Experimenters in the Zoological Institute at Rostock before World War I coined the term “umwelt” to describe a creature’s perceptual world. In particular, they investigated the cattle tick which is a small, blood-sucking arachnid (eight legs like a spider).
The eye-less female tick hatches from an egg, feeds on various cold-blooded animals, sheds its skin several times, mates, and then climbs to the tip of a twig or bush. There she will perch, through light and dark, fair weather and foul, waiting for one thing only – the scent of mammalian sweat – for up to eighteen years! During this time, her metabolism is slowed drastically. Her fertilized eggs are also suspended. The passage of time means nothing to it – it doesn’t perceive it.
The smell of sweat is the only experience that will trigger time into existence for the tick. Then it suddenly comes alive, launching itself toward the scent. If it lands on a warm body, the tick proceeds to fill itself with blood, drop to the ground, lay its eggs, and die.
As you can see, the cattle tick’s world is very limited compared to ours. For most of its life it knows of, and senses, only one thing: sweat. A human’s umwelt would then be “the world” as he/she perceives it. But, as will become clear, this perceived world is far from all we actually know about, let alone all there may actually be.
Humans can only see a small portion of the electromagnetic radiation (light) spectrum. But the entire spectrum includes radio waves, infrared radiation, ultraviolet light, X rays, and gamma rays. These things we cannot perceive directly – their particular frequencies and wavelengths are invisible to us. But from experiment, we know that bees can see ultraviolet light. What would our world look like if we could see, for example, radio waves?
We can only hear a certain range of sounds too. But dogs are well known for being able to hear pitches that are undetectable by human ears. What would our world sound like if we could hear everything? (I suspect noise pollution would take on a new meaning!)
Our sense of smell is likewise limited. Once again, dogs can pick up odors far too faint for our noses to detect. In fact, scientific research strongly suggests that dogs conceptualize their world mostly in terms of smell. If we could smell as well as a bloodhound, would we like what we smelled?
Taste could be interesting if our taste buds could detect all that’s possible. Research has shown that some children (at varying ages) don’t like certain foods simply because they can detect unpleasant things in the same food adults like! But what would it really be like to be able to taste everything?
Our sense of touch seems to be highly developed, but we still cannot feel the cold of deep space or the intense heat of the sun beyond that point at which our fingers freeze solid or burn up. Perhaps that’s just as well!
So, while our umwelt is obviously limited to only a portion of reality, at least we can imagine more than we can actually experience. And we can experience more reality at least vicariously through technology and scientific experiments. But,… what would the world really be like, if…