If you worry about your tendency to be distracted and your short attention span, a study that changes the way we look at how our brains focus will make you feel better. Researchers showed in two studies, one on people and one of macaque monkeys, that our ability to pay attention is not like shining a spotlight on something; it's more like looking through a pulsing strobe light.

“Perception is discontinuous, going rhythmically through short time windows when we can perceive more or less,” explained Sabine Kastner of the Princeton Neuroscience Institute in a statement on the work. What that means is that our brains are continuously zooming in and zooming out as we perceive the world. Our attention is always cycling between the trees and the forest, between periods of close focus and a broader, more general awareness of the situation at hand.

We don't experience the gaps in our attention because our brains stream our fragmented perceptions into a coherent movie.

“Attention is fluid, and you want it to be fluid,” Ian Fiebelkorn, the first author on the macaque study, said. “You don't want to be over-locked on anything. It seems like it's an evolutionary advantage to have these windows of opportunity where you're checking in with your environment.”

Robert Knight, a professor of psychology and neuroscience at UC Berkeley and a co-author of the human-focused paper, adds, “It's an elegant way to allocate brain resources — to sample the environment and not have any lapses.”

We don't experience the gaps in our attention because our brains stream our fragmented perceptions into a coherent movie, explained Randolph Helfrich of Berkeley, first author of the human-focused paper.

These rapid shifts of our attention are reflected in the cycling of brain waves. We've known about brain waves since electroencephalograms, or EEGs, were invented in 1924, but no one really understood what the rhythms were for. Says Kastner, the senior author of both papers, “We can now link brain rhythms for the first time to our behavior, on a moment-to-moment basis.”

That the same brain rhythms are seen in non-human primates as well as humans suggests they are quite old and offer an evolutionary advantage. This makes sense when you think about the shifts in attention necessary to successfully hunt for food or navigate a new area.

So the next time your attention wanders, be more understanding of yourself. You still want to avoid distracting your already-active attention and perceptual abilities, however. Mindfulness practices that teach you to note lapses in attention and redirect them can help.

The studies are published in Neuron.