In 2015, Microsoft released a study claiming that the average human attention span had dropped to eight seconds, down from twelve in the year 2000, making us apparently more distracted than goldfish. These findings came out at a time when psychologists, concerned parents, and Boomer pundits had just gotten over the novelty of having internet on phones and were starting to see how it was “destroying” our brains. We were suddenly living in a world where one had to take trips to the Mojave or read long biographies of Winston Churchill to reclaim those four lost seconds.
But a new study suggests that well before the invention of mobile phones, humans were a cognitively distracted species that can only focus on one thing in quarter-of-a-second blocks. This inability to focus isn’t a flaw, but an evolutionary adaptation: Being able to flick between highly focused and diffuse attention gives us the ability to concentrate on a complex task while also being aware of our surroundings, making us the dynamic, hyper-alert creatures that we are today
A team of researchers at Princeton University and the University of California-Berkeley studied the brains of humans and monkeys and found we concentrate in 250 millisecond blocks. The authors of the study use a metaphor to provide a clearer picture of how attention is possible when the bursts are so short: The brain is like a theater with a spotlight and house-lights, and it cycles between spotlight mode (attention focused on a single point on the stage), and house-light mode (attention is diffused over the audience). The constant transition from spotlight to house-lights creates a pulsating, strobe-like effect.
These findings contradict our subjective experience of the world, where attention and perception feel like a continuous phenomenon that persists over minutes, or if we’re lucky, hours. But according to Sabine Kastner, a professor of psychology at Princeton, perception is actually discontinuous, “going rhythmically through short time windows when we can perceive more or less.”
“Attention is fluid, and you want it to be fluid,” lead researcher, Ian Fiebelkorn, said in a statement. “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.”