Two studies published recently in the journal Neuron are showing that human attention works differently than we previously thought. Instead of acting like a constant spotlight that directs our focus to something and keeps it there, attention is more like a pulsing strobe light that continually checks the environment to see if there is something more important for us to focus on. This shift takes place about four times per second.
Scientists speculate that this could be an evolutionary adaptation to help protect us. For example, if you focus too much on say a piece of fruit hanging from a tree, you might miss a tiger nearby that could put your life in peril. Your brain gives you an opportunity to shift your focus about every quarter of a second. So you are always rapidly shifting between focus and distraction without really being aware of it.
Both studies used a similar technique. Participants were asked to focus on images on a computer screen. Very faint, almost undetectable rectangle shapes were flashed at random intervals during the experiment. Study subjects were asked to indicate these occurrences by lifting their finger from a mouse button they had been holding down. Electrodes were used to measure neuronal activity and special cameras were employed to detect shifts in attention. The data revealed a regular dip in neuron activity every quarter second. The rhythm, observed in both humans and macaque monkeys, suggest that our brains are regularly giving an opportunity to focus on something different and more important.
Gaining a deeper understanding of how these brain rhythms work could be useful for studying attention deficit disorders. The research team speculated that people who get hyper focused or very easily distracted because of their ADHD might be getting “stuck” in one of the two states of neuron activity described in their papers.
Sabine Kastner, a study author and cognitive neuroscientist at Princeton said “In either case of ADHD, brain rhythms may be disturbed in some way and kids get locked into one state or the other, and not the regular attention processing we see laid out by our study.” She added, “It’s just our hypothesis, but it could be tested in kids or any population with an attention deficit.”
Attention, distraction and the war in our brain: Jean-Philippe Lachaux at TEDxEMLYON