Your GPS is wrong

With the publication of my book, I'm getting more and more questions about the effect of using GPS'es on the human mind, and whether it degrades our abilities of spatial orientation.   There are plenty of studies that indicate that this is the case, but it's worth examining some of the details of what happens.

First, our brains have specialized parts that are adapted to hold maps of our environment and help us navigate.   These regions are part of the neurological makeup of all mammals.    Many parts of our brain are specialized.   Another part is a language center.   We're predisposed to learn languages when we're young.   The precise language is not a given, and depends on the culture surrounding us - the languages we grow up with and communicate with.   Like the language centers, the parts of the brain that carry maps of our surroundings have to be exposed to an environment that we travel through in order to acquire the internal map.  That is to say: we need to be actively engaged in the process of navigating to engage the relevant parts of our brain.

Very young children do not possess a cognitive map, but from about the ages of 6-12 begin to develop it.   We also have the ability to hold multiple maps in our mind, and can swap them in and out depending on our surroundings and mode of transportation.

So, what about GPS'es?    GPS devices come in many different flavors, but we're usually exposed to two varieties:  one is a car-GPS unit that gives us instructions on where to turn to get to a destination.  The second is a hand-held unit that often gives us some local portion of a stored map and tells us where to go to reach our destination.

The problem with a GPS is that it will give a very narrow window in space and time of our environment.   It will say "turn left in 200 yards",   "merge onto highway".   In doing this, there is no broader view that is necessary to acquire a knowledge of an area.     If we do nothing but use a GPS and rely on this one-off instructions, the parts of our brain that are wired to create cognitive maps go unused.    I fear that the over-reliance on these devices is creating a culture where we're helpless without them.

I deliberately go without GPS'es because I feel that I need to constantly exercise the part of my brain that is active in navigation.    Three months ago, I was at a meeting at Brookhaven National Laboratory on Long Island.  At the end of the first day, our host arranged for a dinner at a restaurant some distance away.   I asked him for directions.   He told me to just type the address into my smart-phone's GPS and follow the instructions. I said that I didn't want to use my smart -phone, could he give me directions.

It took him a long time to call up the directions from memory.   On one segment of the trip, he told me to drive about three miles down a certain road to get to the restaurant.    I got in my car and followed his directions.   It turned out that the 'three miles' he recalled was really fifteen miles, which confused me mightily.   The problem is that his sense of distance got distorted.   He later gave me directions back to my hotel, which again turned out to be wrong, but at this point, I had developed some sense of the area I was traveling through and was able to find my way without difficulties.

Now, you may be thinking:  "well, as long as I have my GPS with me, I'm fine, right?"   Well, wrong. What are the problems with GPS units?

In addition to the obvious issues of losing the ability to navigate without a GPS, they can fail in rather dastardly ways.   I spoke with a woman who was traveling to the College of Appalachia in Boone, North Carolina.   Her GPS was dutifully rattling off directions, but at some point, she was directed up a narrow winding road.   She said it didn't feel right, but she continued along, until she got to a hilltop with a very constricted spot where she almost couldn't turn around.   At the hilltop was a small house, and a sign that read, "Your GPS is wrong, this is not the College of Appalachia, turn around here."

She realized that her intuition was serving her well, but she trusted the GPS unit over her inner sense of direction.

In fact, many people have had experiences like this.   They're so common that people who live on quiet one way streets will often have to post "Your GPS is wrong" signs, because they're are tired of people who get steered in the wrong direction by their units and turn up at their doorstep.

GPS units are subject to many possible failure mechanisms.   Let me list the ways:

 Insufficient satellite coverage

GPS units receive signals from multiple satellites to acquire a position.   There are many satellites aloft that provide these signals, but sometimes the satellites fail, sometimes the orbital positions of the satellites are poorly aligned with respect to the user, and the unit won't acquire a position. 

Dead batteries

In portable units, batteries can die.   If you don't have spares, you're out of luck. 

Broken receiver

The part of the GPS unit that receives the satellite signal is a delicate piece of electronics.   Although most portable units are supposedly waterproof, the electronics can be exposed, over time, to environmental stresses that will cause them to break down.   I had a portable GPS device that I took with me while sea-kayaking, but over time it stopped working.   I attribute this to the receiver getting too much exposure to salt water and finally giving up the ghost. 

Atmospheric conditions

Every so often, solar storms kick up a spray of charged particles that flood our upper atmosphere.   When these storms hit, the charged particles in the atmosphere can kill the satellite signals, rendering the GPS units useless.   Other conditions, like thick fog and thunderstorms can degrade the satellite signals before they reach the ground. 


Terrain problems

Tunnels, tall buildings, and deep valleys can block satellite reception, making GPS  navigation in these places impossible. 

Software glitch

No software is error free.  Even if the geography database the GPS unit uses is correct, the unit's software may get confused when it encounters a condition that the developers never anticipated.  

Map error

Although the GPS unit might be able to tell you where you are within a few yards, someone has to make sure that the actual landmarks around you are correct in the database.   This is not always the case.    Humans have to enter information into databases that the GPS units use.  With the millions of locations that have to be stored, the odds that some or many of the locations are wrong is 100%.   This is probably what happened with the "Your GPS is Wrong" signs - the database had the incorrect information.

User error

Say you want to go to "Stephen's Parish", but you type in "Steven's Parish"?   Perhaps this are both a "Stephen's Parish" *and* a "Steven's Parish", but they're in very different locations.   Well, that simple typo will send you on a wild-goose chase. 


Jamming 

Yes, believe it or not, people can and will jam GPS units.   The signal-to-noise ratio of GPS signals from satellites is very weak, and it doesn't take a lot of radio power to confuse a GPS unit.   What's even worse, it was recently demonstrated that people and spoof, or fool GPS units by sending out fake signals.

Radio interference

GPS units operate at certain radio frequencies.   Although these are supposed to be "clear" in the sense that people don't broadcast at these frequencies, sometimes sources of radio noise can be so strong that they end up creating interference at these frequencies.   This can happen around power stations or other places that put out a lot of electromagnetic energy.