Is There Any Difference between Conversing by Phone and Conversing with a Passenger While Driving?
archive: archived pipeline: cataloged verified
Get this paper ↗ (full text — opens at the source; we link to it, we don't host it)
Summary
This study investigates the cognitive differences between conversing by phone and conversing with an in-car passenger while driving. Motivated by conflicting prior research regarding whether these two secondary tasks impose similar interference on driving performance, the authors sought to determine if phone conversations are more cognitively demanding. The central hypothesis was that phone conversations would exhibit lower speech quality—characterized by reduced fluency and increased disfluencies—compared to passenger conversations, particularly as driving complexity increased. The researchers conducted an on-road experiment on a motorway involving sixteen drivers aged 21 to 50. Participants engaged in naturalistic conversations under three conditions: while the vehicle was stationary, during low-demand driving (straight driving), and during high-demand driving (overtaking or lane changes). Each driver completed two phone conversations and two passenger conversations, initiated by experimenters following standardized discussion guides to ensure consistent interaction levels regardless of traffic conditions. Speech was recorded and analyzed for four indicators: speech rate (words per minute), speech rate including fillers, filler rate (hesitations per word), and repetition rate. Statistical analyses were performed using repeated-measures ANOVAs to compare the effects of conversation type and driving condition. The results demonstrated that phoning was significantly more complex than conversing with a passenger. Drivers exhibited a lower speech rate (words per minute) and higher rates of both fillers and repetitions during phone calls. Specifically, the filler rate was significantly higher for phone conversations across all driving conditions, indicating greater difficulty in maintaining speech flow. Additionally, driving complexity negatively impacted speech quality; speech rates decreased and disfluencies increased when moving from stationary to driving conditions, and further degraded from low-demand to high-demand driving. Notably, while drivers maintained their overall speech delivery speed by increasing filler usage during high-demand driving, their actual word production rate dropped significantly. The findings suggest that phone conversations consume more attentional resources than passenger conversations, leaving fewer resources available for the primary driving task. The authors attribute this to the lack of non-verbal cues and shared situation awareness in phone calls, which forces drivers to compensate for missing social cues and maintain conversation continuity through effortful speech strategies. Consequently, talking on a cell phone likely generates greater interference with driving performance than talking to a passenger, even when the passenger does not actively modulate the conversation based on traffic conditions. This supports the conclusion that auditory tasks requiring active engagement and lacking visual feedback pose a higher risk to driving safety.
Key finding
Phone conversations produced a significantly lower speech rate and higher number of fillers and repetitions than passenger conversations, indicating greater cognitive complexity.
Methodology
on_road
Sample size: 16
Provenance
The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via bulk_ingest_rosap on 2026-05-23 (6 acquisition events logged).
| Stage | Outcome | Tool | Model | Prompt | Attempts | Completed |
|---|---|---|---|---|---|---|
| discover | success | rosap | — | — | 2 | 2026-05-23 |
| archive | success | — | — | — | 1 | 2026-05-23 |
| extract | success | cached | — | — | 2 | 2026-06-10 |
| clean | success | — | — | — | 1 | 2026-06-01 |
| chunk | success | — | — | — | 1 | 2026-06-01 |
| embed | success | — | — | — | 1 | 2026-06-02 |
| enrich | success | — | — | — | 1 | 2026-05-23 |
| promote | success | — | — | — | 1 | 2026-05-23 |
| summarize | success | llm | qwen3.6-27b-prismaquant | summ-v5 | 3 | 2026-06-10 |
| tag | success | vector_similarity | — | — | 19 | 2026-06-11 |
| verify | success | — | — | — | 2 | 2026-06-10 |
Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.
Topics
Ranked by relevance to this paper. Hover a topic for its definition.
Information type
What kind of knowledge this paper contributes, grouped by family — independent of topic (what it is about) and method (how it was studied).
- Empirical Findings: observational prevalence, behavioral performance data
- Theoretical Contribution: theory or model