Driving under the influence of love can be deadly

Arguing with loved one at wheel 'can affect' driving, experts warn

The driver is weaving in his lane, his speed erratic, and he is clearly distracted. An-other case of texting behind the wheel?

No, he's just got his wife with him.

Confirming what many Canadians have long suspected, a study finds that having a romantic partner in the car is linked to poorer performance on the road. The effects are so powerful, in fact, that people actually drive better while quarrelling with their sweetheart remotely using a hands-free device than when having a neutral in-person conversation with them in the vehicle.

"Emotional distractions are real and can affect your driving," says lead author Terry C. Lansdown. "There's a lot of interest, particularly in North America, in phone distraction. And while there's no doubt that's a serious problem, this shows there's a social component to it as well."

The exploratory study, to appear in a future issue of the journal Accident Analysis and Prevention, is unique in that all participants were romantically linked and all conversations were authentic.

Researchers used a "revealed differences" protocol, wherein participants separately identified and ranked sources of ongoing disagreement in their relationship. The partners' lists were then compared to isolate common causes of conflict, and those topics became the basis of conversation during the simulated driving experiments.

"Previous studies have looked at controlled tasks - counting backward in threes or engaging in increasingly complex mathematical calculations - or at contrived, artificial conversations. That provides experimental control, but it doesn't really reflect the nature of conversations people actually have in cars," says Lansdown, a researcher at Heriot-Watt University in the United Kingdom. "We had people engaging in real conversations that were meaningful to them, in a way they typically would on the road."

Lansdown and co-auth-or Amanda Stephens, of Ire-land's University College Cork, found in-car quarrels affected drivers and non-drivers differently.

Overall, the driver's ability to maintain lane position and speed was "significantly disrupted" when their romantic partner was present, regardless of whether they were having a neutral or contentious conversation. When performance was analyzed, in fact, the best results - i.e. least disruptive - were seen in the remote-quarrel condition (hands-free phone simulation), with the neutral in-person conversation next, and the contentious in-per-son conversation seeing the worst results.

The contentious conversations provoked significant anger in drivers, and were rated as harder to participate in than neutral conversations. And though the presence of a passenger saw poorest road performance, drivers themselves perceived the re-mote exchanges as the most mentally demanding, as well as the most distracting.

Non-drivers, by contrast, were most angered by the re-mote quarrels, which Lans-down says is likely due to not being able to see their partner's reactions. But he says if they're going to argue, it's in their best interest to not be present in the vehicle - or, ideally, to postpone the conversation until off-road.

"Objectively, I presume they'd rather be safe. And if they want to be safe, and for the driver to be safe, they're better off if it's a remote conversation," Lansdown says.

A followup study, currently underway, will apply similar social psychology protocols with parents and their teens.

"We have strong suspicions that they'll be similarly affected in terms of decreases in driving performance."