Like many men his age, my husband has red-green color blindness. I was reminded of this recently when we were configuring our router and my role was to report the colors of the indicator lights. Like many people our age, he also has some missing frequencies in his hearing range; he can’t hear the chittering of our hummingbirds at all, while it seems nearly constant to me.

I feel strange when I look at lights he can’t see or hear birds he can’t hear. Then I started to think, if he’s missing some perceptions, I could be, too.

I took a hearing test at http://www.freemosquitoringtone.org; I could hear the examples from 200 Hz through 12kHz, but not below or above those. (The quiet hissing sound means you can’t hear it.) I was startled when I got to the level that showed the moving bar with “no” sound, that is, sound I couldn’t hear, and I spent some time adjusting my computer, to no avail. Evidence: there are sounds I cannot hear!

But what are they? Certainly some teen ringtones, and since those are patterned after bugs, then probably also some bugs. I’ve never been able to hear dog whistles, even as a child, which made me think about animals, and so I looked up animal hearing range by species–wow. Some animals hear quite different ranges. I’ve often wondered if human noises bother animals, and now I know many animals can hear sounds we can’t. Can we make noises we can’t hear? I’m guessing we can, or our machines can, and probably do.

For many of us, especially those of us trying to minimize our impact on nature, how odd to think we could be doing something we don’t even know about.

Another thing I uncovered: Even plants can hear to some extent, though that’s not something that has been well-researched to date. We observe effects on animals often, but I imagine we have no idea how we are affecting plants.

Of course, the visible spectrum also varies by species, with creatures that can see in the ultraviolet (insects and spiders) or the infrared (snakes). Birds can see many more colors than we do in what humans call the visible spectrum, I’m guessing because of their eye or brain configurations.

Neuronal processing isn’t the only way the brain affects perception. Think about how much more interesting a painting or a symphony is when you have studied it. Even listening to a pre-concert talk or getting guided tour headphones in the art gallery can make those listening and seeing experiences more meaningful and memorable. Whatever our physical constraints on perception, we can all use mindfulness to enrich our experiences. My husband may not hear the hummingbird, but he can look up and see it.