Skip to main content

Why you should stop talking to your car

By Clifford Nass, Special to CNN
June 14, 2013 -- Updated 2058 GMT (0458 HKT)
Commuters move slowly in Los Angeles. Studies show that talking to your car's voice technology impairs driving.
Commuters move slowly in Los Angeles. Studies show that talking to your car's voice technology impairs driving.
STORY HIGHLIGHTS
  • Clifford Nass: More of our brain is devoted to speech than anything else; we love to talk
  • Nass: Talking to technology in your car is not natural and it confuses your brain
  • He says even with hands on wheel and eyes on road, talking to your car impairs driving
  • Nass: Your brain works to fill in the blanks talking to an entity you can't see and doesn't listen

Editor's note: Clifford Nass is the Thomas M. Storke Professor at Stanford University and director of the Communication between Humans and Interactive Media (CHIMe) Lab. He is the author of "The Man Who Lied to his Laptop: What Machines Teach Us About Human Relationships," "Wired for Speech" and "The Media Equation."

(CNN) -- Speaking is profoundly human: More of the human brain is devoted to speech than any other activity. People can have an IQ of 50, or a brain that is only one-third the normal size and have difficulties with many simple tasks, but they can speak.

Humans are so tuned to words that from about the age of 18 months, children learn about eight to 10 new words a day, a rate that continues until adolescence.

Humans love to speak: When two hearing people encounter each other, they will speak, despite having other means of communication such as gesturing or drawing. Even when people speak different languages or come from different cultures, they will try to find common words and phrases.

One-day-old infants can distinguish speech from any other sounds and 4-day-olds can distinguish between their native language and other languages. Even in the womb, a fetus can distinguish her or his mother's voice from all other female voices. Adults can distinguish speech sounds at twice the rate of any other sounds, aided by special hair cells in the outer right ear.

See also: Florida anthropologist explains 'baby talk' origins

Clifford Nass
Clifford Nass
Curbing distracted driving
NTSB: No cell phones while driving

Among all animals, only humans have the necessary breathing apparatus and musculature to be able to speak: despite the "Planet of the Apes," no primate could speak like a person, even if their brains grew. Even human ancestors such as the Neanderthal could not possibly speak: speech is a new and remarkably impressive ability.

So, there is nothing so human as speech -- at least until modern technologies came along. Through striking advances in a computer's ability to understand and produce speech, it is common to use your telephone to make airline reservations, answer questions and search the Web.

Because of the shrinking size and increasing speed of computers, it is also possible to speak directly to your automobile.

From putting up with the car intoning, "Your door is ajar," we have moved to navigation systems that can tell you where to find a latte and car interfaces that understand spoken commands and even allow drivers to dictate e-mails, texts and make phone calls.

What could be more simple and natural than talking, even to a technology? And speaking to cars seems particularly desirable. We don't have to take our eyes from the road or our hands from the wheel to select buttons or make choices: Why not let our mouths and our ears do all the work?

Unfortunately, it's not so simple or so desirable.

Recent research by the AAA Foundation for Traffic Safety, conducted by David Strayer at the University of Utah, finds that the new technology can be so distracting it impairs the ability to drive. Studies found that while driving, our attention becomes overloaded by speaking. It basically takes our minds, if not our eyes, off the road.

Here are three reasons why talking while driving is so distracting, and not as safe and effective as you might think:

People like to picture who they are talking with. When you speak with someone face-to-face, you "hear lips and see voices": Your brain automatically and easily focuses on the person.

When you speak on the telephone, you use brainpower to create a mental image of the person you are talking with: The less you know the person, the more mental workload it takes. When you talk to a car, use a phone in a car or dictate a text message, your brain has to do a great deal of work to picture with whom you are communicating. When you're thinking that hard, it's very difficult to pay attention to the road.

That's why talking on a cell phone -- hands free or not -- is much more dangerous than talking to a passenger. The need to imagine steals from attention to the road.

See also: Is hands-free driving just as dangerous?

People want to be understood. Although people love to speak, there are few more frustrating things than someone not listening. Listeners puts a great deal of energy into showing that they are listening: They nod their head, say "uh huh," open their eyes and change their posture. People are built to expect these signals of attention, but cars refuse to provide them.

