Passenger and cell phone conversations in simulated driving

Drews, F.A., Pasupathi, M., and Strayer, D.L. (2008). Passenger and cell phone conversations in simulated driving. Journal of Experimental Psychology 14(4).

Write about what theory is being investigated

First, the research focuses on the three levels of performance theory, as it pertains to the driving task. The first level of performance is operational or control level performance. This first level involves the task of keeping the car on a chartered course, and when compromised the car will veer or drift. Past studies have shown that talking on the cellular phone while driving impairs operational performance.

The second level of performance is tactical behavior, which "involves skills needed for maneuvering the vehicle in traffic," (Drews, Pasupathi & Strayer 2008, p. 392). Impairment in tactical behavior would mean not paying attention to other drivers, especially when at intersections. Irregular acceleration and slow reaction times are also signs of diminished tactical behavior. Talking on cellular phones while driving has been shown to impair tactical performance.

Strategic performance is the third level, and refers to goals such as navigation. Situational awareness is also part of strategic performance. Research suggests that talking on the cellular phone while driving impairs situational awareness. However, the current research investigates the affect of cellular phone conversations on strategic performance in greater depth.

The current research also investigates the root cognitive causes for attention deficits. The researchers do not seek to show whether cellular phone conversations affect driving performance but why cellular conversations affect driving performance. Attention allocation is the primary theoretical underpinning of the research. Moreover, research has revealed a difference in performance when the driver speaks only with a passenger in the car vs. when the driver is speaking on the phone. Drivers speaking with passengers often perform better, and pay more attention to their surroundings, than drivers who are alone. Drivers who are alone and speak on the phone while driving tend to be the most impaired because their attention resources are misallocated.

Finally, the researchers examine theories of conversation. Conversation demands attention resources, but may in some cases enhance situational awareness. The authors refer to the phenomenon of grounding, in which "all parties in a conversation share relevant knowledge, beliefs, and assumptions," as well as "shared visual attention" cues (Drews, Pasupathi & Strayer 2008, p. 393). Shared awareness theory therefore suggests that drivers with passengers in the car are more likely to be aware of their surroundings then even if they are alone. Driver and passenger become "mutually engaged" the act and experience of driving (Drews, Pasupathi & Strayer 2008, p. 394). Both are paying attention to traffic variables, for example. The content of conversations may also impact the driver's attention, especially when the conversation is held over the phone. In particular, close-call stories are highly likely to impact driving performance. The current research examines whether and why there is a difference between the impact of cellular phone vs. passenger conversations on driver performance.

What is the method? ( include dependent and independent variable, control group, experimental group, description of sample, process, etc.)

Unlike prior research, the current study uses naturalistic conversations. Prior research has relied on simulated conversations, which are usually too artificial to be externally valid. In the current study, 96 participants (48 friend dyads) with valid Utah driver's licenses were tested for vision. Forty-seven participants were female and 49 were male, and although ages ranged from 18 to 49, the average age was 20. Informed consent was provided.

The authors relied on the PatrolSim driving simulator, which loaded a 24-mile multilane beltway "with on and off ramps, overpasses, and two-lane traffic in each direction," (Drews, Pasupathi & Strayer 2008, p. 395). An "irregular flow" setting was used, in which other vehicles changed lanes and speeds. Speed limit in the simulation was 65 mph. The simulation was described as cognitively demanding, requiring the driver to "pay attention to the surrounding traffic," (Drews, Pasupathi & Strayer 2008, p. 395). A familiarization sequence lasted 15 minutes, divided into 3 parts. The three parts included rural night driving, downtown driving, and highway daytime driving. During the familiarization session, one member of each dyad was randomly selected (Drews, Pasupathi & Strayer 2008, p. 395). The participant who was randomly selected as the conversationalist was either assigned to a passenger or a cellular phone situation. Speakers were told to share a "close call" story that they had not shared with the driver before.

There were two distinct sections of the experiment: dual-task and single-task. During the dual-task scenario dyads were conversing either in person or over a simulated phone call. During the single-task there was only driving and no conversation: the single-task scenario serves as the control. The order of the assignments was randomized. In all driving conditions, drivers were given certain instructions on what exit ramp to use. The whole experiment took 60 minutes, but individual driving sequences lasted ten minutes for both single-task and dual-task sections.

What types of measures do they use?

Measures include those involving driving performance and conversation analysis. Driving performance measures include operational, tactical, and strategic measures. Operational measures include "how well participants stayed in the center of the lane without lateral moving or drifting," (Drews, Pasupathi & Strayer 2008, p. 395). Tactical measures included average speed and average following distance (distance between the driver and next car ahead). Strategic performance measures included navigational issues such as whether they took the correct exit.

What is the hypothesis?

The hypothesis is stated on page 393: "the different contexts affect the ability to allocate attention to a task differently…the allocation of attention is not independent of contextual variables, even if the task at the onset seems identical."

The research explores the difference between drivers conversing with passengers and drivers conversing with a person over the phone. The researchers hypothesize that a conversation with a passenger is qualitatively different than a conversation on a cellular phone. The reason for the difference is that attention is allocated differently in phone vs. in-person conversations. The researchers also suggest that driving while speaking with a passenger is relatively safe, whereas driving while talking on a cell phone can lead to an accident.

Conversations were transcribed and analyzed. Although the close-call story was required, the conversations drifted and were analyzed in terms of references to situational variables like traffic. Turn-takes in the conversation were also analyzed. Word complexity, measured by number of syllables per word, was analyzed. The impact of the driving environment, or how demanding the environment was during points of the conversation, was also measured during the conversations.

What are the results?

There was a significant difference in operational performance during the cellular phone conversations, with a "more pronounced tendency to drift," (Drews, Pasupathi & Strayer 2008, p. 397). In tactical performance, no changes in driving speed were noted for each conversational condition. However, following distance was greater during the cell phone conversation. Drivers using cellular phone were four times more likely to fail the navigational challenge.