• Robb G. Best

Umwelt: Beyond the Five Senses, or, the Mr. Potato Head Model


All of the information that comes to your brain arrives through your senses. Sight, smell, touch, taste and hearing are conduits to the perfectly dark and silent world inside your skull where the most powerful processing machine in the world resides.

And yet, for example, we know that we see only a billionth of what is front of us. Even honey bees and snakes see a spectrum of light far beyond what we can detect. The animal kingdom is rich with creatures that have adapted to see, hear, feel, smell and taste far beyond our meager human abilities. Bats can hear insects flying from 15 to 20 feet away, and polar bears can sniff out a seal through three feet of ice.

The entire world of our perception is what scientists call our umwelt, and ours is quite limited. I might have conceptual knowledge of the X-ray that pulses through my body every time I go through security at an airport, but I can’t register it in any meaningful way, and the same is true of radio waves, magnetic fields, and so on. Put simply, I just don’t have the hardware for it.

So it seems we are prisoners stuck in a tiny sliver of objective reality, constrained by the limitations of our biology.

Not so fast, says David Eagleman, PhD and neuroscientist. At the Being Human conference in San Francisco last week, Eagleman discussed a series of experiments that are rewriting our notion of experience, and what it means to, well, be human.

Eagleman explains that the brain’s incredible power lies in its plasticity. Think of your brain as a computer running code. If you can deliver code to the brain, it will figure out a way to run it. Part of the neuroscience Holy Grail is understanding just how the brain does this.

In the animal kingdom, animals have all kinds of interesting physical apertures to detect their umwelt. The blind tick understands the world through odor and the recognition of butyric acid. Vampire bats sense air compression and rattlesnakes have heat pits that send temperature readings to their brains.

Evolution has created a wide variety of biological receptors, but they all plug into a fairly standard processing system shared by many species. The plasticity of the human brain means we can co-opt our sensory delivery systems for unintended purposes.

In one experiment, a picture of a face was represented as a pictograph through needle pricks on a blind subject’s back. The nerve endings in the skin transferred the data to the brain, where it was decoded and the blind subject was able to report what he was “seeing.”

Eagleman half jokingly refers to this substitution of biological receptors as the MPH model of Evolution: the Mr. Potato Head model. He says we are more like Mr. Potato Head than we realize.

No matter what sensory system you use, like a dutiful computer programmer, it will find a way to run that code. The more we take advantage of this, the more we expand the potential of our umwelt.

To that end, Eagleman and his team are in prototype experiments to help blind people “see.” They have created a vest that picks up sound waves bouncing off objects, then sends these vibrations to the brain for processing. The brain can translate this back into spatial information, allowing someone with no vision to perceive the objects around them.

It is mind-boggling to imagine the possibilities. It makes the cochlear implant look like child’s play.

Hold on to your vest; your umwelt will never be the same.


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