Opinion – Suzana Herculano-Houzel: We are attracted by novelties

Everything that is unusual, unexpected, or salient in some way draws our attention. And it’s not the fault of the modern world we live in, full of things happening, windows open on the computer, images popping up on television: even in the quietest of fields, sudden movement in the bush equally attracts the gaze of humans resting and quadrupeds grazing.

Part of the reason—if there is premeditated finalistic reason in the brain’s machinations, which I doubt, but I write “reason” as a shortcut for “immediate mechanistic cause”—is that what the brain registers is not what it is or is, and yes what happens to be. If it were possible for us to paralyze our eyes, really paralyze them — because the eyes that we think are still moving continually — the image would disappear before our eyes. There is always an image formed by the eyes because the eyes always move.

Likewise, what suddenly moves independently of the eyes gains priority processing by the brain, also called attention. What already is contains no more information than when it came to be, and therefore is irrelevant in the face of any novelty. Novelty is what happens to be, above all in an unexpected, unpredictable way. The gift hidden by the wrapping that doesn’t deliver its contents. The new song Spotify bets you’ll enjoy. Oh, how we like news.

After the surprise, the brain’s reward system registers the novelty and rewards the experience with a surge of dopamine that sets in motion the circuits that make us feel pleasure, however they work: to this day we don’t know how to describe what, exactly, in the body is this damn sensation of pleasure.

But what makes us anticipate novelty and act in pursuit of it, actively increasing our chances of exposure to what is new?

A study published in the most recent issue of the journal Nature Neuroscience, by a group of researchers at Washington University, in Saint Louis, USA, shows that the attraction to novelty is the work of a region of the brain whose name could not be more appropriate: the uncertain zone.

If the name simply comes from the original uncertainty about the function of this tiny part of the brain, squeezed between the thalamus and the midbrain, it now justifies itself: the activity of neurons in this region, governed by visual stimuli, signals the immediate or imminent presence of novelty. —and those same neurons make the midbrain, right there on the side, organize eye movement towards novelty.

No wonder, these are the same neurons in the midbrain that respond to that sudden movement of the weeds and move our eyes there, which gives us a high-resolution image of what is about to happen. When the brain alone predicts that something new should appear there, even though nothing has moved (yet), the uncertain zone turns expectation into action.