systems (or possibly more).

These visual systems need to work together to provide us with an accurate visual representation of the world. However, because certain visual parameters are processed separately, visual conflicts may occur. Further, if not all of the visual pathways are leveraged, our visual perception of a particular object will not be experienced the same way as when all of the visual pathways are leveraged.

Motion and color are processed in completely separate pathways of the visual system


When the visual systems are presented with visuals lacking certain types of information (for example, a 2D image that lacks complex depth cues when compared to a real object), the brain uses strategies to fill in the remaining information unbeknownst to the individual. One of the best-known occurrences is the natural blind spot within each eye that we are, generally speaking, unaware of. The blind spot is the point where the optic nerve is connected in an eye, forming a patch on the retina that doesn’t respond to light. The blind spot is off-center toward the sides of your visual field by a distance about the size of a golf ball at arm’s length. When both eyes are open, the brain leverages the other eye’s information to fill in the blind spot. When only a single eye is open, the constant motion of the eye prevents the spot from lingering (and becoming visible) at any one location. Further, even if there is no available visual information, your brain will not leave a blank spot in your visual field in the event. Rather, it will create new information based on whatever background it thinks should be there. This is a subject of debate, but many conclude this process is carried out by a region in the brain that is at a higher level than the visual cortex, employing a process called “logical interference.”[20] When you say your eyes are “playing tricks on you,” you’re really referring to the brain’s interference with your perception of the visual stimuli it has received.

Neurobiologist Semir Zeki explains that the brain actively constructs or invents the visual world around us. “Confronted with an overwhelming barrage of visual information, it must sort out relevant features and make snap judgments about what they mean,” he says. “It has to guess at the true nature of reality by interpreting a series of clues written in visual shorthand; these clues help distinguish near from far, objects from background, motion in the outside world from motion created by the turn of the head.”[21]

All of this research implies that human visual perception is influenced by the brain’s need to filter out a massive amount of incoming sensory input and process the remaining data extremely quickly, as an evolutionary survival instinct. Multiple pathways process the information and the brain independently forms new information as required to support rapid decision-making. Some researchers describe the “top-down” influence of the cortex on perception to include previous experiences and emotional responses that form future expectations and affect our perception of visual information.[22]


Figure 4 - This image went viral because people are divided in what they perceive-either you see a blue and black dress, or you see a white and gold dress [24]. Which do you see?
Figure 4 - This image went viral because people are divided in what they perceive-either you see a blue and black dress, or you see a white and gold dress [24]. Which do you see?


Figure 4 demonstrates these perceptual phenomena. The colors of this dress are interpreted based upon the brain’s prior experience, given the ambiguous nature of an isolated 2D image where the materials and ambient light source are unknown. Individual sensitivity to colors and other experiences may influence your perception of the colors of this dress. Do you see blue and black, or white and gold? It’s a topic of heated debate. Show it to someone else and see if they agree with you![23]

The number of neurons from the higher-level cortex that analyze, synthesize and alter raw sensory data far outnumbers the incoming sensory neurons. Scientists conclude that the influence of the brain and our expectations are more influential to perception than the raw sensory data. In documented instances, individuals may believe they see something based upon a higher-level cognitive expectation that isn’t really there. Similarly, they may believe they did not see something that actually exists, thanks to their contradictory expectations. [24]

50% of people see a blue and black dress. 50% of people see a white and gold dress


In a famous experiment that demonstrates both the attentional filter and the influence of expectation, people are shown video footage of a group of people playing basketball and are instructed to concentrate on their activity by counting the number of times the ball is thrown or concentrating on another, similar aspect of their behavior. Partway through the sequence, a man in a gorilla suit walks across the frame. Remarkably, a majority of viewers do not see the gorilla because their otherwise occupied visual system limits the bandwidth of processing to this clearly focused task they’ve been specifically asked to perform. Additionally, none of them expects to see a gorilla.[25]

Figure 5 – Series of images from the famous experiment in which viewers asked to concentrate on a given task do not see the man in the gorilla suit walking across the frame. This exemplifies the idea of attentional filters as well as the influence of cognitive expectation. [26]
Figure 5 – Series of images from the famous experiment in which viewers asked to concentrate on a given task do not see the man in the gorilla suit walking across the frame. This exemplifies the idea of attentional filters as well as the influence of cognitive expectation. [26]
Most people in the study don’t see the man in the gorilla suit!


