“Distinguishing the signal from the noise requires both scientific knowledge and self-knowledge.”
— Nate Silver
On June 2, 1875, Alexander Graham Bell and his assistant Thomas Watson were trying to increase the capacity of the telegraph by transmitting multiple signals over the same wire, using different frequencies. They stumbled on a way to transmit a voice as a signal over a wire — and the world was never the same.
Bell’s invention prepared the way for today’s hyper-connected world, but it also introduced more noise into the world.
Early telephone conversations were often scratchy, frustrating affairs. The new telephone network used the existing “naked copper” that was already in place for transmitting telegraph messages. The wires picked up the intended signal, the voice, but they also picked up any other noises in the background, anywhere along the way to the final destination. As signal volume increases, so does the noise. That’s why turning up the speakers beyond a certain optimal level may only make your favorite recording or TV program sound worse, and why hearing aids can be so frustrating in areas with lots of background noise.
Signal to Noise Ratio (SNR)
Power ratio is one of the simplest ways to calculate SNR. The higher the difference between the signal and the background noise, the stronger the signal. If this is an audible signal carrying a voice or music, for example, a higher signal to noise ratio results in a higher quality audio experience. If you are transmitting data, we say that the data is “cleaner” and subject to less error and variability.
Average Signal Power (S) = SNR
Average Noise Power (N)
This same concept applies to medical equipment, such as functional Magnetic Resonance Imaging (fMRI), used to produce those stunning scans of the brain. The equipment that produces these images must be carefully calibrated, as even tiny fluctuations can compromise the conclusions drawn by neuroscientists. In fact, some experts suggest that signal to noise issues may explain why it is so hard to reproduce the results in many psychology and neuroscience studies, casting a wide shadow of doubt over all research that relies on scanning technologies.
Your Life is Full of Signals – and Noise
And yet, we continue to accept the limitations of our signals, feeding off them, wanting more and more in our lives. Many of us couldn’t make it through a waking hour, much less a day or a week, without the constant stream of data coming to us from our email, our company intranet, and social media. We have simply learned to deal with a certain amount of background noise in order to function in today’s digital environment. Remember, each signal carries with it a certain amount of noise, and the more we crank up the signal, the greater the noise becomes.
So what happens when the signal itself becomes nothing but noise?
Gaiman and McKean’s classic graphic novel, Signal to Noise, explores the battle going on inside our heads between conscious and unconscious, attention and distraction. We now know that your brain has more or less 100 billion neurons, each of which transmits 5-50 “messages” per second. Compare that to the number of tweets transmitted in a single second – 8,436
A Noisy Year
I’ve been thinking a lot about signal to noise lately. It’s been noisy year for me, perhaps for you, too. A signal traveled around the world, telling us that two children died while being held in custody, their parents having made the mistake of hoping that the U.S. would provide a better, safer life for their family than the horrific one they left. A few days later another signal, from the New Horizons probe, declared the staggering achievement of engineering, science, wonder and hope, traveling 4.1 billion miles from Earth to explore an object in the Kuiper Belt, Ultima Thule. You might have expected this accomplishment to be the top story on everyone’s mind on the first day of 2019, but it turns out several college football games and listing of fast food restaurants open on New Year’s Day all generated more Google searches.
More noise, more signal. Who’s to say which is which?
Neuroscience suggests that regular meditation can calm the noise, improve focus and mood, and possibly even ward off dementia. Maybe I’ll give that a try. It’s as good a new year’s resolution as any.