This unscientific survey and the reponses remind me of Plato's allegory of the cave. In the allegory, people are chained up in a cave, facing a wall on which are projected the shadows of objects passing between a fire and the wall. The people cannot see the objects themselves, only their shadows. Plato used this allegory to explain there is a reality truer than what we perceive, and this reality consists of theoretical forms. (For the CliffsNotes version, watch The Matrix.)
The allegory is useful in a semantic/linguistic context. When I say "dog," you may imagine a hundred different breeds of dog, all of which would be correct. Lassie and Cujo are both dogs. But in our shared language, there's a theoretical dog that all those dogs are particular instances of.
When I tried it, I was surprised how long it took me to see anything. When I'm writing, I envision spaceships joined by a latticework of human-sized hamster tubes, mining colonies on the slopes of a Martian volcano, an island city situated in the middle of a crescent-shaped bay. Something as simple as an apple should be child's play! But all I saw at first was the dark red of the backs of my eyelids. I didn't get a clear picture of the apple until I imagined picking one up and eating it. Touch and taste are unique properties of an apple, so that helped.
In Theaetetus, Socrates says "the mind in itself is its own instrument for contemplating the common terms that apply to everything." In other words, knowledge is the ability to intuit universals from a set of particulars. What does it say about people if they can barely recall the shadows of the real objects they cannot see? How does that bode for their capacity to perceive universal truths?
The armchair psychologist in me says being surrounded by hypervisual media causes the other senses as well as the imagination to dull. I live as if that's true, and limit my kids' screen time accordingly.
By the way, 400 years after Plato, Paul wrote to the church in Colossae:
Therefore do not let anyone judge you by what you eat or drink, or with regard to a religious festival, a New Moon celebration or a Sabbath day. These are a shadow of the things that were to come; the reality, however, is found in Christ....and the author of the letter to the Hebrews wrote:
The law is only a shadow of the good things that are coming—not the realities themselves. For this reason it can never, by the same sacrifices repeated endlessly year after year, make perfect those who draw near to worship.
As always, let me know what you think in the comments. If you like sci-fi, check out my books Seeds of Calamity and Tendrils to the Moon. You can find extended previews for each here and here.