Section 4.1. Hacks 44-52

4.1. Hacks 44-52

Your ears are not simply "eyes for sound." Sound contains quite different information about the world than does light. Light tends to be ongoing, whereas sound occurs when things change: when they vibrate, collide, move, break, explode! Audition is the sense of events rather than scenes. The auditory system thus processes auditory information quite differently from how the visual system processes visual information: whereas the dominant role of sight is telling where things are, the dominant role of hearing is telling when things happen [Hack #44] .

Hearing is the first sense we develop in the womb. The regions of the brain that deal with hearing are the first to finish the developmental process called myelination, in which the connecting "wires" of neurons are finished off with fatty sheaths that insulate the neurons, speeding up their electrical signals. In contrast, the visual system doesn't complete this last step of myelination until a few months after birth.

Hearing is the last sense to go as we lose consciousness (when you're dropping off to sleep, your other senses drop away and sounds seem to swell up) and the first to return when we make it back to consciousness.

We're visual creatures, but we constantly use sound to keep a 360° check on the world around us. It's a sense that supplements our visual experiencea movie without a music score is strangely dull, but we hardly notice the sound track normally. We'll look at how we hear some features of that sound track, stereo sound [Hack #45], and pitch [Hack #46] .

And of course, audition is the sense of language. Hacks in this chapter show how we don't just hear a physical sound but can hear the meanings they convey [Hack #49], even on the threshold of perception [Hack #48] . Just as with vision, what we experience isn't quite what is physically there. Instead, we experience a useful aural construction put together by our brains.

We'll finish up by investigating three aspects of understanding language: of the hidden sound symbolism in words [Hack #50], of how we break sentences into phrases, [Hack #51], and of how you know excalty waht tehse wrdos maen [Hack #52] .