Other studies of the effects on perception demonstrate: [27]

  • A photograph of a bright light causes the pupil to react as if looking at a real light source
  • Thinking about good deeds makes the environment appear brighter than reality
  • Thinking about bad deeds makes the environment appear darker than reality
  • Words related to food appear brighter than reality when the participant is hungry
  • Skilled baseball players view the ball as larger than reality
  • Underprivileged children view coins as larger than reality
  • Larger individuals estimate doorways as narrower than reality
  • Feeling an emotion can alter the visual perception of a scene


Let’s recap: what you actually see and what you believe you see, are significantly different things. Our brains have evolved over millions of years to form multiple visual neural pathways. We have come to understand and navigate the world around us by interpreting these visual impulses, and the human visuomotor system has largely evolved to perceive and interact with real objects and environments, not images or 2D illusions leveraged to simulate depth. (Refer to the previous article in this series, “The Holographic Dream,” for more on this subject.)

Only within recent history have we been uniquely overwhelmed by forms of data that are flat and two-dimensional. In the other millions of years of our brains’ evolution, they have perceived and stored memories about the world that possess additional cues providing depth, motion parallax, binocular disparity, shape, surface texture, specular highlights, perspective, and many others that fire up separate neural pathways in the visual cortex. Conversely, when we view a monoscopic representation of an object, we experience the stimulus as flat, which has been shown to disrupt object recognition, only exciting a subset of neurons in an already bandwidth-limited attentional system.[28]

There is truly no substitute for the real world—unless you have the ability to recreate it. This is where holograms come in.

The holographic future changes everything.

Read on to learn how holograms make the world a better place for your brain.


[FOOTNOTES]

[1] https://www.nielsen.com/us/en/insights/news/2018/time-flies-us-adults-now-spend-nearly-half-a-day-interacting-with-media.html

[2] - [5] https://www.fastcompany.com/3051417/why-its-so-hard-to-pay-attention-explained-by-science

[6] https://www.penguinrandomhouse.com/books/313653/the-organized-mind-by-daniel-j-levitin/

[7] https://www.fastcompany.com/3051417/why-its-so-hard-to-pay-attention-explained-by-science

[8] https://www.britannica.com/science/information-theory/Physiology

[9] https://en.wikipedia.org/wiki/Data-rate_units

[10] https://en.wikipedia.org/wiki/Bit_rate

[11] - [12] https://www.britannica.com/science/information-theory/Physiology

[13] https://www.fastcompany.com/3051417/why-its-so-hard-to-pay-attention-explained-by-science

[14] https://www.britannica.com/science/information-theory/Physiology

[15] https://human-memory.net/sensory-cortex/

[16] https://www.frontiersin.org/articles/10.3389/fpsyg.2019.02246/full

[17] - [21] https://www.discovermagazine.com/mind/the-vision-thing-mainly-in-the-brain

[22] https://www.academia.edu/9970676/Cognitive_Psychology_-_Visual_Perception

[23] http://jonlieffmd.com/blog/what-color-is-the-dress

[24] https://www.academia.edu/9970676/Cognitive_Psychology_-_Visual_Perception

[25] http://jonlieffmd.com/blog/how-does-expectation-affect-perception

[26] https://www.smithsonianmag.com/science-nature/but-did-you-see-the-gorilla-the-problem-with-inattentional-blindness-17339778/

[27] http://jonlieffmd.com/blog/how-does-expectation-affect-perception

[28] https://doi.org/10.3389/fnhum.2014.00837