June 6, 2026
People say believe half of what you see...
An essay identifying that something we believe to be real, our eyesight, leaves room to question what we think we see.
5 min read
I am fascinated by the human brain and how it creates a sense of reality, or consciousness, for us to exist in. Our vision is even a virtual representation that our brain creates.
Our Virtual Reality
When light hits the cells in your retina, they convert this light into electrical signals. In effect, they translate light into a language your brain understands. Those electrical signals travel along the optic nerve to the back of your brain, where the visual cortex processes everything. Here is where it gets weird…
Your brain doesn’t receive an image, it actively interprets the electrical signals to construct the image of what you’re seeing. It fills in gaps, it recognizes objects, it understands depth, and it compares what you see to memories of previous events. What we see isn’t ‘real’, it is an interpretation of what our brains thinks we see.
This leads to some very interesting outcomes and explains why optical illusions work, why de ja vu occurs and why sometimes you think you see something that a second later you realize that it isn’t there. Your brain makes assumptions and sometimes gets it wrong.
How Beliefs and Bias Affect What We See
Jack Rothgerber, PhD, in Psychology Today identifies that the structure of people’s eyes and how their brain interprets signals differ which makes different people see different colors or visual details of the exact same image.
People assume that what they see is a direct reflection of reality and this is known as the objectivity illusion. It’s considered an illusion because people’s beliefs and biases directly shape what they see. Human evolution has seen to it that people subconsciously confirm that even relatively straightforward visual representations validate their previous worldview.
Vision Is Like A Movie
Not only do we subconsciously change what we see, sometimes there are medical or physical reasons for us not trust 100% in what we view. In the book Awakenings, Dr. Oliver Sacks describes patients he met at Beth Abraham Hospital chronic-care facility in the Bronx, New York, where he worked after his residency. These patients were survivors of the encephalitis lethargica (or sleeping sickness) epidemic of the 1920s. By the time they became patients at Beth Abraham, most were experiencing extreme Parkinsonian symptoms.
They would appear lost in some void or frozen in place. Most had ambulatory issues or communication issues. Some of these patients experienced symptoms that could genuinely make you uneasy about how our brains operate.
He details patients who experienced what he described as “kinematic vision”, or they could basically see their vision as frames since, to them, their vision had slowed down so that it wasn’t fluid. These patients, at times, described a phenomenon where one or more of the frames would occur out of chronological order. The frame(s), or moment, would occur too soon or too late.
One patient described a visit by her brother during which her vision was proceeding at about 3 to 4 frames per second. For reference, most movies are shot at 24 frames per second and this motion seems ‘normal’ to us. This patient recalled seeing her brother light his pipe prior to the match being struck. She essentially saw the future, somewhat before she was supposed to see it.
In the footnotes, Dr. Sacks goes on to describe that normally our vision proceeds correctly. There are now documented medical cases where, in certain conditions, the moments we experience may be fed to us in the wrong order. Even though we perceive our vision as a series of “nows”, or moments, this phenomenon causes fragments of our moments to get out of order and we see things either before or after they actually occur.
This is a great example of the fact that our brain recreates what it perceives we are seeing and since it is not the actual imagery there is the possibility of our vision to be rendered incorrectly. Maybe we shouldn’t look upon our vision as the God’s honest truth of what we are witness to.
Real Life Impacts
There are real impacts to the fact that even what we see for ourselves isn’t beyond critical inspection and the possibility that we got it wrong when we witnessed something.
I used to believe that capital punishment was an acceptable punishment so long as a witness testified that they saw first hand the defendant committing the act in question. Now that we better understand how our brain interprets what we see, in addition to how memories are stored and that they are susceptible to their own errors, I can no longer support capital punishment.
On a lighter side, I second guess and try really hard to look objectively at close calls in sporting events, too. Whether it’s a tackle in soccer or a sideline pass in football, our emotional attachment to a team can color our judgement; it can literally change what we see.
I find it funny that I’ll be in a room of fans yelling at the TV that the player was in bounds when the objective eye can clearly see the player’s foot touching the sideline. We just don’t want to believe it so much that our mind makes it so.
Maybe Norman Whitfield and Barrett Strong knew this about human eyesight when they wrote the lyrics in Heard It Through The Grapevine. As Marvin Gaye sings it:
“People say believe half of what you see,
Son, and none of what you hear”
They get it right that our eyes aren’t perfect. Believing half of what we see can help us account for our biases, our memories and just our being human.
Previous Reading:
Rothgerber, Jack, PhD (2023, May 23). How Can We All See the Same Thing and Still Disagree? Psychology Today. https://www.psychologytoday.com/us/blog/the-motivated-mind/202305/how-can-we-all-see-the-same-thing-and-still-disagree
Sacks, Oliver. (1990) Awakenings. HarperCollins Publishers, Inc.