The noise of life

The experience of noise is fairly mundane for almost everybody: if it is not the traffic on the street or the voices of the neighbors across the wall, it is the surf against the wave breaker, the leaves of the trees rustling in the wind or the birds chirping away. As I pointed out a few months ago, all these sounds are noises as long as they are not the current object of our attention, configuring an audio background for our regular activities that have nothing to do with them. But for a sonar technician trying to identify an enemy vessel, the sound of the propeller is actually the signal they are looking for, whereas a human voice would be noise in the true sense: something that hampers the execution of a measurement or an analysis.

In the last decades however the intentional use of noise has sprouted as a useful way to suppress other unwanted stimuli. The trick lies in having a source of noise with sufficiently high power to fill the audio channel while keeping a the content low enough that it will not draw our attention. This is for instance the case of people who get easily distracted with any noise when trying to fall asleep and use instead a source of white or pink noise that would effectively prevent them from hearing any meaningful sound and therefore being awaken. A similar case has arisen among office workers suffering from an open floor plan: when the blabber of their neighbor makes it impossible to work, the most technologically advanced (and with the deepest pockets) will use headphones with active noise control, but for the rest the alternative is to use the sound of a river, the waves or just a university café as in coffitivity.com (which I occasionally use even if I have an office of my own).

Photo: Tim Ellis

But today I heard the use of the word to label a phenomenon that I have long observed and even mentioned in an article before. Israeli psychologist and Nobel prize winner Daniel Kahneman has recently published a book called "Noise" particularly in reference to the inconsistencies in our judgment: in the example that he presents, one would expect that all the insurance underwriters in a given company would set a similar premium for a given case, because overpricing could lead to losing the client and the opposite would be leaving money on the table. However, in his own investigation he found that the differences between underwriters could be as high as 50% which is a huge discrepancy in the judgment of the risk. Where does this discrepancy come from, considering that the underwriters all have the same actuaries at their disposal to compute the risk? The key to the puzzle is hidden in the differences in the appreciation of each factor by the underwriters.

A similar case happens, unfortunately, in the justice system, where the sentence for a given crime (and even under similar circumstances) not only varies a lot from one judge to the next, but even the same judge can provide significantly different sentences for no apparent reason. It they are hungry, the weather is uncomfortably hot or their team lost their Sunday match they might be inclined to impose a stronger sentence than they would otherwise do. On the other hand, if their spouse smiled at them in the morning, they crossed a puppy on the way to the court or they found a book they particularly like they might be inclined to be more lenient. Of course, this has nothing to do with the defendant's culpability, but it is a (sad) fact of life that all these effects have an impact on this kind of court decisions. Judges are humans after all, and they are subject to the same kinds of influence as anybody else, why would it be otherwise?

As Kahneman self clarifies, the term "noise" only applies to the circumstances where the variability is undesired. In contexts where there is a working mechanism to select the best option variability is not only tolerable but even desirable. This is precisely what happens in the context of genetic evolution or in brainstorming sessions: if all individuals have the same DNA or all the members of the team have the same (kind of) ideas, they will not be able to get away from a complicated situation because a valid solution is just not in their reach. But we have seen that variability alone just does not work and it can be costly.

On a personal note, I have to say that I am strongly aware of my own variability: from food to movie genres, from type of vacation to sitting position on the couch, I know that my taste swings significantly from one day to the next. It is remarkable though, that not every available option is acceptable. For instance, I would never choose to watch a movie about zombies, but one day I could be OK with a historical drama while some other day I would totally prefer to watch some hardcore sci-fi. This variability might sound disorienting but it is certainly a common feature, so rather than fighting against it I tend to embrace it and enjoy the variety that it provides. I know of some people who are very set on their choices (same restaurant, same dish, same drink, same vacation resort) and take some pride in their consistency, but after hearing about Kahneman's book I tend to think that they just do not bother to choose every time and instead pick again the same option that they picked last time. It is very easy but, in my humble opinion, also a bit boring. How about you? Do you embrace the noise in your life or do you curse it? Enjoy your evening.