As a result, drivers become overly concerned with whether the car understands or is even listening, and their attention is again drawn away from the road. In addition, the voice of the car does not have the rich vocal cues that indicate engagement and emotion, providing further evidence that the car isn't understanding.

Cars are not native speakers. When you encounter someone who isn't facile in your language, you have to put a great deal of time into selecting the right words, avoiding idioms and speaking slowly and clearly. Speech is no longer an easy and natural means of communication in these instances.

While it is remarkable that cars can understand something that took billions of years of human evolution, the typical car recognition rate of 85% to 95% makes it a mediocre second-language speaker. As a result, speech becomes effortful and demanding, stealing attention from the road.

Because of these problems, my laboratory and laboratories around the world are trying to find ways to support the driver in creating mental images, in showing that the car wants to understand and enabling the car to understand at levels equal to or even better than a person.

And soon cars will be driving themselves, so that people can ignore the road and multitask their way to fighting for attention from each other, just as they do outside the car.

Watch: The self-driving car changes everything

Follow us on Twitter @CNNOpinion.

Join us on Facebook/CNNOpinion.

The opinions expressed in this commentary are solely those of Clifford Nass.

ADVERTISEMENT
Part of complete coverage on
October 22, 2014 -- Updated 2101 GMT (0501 HKT)
Paul Callan says the grand jury is the right process to use to decide if charges should be brought against the police officer
October 23, 2014 -- Updated 1619 GMT (0019 HKT)
Theresa Brown says the Ebola crisis brought nurses into the national conversation on health care. They need to stay there.
October 21, 2014 -- Updated 2235 GMT (0635 HKT)
Patrick Hornbeck says don't buy the hype: The arguments the Vatican used in its interim report would have virtually guaranteed that same-sex couples remained second class citizens
October 24, 2014 -- Updated 1336 GMT (2136 HKT)
Paul Begala says Iowa's U.S. Senate candidate, Joni Ernst, told NRA she has right to use gun to defend herself--even from the government. But shooting at officials is not what the Founders had in mind
October 23, 2014 -- Updated 2208 GMT (0608 HKT)
John Sutter: Why are we so surprised the head of a major international corporation learned another language?
October 23, 2014 -- Updated 2154 GMT (0554 HKT)
Jason Johnson says Ferguson isn't a downtrodden community rising up against the white oppressor, but it is looking for justice
October 24, 2014 -- Updated 1621 GMT (0021 HKT)
Sally Kohn says a video of little girls dressed as princesses using the F-word very loudly to condemn sexism is provocative. But is it exploitative?
October 21, 2014 -- Updated 2006 GMT (0406 HKT)
Timothy Stanley says Lewinsky is shamelessly playing the victim in her affair with Bill Clinton, humiliating Hillary Clinton again and aiding her critics
October 23, 2014 -- Updated 1414 GMT (2214 HKT)
Imagine being rescued from modern slavery, only to be charged with a crime, writes John Sutter
October 21, 2014 -- Updated 1600 GMT (0000 HKT)
Tidal flooding used to be a relatively rare occurrence along the East Coast. Not anymore, write Melanie Fitzpatrick and Erika Spanger-Siegfried.
October 21, 2014 -- Updated 1135 GMT (1935 HKT)
Carol Costello says activists, writers, politicians have begun discussing their abortions. But will that new approach make a difference on an old battleground?
October 21, 2014 -- Updated 1312 GMT (2112 HKT)
Sigrid Fry-Revere says the National Organ Transplant Act has caused more Americans to die waiting for an organ than died in both World Wars, Korea, Vietnam, Afghanistan and Iraq
October 21, 2014 -- Updated 1851 GMT (0251 HKT)
Crystal Wright says racist remarks like those made by black Republican actress Stacey Dash do nothing to get blacks to join the GOP
October 21, 2014 -- Updated 2207 GMT (0607 HKT)
