How Talking Slows Eye Movements Behind the Wheel
hubie writes:
New study shows that everyday conversations can delay eye movements, essential for safe driving:
Talking while driving is widely recognized as a major source of distraction, but the specific ways conversation interferes with the earliest stages of visual processing have remained largely unclear. While previous research has shown that cognitive distraction can slow braking or reduce situational awareness, the question of whether talking disrupts the foundational gaze processes that precede physical reactions has remained unanswered.
Now, researchers from Fujita Health University have demonstrated that talking imposes cognitive load strong enough to delay essential eye-movement responses, potentially affecting the fast visual assessments required for safe driving. A study led by Associate Professor Shintaro Uehara and the team, including Mr. Takuya Suzuki and Professor Takaji Suzuki, published online on October 6, 2025, in PLOS ONE, examined how talking alters the temporal dynamics of gaze behavior.
Gaze behavior is especially significant because approximately 90% of the information used for driving is acquired visually. Any delay in initiating or completing eye movements can cascade into slower recognition of hazards, reduced accuracy of visual scanning, and delayed motor responses. "We investigated whether the impact of talking-related cognitive load on gaze behavior varies depending on the direction of eye movement," explains Dr. Uehara.
[...] The authors note that their findings do not imply that talking is the sole or dominant cause of slowed physical reactions behind the wheel. Driving performance is influenced by multiple cognitive and perceptual factors, including inattentional blindness, divided attention, and the broader interference that occurs when the brain is forced to manage two demanding tasks at once. Even so, the study demonstrates that talking introduces delays at the earliest stage of visual processing before recognition, decision-making, or physical action, which means it may quietly undermine driving performance in ways that are not immediately obvious to drivers themselves. "These results indicate that the cognitive demands associated with talking interfere with the neural mechanisms responsible for initiating and controlling eye movements, which represent the critical first stage of visuomotor processing during driving," concludes Dr. Uehara.
These insights carry meaningful implications for public safety. By understanding that the cognitive effort involved in conversation can degrade gaze accuracy and timing, drivers may become more mindful about when and how they choose to talk while driving. Over time, this knowledge could support safer driving behaviors, inform driver-training frameworks, inspire improvements in vehicle interface design, and guide policymakers in shaping future recommendations around cognitive distraction.
Journal Reference: Suzuki T, Suzuki T, Uehara S (2025) Talking-associated cognitive loads degrade the quality of gaze behavior. PLoS One 20(10): e0333586. https://doi.org/10.1371/journal.pone.0333586
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