It is also clear, as the busy-building weavers remind us, that while success or failure in the energy quest will always shape the evolutionary trajectory of any species, many hard-to-explain animal traits and behaviors may well have been shaped by the seasonal overabundance of energy rather than the battle for scarce resources, and that in this may lie a clue as to why we, the most energy-profligate of all species, work so hard.

For some anthropologists, most notably Louis Liebenberg, an accomplished tracker himself, the tracks in the archaeological and fossil records are clear. He is of the view that Homo erectus must have hunted in this way and that this form of hunting must also have played a part in making us bipedal—in molding our bodies for long-distance running, in developing the ability to cool our bodies with sweat, and adapting our minds to the challenges of inferring meaning from this, the most ancient form of writing.

But it is an archaeological site called Sunghir, discovered in the 1950s on the muddy banks of Klyazma River on the eastern fringes of the Russian city of Vladimir, that hints at how these populations busied themselves while waiting for the worst of winter to pass. Included among the stone tools and other more conventional bits and pieces, archaeologists there discovered several graves. None were more remarkable than the elaborate shared grave of two young boys who, sometime between 30,000 and 34,000 years ago, were buried together alongside a straightened mammoth-tusk lance in clothing decorated with nearly 10,000 laboriously carved mammoth-tusk beads, as well as pieces including a belt decorated with teeth plucked from the skulls of over a hundred foxes.

With archaeologists estimating it took up to 10,000 hours of work to carve these beads alone—roughly equivalent to five years’ full-time effort for one individual working forty hours a week—some have suggested that these boys must have enjoyed something resembling noble status, and as a result that these graves indicate formal inequality among these foragers. It is at best tenuous evidence of institutional hierarchy; after all, some egalitarian foraging societies like the Ju/’hoansi made similarly elaborate items. But the amount of time and skill involved in manufacturing the mammoth beads and other items suggests that, like the indigenous people of the Pacific Northwest, the annual work cycle for them was seasonal and that in the winter months people often focused their energies on more artistic, indoor pursuits.

To foragers, change was immanent in the environment—it happened all the time, when the wind blew, the rain fell, or an elephant cleared a new path. But change was always constrained by a deeper sense of confidence in the continuity and predictability of the world around them. Every season was different from those that preceded it, yet these differences always fell within a range of predictable changes. Thus for the Ju/’hoansi, when they were still free to forage as their ancestors had, carrying the weight of history was as inconvenient as carrying a house around, and abandoning the deep past freed them to engage with the world around them unencumbered by ancient precedents or future ambitions.

This cognitive ability to remember the past and anticipate the future is one reason some of us feel so busy—not because of the number of tasks we have to complete in the day, but because of the sheer number of things competing for our attention. What is commonly called “distraction” is probably better understood as overstimulation.

Recent findings in neuroscience have shown that our conscious minds cannot do more than one thing at a time. It may feel like you are able to multitask and think about two (or more) things at once, but really your mind is switching between them. This is a costly process neurologically speaking. Switching from one task to another takes energy and a measurable amount of time. Then, when we switch back, it takes another period of time to really wrap our minds around the original object of attention. And it’s not only about the time cost; it’s about the quality of our attention. If we are always switching from one thing to another, then we are never able to truly focus and experience the pleasure and effectiveness of a focused mind. Instead we live in a state of constant recalibration, or what the writer Linda Stone perceptively calls “continuous partial attention.”

Human awareness is not the speedy, nimble creature some of us believe it to be. Our brains have evolved to be more like owls than hummingbirds: we notice something, turn our attention to it, and focus in. It is in this state of intense, solitary focus that we are in possession of our most uniquely human and powerful mental faculties. When we focus on one thing, we are at our most thoughtful, creative, and productive.

But in the screen-heavy environment of the twenty-first century, our mind-owls, large and unwieldy, are treated like hummingbirds, and they end up flopping ineffectively from one thing to the next. Doing this day in and day out accommodates us to what is actually an unnatural, anxiety-producing mode in which the mind struggles to find nourishment.

Which owl is going to feel busier, the one focusing on the sound of a mouse in the snow, or the one trying to draw tiny bits of nectar from a thousand flowers? And which owl is going to be, in the end, better nourished?