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Although it may not subjectively seem to be the case, the human visual system only allows us to fully perceive a very small portion of what we seem to see.
The fovea centralis is a tiny pit in the center of our eyeballs in which cone cells—photorecepting cells that detect variations in the wavelength of light, and which thus allow us to perceive color—are especially densely packed.
This region is what allows us to have particularly sharp vision at the center of what we might call our line of sight, but only at the very center.
The upside of which is that although we think we see a great deal of our environment quite clearly—if you look around wherever you happen to be, right now, and if you have average or better visual acuity, you’ll probably feel as if you can see everything within a certain radius in front of you—in fact we only actually perceive a concise region at the center of our visual range with clarity, while the rest is somewhat rough and fuzzy.
Our brains fill in the details of that outer visual region, not our optical systems. Which means there are likely to be flaws in our assumptions, and this is perhaps more true in unfamiliar circumstances than familiar ones.
One practical consequence of this biological setup is that we are more capable of truly focusing our attention on select things, while relegating less cognitive power to distractions beyond that central point of focus.
Objects not in our direct line of sight are literally less clear, less in-focus, than those at which we’re looking, straight on.
The capacity to manage our attention—to consciously shift this focal point from one thing to another—is a bit of a human superpower. Other animals can do it to varying degrees, as well, but our control over the target of our focus is more potent and refined than in any other species we’ve researched, which may indicate that it has some connection to our capacity to consciously cognate; to think about specific things, rather than our thoughts being entirely controlled by something more like instinct.
This visual setup also has interesting implications for non-verbal communication with each other and with other animals.
The direction our retinas seem to be pointing tells those who can see our eyes where our attention is focused: what we can see clearly in our environment at that moment. The awareness of what others are focusing on in a given moment is important data that we pick up on, often subconsciously, and then utilize as part of a larger body of nonverbal cues as we socialize.
Some other animals can pick up on this data, as well, and dogs in particular seem to have developed a refined sense of what humans in their vicinity are looking at, which may be a coevolved trait they developed as a means of benefitting from social information that is otherwise only intelligible to other humans.
There’s also research that suggests data in our environment influences our thinking and unconscious responses more potently when it’s perceived through our foveal receptors, compared to simply being within our overall visual range.
A potential threat, then, be it a large, toothy animal, or an overdue credit card bill, may cause us to go into fight-or-flight mode if we’re looking straight at it, but if the same threat is perceived out of the corner of our eye, or even off-center from our foveal radius, we may be aware of the threat but not respond to it the same way.
There may be gradients to our sense of the world, in other words, based on how much detail we’re able to take in about it, and how focused we are on it. And that detail and focus is determined, in part, by how directly we happen to be looking at it.
All that said, much of the research in this space is still relatively new, and most of it is predicated on average visual arrangements, not universal rules.
This concept wouldn’t apply to people who are blind, for instance, and it would likely apply differently to people with distorted or unreliable vision.
But those variations may prove to be an interesting realm of inquiry, as well, as they might help us further understand how attention—and the quantity of attention we pay to various things in our environments, utilizing whichever sensory organs we rely upon in a given context—influences our conscious and unconscious perception of the world around us.
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