Every human has limits. You can only run so fast, jump so high, and go for so long without water. But what about restrictions upon our five senses, those tools that we use to perceive and understand our surroundings? Here are ten limitations on human perception that have a direct impact on how we understand the world.
Vision
About one quarter of the human brain is involved in visual processing – more than any other sense. Arguably the most closely studied of the five main senses, the Society for Neuroscience claims that more is known about vision than any other vertebrate sensory system. A pair of healthy human eyes has a total field of view of approximately 200 degrees horizontally — about 120 degrees of which are shared by both eyes, giving rise to what’s known as binocular vision — and 135 degrees vertically, (though these values tend to decrease with age). This is due to the fact that both of our eyes are positioned more or less on the front of our heads, as opposed to the sides. Having eyes positioned on the sides of one’s head is common in prey species, and while it certainly increases an animal’s total field of view, it’s often at the expense of sharper binocular vision (see the helpful chart featured here, which shows the differences in vision between pigeons, whose eyes reside on the sides of their heads, and owls, who, like humans, sport front-facing peepers).
Hearing
Commonly listed alongside vision as one of the most important of the human senses, hearing is is a vital part of everything from communication to risk-avoidance. Among young, healthy humans, the range of frequencies that can be picked up by the human ear is usually cited as 20 — 20,000 Hz; however, the upper limit on that range tends to decrease pretty steadily with age. Your absolute threshold of hearing is the quietest sound your ears are capable of picking up when there are no other sounds around to mask its perception.
Taste & Smell
These two senses rely on different sensory organs, but are very closely related; when someone loses his or her sense of smell, for example, their sense of taste is dramatically diminished. The sense of taste is arguably the weakest of the human senses. This is something we’ve talked about before; your ability to “taste” wine, for example, is actually more dependent upon your sense of smell. Here’s what we had to say about the limitations of taste back in March: In what is hands down my favorite experiment on the limitations of the human palate ever performed, researcher Frédéric Brochet invited 57 wine experts to give their opinions on what appeared to be two glasses of wine – one red, and one white. The wines were actually the exact same white wine; the “red” had simply been mixed with red food coloring.
