A new study reveals that how well you’re focusing right now changes how your brain prepares to switch tasks, with surprising consequences for your performance.
Have you ever been so engrossed in a task—so completely “in the zone”—that the world around you seems to fade away? This state of deep concentration, what neuroscientists call sustained attention, is crucial for learning, problem-solving, and getting things done. But what happens when you need to suddenly switch gears? Life rarely allows for uninterrupted focus. We’re constantly pulled between concentrating on one thing and staying ready to react to another. This readiness to shift, known as attentional flexibility, is the other side of the cognitive coin.
For decades, researchers have studied these two pillars of attention, but often in isolation. It raises a fundamental question: how do these two states interact? Does being in a state of deep focus make it harder to switch your attention? Or does being ready to shift your focus at a moment’s notice prevent you from concentrating deeply? A recent study published in Scientific Reports dives into this mental tug-of-war, revealing a complex and fascinating relationship between our ability to focus and our readiness to move on.
A Gaze-Shifting Game to Test the Mind
To explore this dynamic, researchers designed a clever experiment. Participants sat in front of a screen displaying two streams of images, one on the left and one on the right, showing gradually changing scenes of cities and mountains. Their first task was a test of sustained attention: they had to focus on just one stream and press a button every time a city scene appeared, but not for the rarer mountain scenes. The consistency of their response times to the city scenes served as a direct measure of how well they were sustaining their focus. Highly consistent, stable response times meant they were “in the zone,” while erratic, variable times meant their focus was wavering—they were “out of the zone.”
Periodically, the main task would pause. Colored borders would appear around both image streams, cuing the participant to either keep their gaze fixed (a “hold” trial) or shift their gaze to the other stream (a “shift” trial). At the same time, a digit appeared in each stream, and they had to quickly identify the number at the cued location as odd or even. This measured their shift readiness. The twist? The researchers manipulated the probability of these cues. In some blocks of trials, shifts were very likely, while in others, they were rare. This allowed the scientists to see if participants learned to anticipate a shift and how that affected their performance.
Throughout the experiment, an eye-tracker monitored not only where participants were looking but also their pupil size, a well-established proxy for mental arousal. This allowed the team to track three things at once: the stability of their sustained attention, their readiness to shift their gaze, and their moment-to-moment level of arousal.
What They Found: Focus, Flexibility, and the ‘Goldilocks’ Zone
The results painted a nuanced picture of how our attentional systems operate. First, the researchers confirmed a long-standing theory about arousal: the “Goldilocks” principle. Both sustained attention and the ability to hold attention steady were at their best not at low or high levels of arousal, but at an intermediate, “just right” level. When participants were too relaxed (low arousal) or too wired (high arousal), their performance on the focus tasks suffered. This suggests that both deep focus and stability rely on a balanced state of alertness.
Unsurprisingly, participants learned from experience. When they were in a block where shifting gaze was common, the “cost” of shifting—the extra time it took compared to holding their gaze—was significantly lower. Their brains had learned to anticipate the shift and were prepared for it.
The most compelling discovery, however, came from the interaction between sustained attention and this learned readiness to shift. The state of a person’s focus dramatically changed how they used their predictions about the world.
When participants were “out of the zone” (i.e., their sustained attention was poor and their response times were erratic), they became more heavily influenced by their expectations. During these periods of poor focus, an unexpected cue was highly disruptive. For instance, if they were in a block where they expected to hold their gaze, being suddenly asked to shift caused a significant delay in their eye movement. It seems that when our focus is weak, our brain leans more heavily on predictions, and we’re more easily thrown off when those predictions are wrong.
Conversely, when participants were “in the zone” (i.e., their sustained attention was high and stable), something different and equally fascinating occurred. Their strong focus seemed to act as a protective shield, making them less disrupted by unexpected events. The time penalty for an unexpected shift was smaller than when they were out of the zone. However, this highly focused, predictive state had its own downside. When they were in a block where they strongly expected to shift their gaze, they were more likely to make an automatic, unnecessary eye movement to the other side, even when the cue told them to hold steady. It was as if their brain’s preparation to shift was so strong that it sometimes overrode the actual instruction.
Why This Matters for Your Brain
This study elegantly demonstrates that sustained attention and shift readiness are not in a simple trade-off. You don’t just sacrifice one to have the other. Instead, they are distinct processes that influence each other in subtle ways. The state of your focus acts as a modulator, changing how your brain uses learned patterns to guide behavior.
These findings suggest that being “in the zone” does more than just help you concentrate. It may also provide a kind of cognitive resilience, shielding you from the mental disruption of unexpected events and allowing you to disengage from a surprise more quickly. At the same time, it can make your actions more automatic and prediction-driven, for better or for worse.
This research has important implications for understanding cognitive health and disorders. For conditions like ADHD, which is characterized by difficulties with sustained attention, individuals might have an increased reliance on recent trial history to guide their actions, making them more susceptible to the disruption of violated expectations. Understanding this dynamic could open new avenues for therapies and cognitive training. Ultimately, this work reveals the beautiful complexity of the brain’s control systems, which are constantly performing a delicate balancing act to keep us both focused on the task at hand and ready for whatever comes next.
Reference
Gaskins, J. B., Laurienti, P. J., & McClernon, F. J. (2025). Learned saccade readiness varies with fluctuations in sustained attention. Scientific Reports, 15(1), 14340. https://doi.org/10.1038/s41598-025-14340-1
