There is a very specific, almost euphoric feeling when you hear a song for the first time, and we’re quickly trying to digest every little moment in it. The intricate details, the vocal changes, the specifics - the good stuff- are almost impossible to get.

And there was a time when that experience would happen almost exclusively on the radio or the music channels on TV. And the waiting period between the first time hearing it and the second could be hours or days.

Now we can hit replay, repeat, and make the song part of our personality.

But what do you get from the second listen that you don’t get from the first?

There is a fine line between something boring and the predictability that gives us a dopamine rush. If the song sounds the same the whole way through - no drops, no pockets, no hooks or changes, our brains just tune it out. As we listen, our brains map the music based on everything we have ever heard. So when a track does something we aren’t expecting, in just the right way, the emotional payoff is almost disproportionately large.

The core mechanism is a positive reward (dopamine) prediction error (when it does something we weren’t expecting).

So why does the second listen achieve what the first doesn’t?

Mapping as you listen is already very cool. But the second listen gives your brain something the first didn’t. We spend much of the listening time the first time trying to tune in, more than we typically do. The second time, we’re not building the map from scratch; we’re heavy into the anticipation and pattern recognition.

We know what is coming, the broad strokes of the music are there, and we can recall it from the first listen. The first time we are trying to predict, the second time we are anticipating. The emotional feeling has also changed, because now you can’t wait to hear the beat drop or the insane vocals - or a particular riff. During the second listen, the dopamine surge comes ahead of the crescendo, so we get a lot more of it.

At a certain point along the learning trajectory, familiarity starts to set in, the prediction error reduces to almost zero, and the reward for that diminishes. The familiarity of anticipating still says the same thing: you know it is coming, and you wait for it. And while all of that is going on, with each listen you find something new in the music - because you’re fully tuned into it - because you know it.

Then the death or eternal life happens to the song.

Our brains typically prefer something complex, a little less predictable - it gives us more prediction errors to hook into in the first place, and stays interesting after. Pop tracks often have very simple melodies and hooks, which means they are mapped and done pretty quickly. By the end of the first half, your brain has worked it out, and your brain has nothing left to do.

When a track is dense and thick with layers, like a metal track, or switches flow like a rap song, your brain understands it, but the mapping process takes longer. Those details tucked away start to come forward, listen after listen. And if you switch from speakers to headphones, or the other way around, those production details sound different. The music unfolds differently.

The tracks and even albums that feel like you could happily listen to them every day forever are usually more complex. Nuance or double (or more) entendres, unusual pitches, glitches, and drags, loudness in the right place - they become inexhaustible.

If you’ve been with us a while, you know that we always recommend listening to the same song more than once and on different media. We’re not saying it for fun (although it is fun), we’re saying it because it matters to your brain.

The brain region at the center of all of this is the nucleus accumbens. It operates in constant conversation with the auditory cortex, which stores everything you have ever heard - very cool. When a new track arrives, the auditory cortex pulls up similar-sounding templates to generate predictions. When those predictions are met or exceeded, the nucleus accumbens fires.

Researchers at McGill University wanted to measure this properly. Not with self-reported enjoyment or rating scales. They gave participants real money and asked them to bid on tracks they had never heard before. The nucleus accumbens activity during the first listen predicted exactly which tracks they would spend on. The brain had already assigned value before the person consciously knew what they thought of the song. It gets more complicated, so if you like music and brain stuff, click the link to the study; it makes for an interesting read.

Musical pleasure is not passive. It is the ongoing negotiation between what your brain expects and what it actually hears. Every time a track surprises you well, every time a section or note lands better than predicted, that is the reward system doing its job.

Run it back. Your brain is not done yet.

Need some tracks that offer it? We gottem.