Podcasts Won’t Slow Your Driving Reactions, But Phone Calls (Even Hands-Free) Will

Drivers who feel guilty about streaming podcasts during their commute may be worrying about the wrong thing. A new study found that passively listening to audio content produced no measurable delays in how quickly people could move their eyes to spot targets on a screen. Answering questions aloud, however, slowed down eye movement speed and accuracy.

Researchers at Fujita Health University in Japan tested 30 adults as they performed rapid eye movements under three conditions: while answering questions aloud, while listening to audio recordings, and while performing the task with no distractions. Answering questions clearly slowed how long eyes took to move to and settle on targets, and it tended to slow the start of eye movements. Listening looked essentially like no distraction in this task

The laboratory findings suggest a distinction between different types of audio engagement, though whether this translates directly to actual driving scenarios remains to be tested. It certainly raises the question as to whether even hands-free phone conversations could still be considered a form of dangerous distracted driving.

Why Talking Affected Eye Movement Control

What the brain does during talking versus listening makes all the difference. When people listen to audio content, they process incoming information without generating verbal responses, potentially leaving mental resources available for controlling eye movements. Answering questions requires retrieving information, planning what to say, and coordinating the physical act of speech, all processes that may compete with visual attention for brain power.

Research team leader Shintaro Uehara designed an experiment to measure how these different types of audio engagement affect the mechanics of looking. Participants sat in front of a computer screen while an eye tracker monitored their gaze 60 times per second. Their job was simple: move their eyes as quickly and accurately as possible from a center point to a red target appearing in one of eight locations around the screen.

During the talking condition, researchers posed questions requiring thoughtful answers. Some came from standard intelligence tests, asking about factual knowledge like world capitals. Others probed personal memory, asking what participants had worn the previous day or when they had gone to sleep. The researchers used this structured question-and-answer format rather than free-flowing conversation to limit the range of content. For the listening condition, researchers played recordings from a famous Japanese novel and told participants to focus on understanding the content.

How Talking Affected Eye Movement Timing

Three timing measurements captured different phases of the eye movement process. Reaction time measured how long participants took to start moving their eyes after the target appeared. Movement time tracked how long the eye traveled from starting position to target. Adjusting time recorded how long participants needed to stabilize their gaze on the target.

When talking, participants took an average of 280 milliseconds to begin moving their eyes toward the target, about 20 milliseconds longer than while listening or doing the task alone. While this difference was modest, the delays compounded.

Eyes took 260 milliseconds on average to travel to the target while talking, but only 142 milliseconds while listening and 161 milliseconds with no distraction. Nearly double the time.

The most striking difference appeared in stabilization time. Participants needed an average of 1,227 milliseconds to lock their gaze on the target while talking, more than twice the 493 milliseconds required while listening.

Listening and doing the task with no distraction produced virtually identical results across all measurements. Talking stood apart.

Brain Networks and Eye Movement Control

The researchers propose that talking and eye movement control draw on overlapping brain networks, particularly in the frontal and parietal regions. These areas help plan and execute voluntary eye movements toward specific locations. When simultaneously engaged in language production, these networks may have less capacity available for managing precise, rapid eye movements.

The authors note that the listening clips may not have demanded sustained attention in the way real-world audio sometimes does, and they suggest a more demanding listening task could potentially interfere with gaze timing. Participants may not have paid close attention to the novel recordings, which could explain why listening produced no measurable delays.

Earlier brain imaging research offers some support for competition between language and visual control systems. One study using functional MRI found that language comprehension while viewing driving scenes reduced activity in brain areas responsible for spatial processing.

Looking Down Takes Longer

Beyond the talking versus listening distinction, participants consistently took longer to initiate eye movements toward targets in the lower visual field, particularly at positions requiring downward and sideways movements. This downward bias appears in classical vision research dating back decades.

Objects requiring downward gaze carry particular weight in driving scenarios. Children entering the street, animals crossing the road, debris that’s fallen from vehicles, and potholes all require looking below the horizon line. The compound effect of natural downward delays plus talking-induced delays could prove especially dangerous for detecting these hazards.

What the Lab Findings May Mean for Real-World Driving

Visual information provides an estimated 90 percent of what drivers need for safe vehicle operation. Earlier research has established that phone conversations while driving, whether on hand-held or hands-free devices, increase crash risk four times compared to normal driving. The impairment can match or exceed that of driving while legally drunk.

Researchers have typically attributed these elevated crash risks to divided attention and slower physical reactions, such as delayed braking. The new laboratory study points to another possible mechanism: answering questions aloud interfered with gaze timing in this controlled task. One reason the authors pursued this research is that prior driving studies suggest hands-free phone calls can still impair responses, raising questions about how the act of talking might affect early visual steps.

The distinction between listening and answering questions in this controlled laboratory task offers some preliminary observations, though with important caveats. The study tested simple eye movements to clear targets on a screen, not the complex visual demands of actual driving. The listening task may not have required the level of attention that engaging audio content sometimes demands. More difficult or engaging listening material might produce different results.

Answering questions aloud created measurable interference with eye movement control in this laboratory setting. The controlled conditions suggest talking interferes with basic visual motor processes, though how this translates to real roads with their unpredictable hazards remains an open question requiring further research.

Still, the clear distinction between talking and listening in this controlled setting suggests that not all audio engagement carries the same risk. The act of speaking appears to be what interferes with visual control, not just having your ears occupied.