What is confirmation bias? Its dictionary definition is “the tendency to interpret new evidence as confirmation of one’s existing beliefs or theories”.

You’ve heard this phrase used against you when you were debating with a sibling who have not convinced you to join her side of the worldview divide. With a smirk on her face, she said “OK, now there you are again, citing the news today about so and so, and you say it confirms your theory about human nature. You have confirmation bias.”

How should you respond? I would respond thus: “OK, yeah, that may be, but don’t even pretend that I am the only one with confirmation bias. Everybody does. Even you. Nobody has a monopoly on confirmation bias. What you just said confirms (to me at least) that you have confirmation bias.”

Let’s Do That Again

At a completely different level, though, confirmation bias is another manifestation of how our brains work. We have what I call “resonant brains” and there are just views and feelings that resonate with us and those that don’t.

A resonant device is something that has a resonant vibration, a natural frequency. For example, a guitar string or a bottle has resonant vibration. Certain physical characteristics of the device determine its natural frequency: for the guitar string, it’s the length of the string, the tightness by which it is strung, and its mass (per unit length). When you pluck the string, it absorbs the energy released by the plucking and emits that energy most efficiently at the resonant frequency.

The details of how resonant vibration happens are well understood. When you pluck the guitar string, the string vibrates and the vibration propagates along the string in both directions. When the vibration reaches a post on one end of the string, two things happen: first, part of the energy is transmitted to and amplified by the wooden body of the guitar and that’s how we hear the vibration; second, the string is restrained by the post and therefore the vibration is reflected off that post, like a beam of light that is reflected off a mirror. The same thing happens at the other end of the string and so the two separate reflections get mixed up. Depending on how long the vibrational “wave” has to travel from one end of the string to the other, only one dominant frequency quickly survives, which is the resonant frequency or tone. Just as quickly, there are standing waves that form along the length of the string: the standing wave for the dominant frequency which goes the whole length of the string, a higher but weaker tone with half the length of the standing wave for the dominant frequency, a still higher but weaker tone with one-third the length of the dominant standing wave, and so on. The mixture of these tones impart a distinct quality to the sound that the string generates, one that we can’t mistake for any other instrument.

It is the bouncing of the wave off of the two posts that is of keen interest here.

Our Highly Resonant Brains

We already know that there are layers of neurons in the brain. There are signals that travel from one layer to the next and there are feedback signals going the opposite way.

(sorry I have run out of time; to be continued)