Mel Robbins says by telling her story, Monica Lewinsky offers a lesson in confronting humiliating mistakes while keeping her head held high
October 20, 2014 -- Updated 1329 GMT (2129 HKT)
Cornell Belcher says the story of the "tea party wave" in 2010 was bogus; it was an election determined by ebbing Democratic turnout
October 20, 2014 -- Updated 2012 GMT (0412 HKT)
Les Abend says pilots want protocols, preparation and checklists for all contingencies; at the moment, controlling a deadly disease is out of their comfort zone
October 20, 2014 -- Updated 0336 GMT (1136 HKT)
David Weinberger says an online controversy that snowballed from a misogynist attack by gamers into a culture war is a preview of the way news is handled in a world of hashtag-fueled scandal
October 20, 2014 -- Updated 1223 GMT (2023 HKT)
Julian Zelizer says Paul Krugman makes some good points in his defense of President Obama but is premature in calling him one of the most successful presidents.
October 20, 2014 -- Updated 0221 GMT (1021 HKT)
Conservatives can't bash and slash government and then suddenly act surprised if government isn't there when we need it, writes Sally Kohn
October 22, 2014 -- Updated 1205 GMT (2005 HKT)
ISIS is looking to take over a good chunk of the Middle East -- if not the entire Muslim world, write Peter Bergen and Emily Schneider.
October 20, 2014 -- Updated 1300 GMT (2100 HKT)
The world's response to Ebola is its own sort of tragedy, writes John Sutter
October 17, 2014 -- Updated 2033 GMT (0433 HKT)
Hidden away in Russian orphanages are thousands of children with disabilities who aren't orphans, whose harmful treatment has long been hidden from public view, writes Andrea Mazzarino
October 18, 2014 -- Updated 1722 GMT (0122 HKT)
When you hear "trick or treat" this year, think "nudge," writes John Bare
October 18, 2014 -- Updated 0442 GMT (1242 HKT)
The more than 200 kidnapped Nigerian schoolgirls have become pawns in a larger drama, writes Richard Joseph.
October 17, 2014 -- Updated 1345 GMT (2145 HKT)
Peggy Drexler said Amal Alamuddin was accused of buying into the patriarchy when she changed her name to Clooney. But that was her choice.
October 16, 2014 -- Updated 2043 GMT (0443 HKT)
Ford Vox says the CDC's Thomas Frieden is a good man with a stellar resume who has shown he lacks the unique talents and vision needed to confront the Ebola crisis
October 18, 2014 -- Updated 0858 GMT (1658 HKT)
How can such a numerically small force as ISIS take control of vast swathes of Syria and Iraq?
October 17, 2014 -- Updated 1342 GMT (2142 HKT)
How big a threat do foreign fighters in Syria and Iraq pose to the West? It's a question that has been much on the mind of policymakers and commentators.
October 17, 2014 -- Updated 1221 GMT (2021 HKT)
More than a quarter-million American women served honorably in the Iraq and Afghanistan wars. Now they are home, we have an obligation to help them transition back to civilian life.
October 16, 2014 -- Updated 2027 GMT (0427 HKT)
Paul Begala says Rick Scott's deeply weird refusal to begin a debate because rival Charlie Crist had a fan under his podium spells disaster for the Florida governor--delighting Crist
October 16, 2014 -- Updated 0407 GMT (1207 HKT)
The longer we wait to engage on Ebola, the more limited our options will become, says Marco Rubio.
October 15, 2014 -- Updated 1153 GMT (1953 HKT)
Democratic candidates who run from President Obama in red states where he is unpopular are making a big mistake, says Donna Brazile
October 16, 2014 -- Updated 0429 GMT (1229 HKT)
At some 7 billion people, the world can sometimes seem like a crowded place. But if the latest estimates are to be believed, then in less than a century it is going to feel even more so -- about 50% more crowded, says Evan Fraser
October 20, 2014 -- Updated 1653 GMT (0053 HKT)
Paul Callan says the Ebola situation is pointing up the need for better leadership
October 15, 2014 -- Updated 2245 GMT (0645 HKT)
Nurses are the unsung heroes of the Ebola outbreak. Yet, there are troubling signs we're failing them, says John Sutter
October 15, 2014 -- Updated 1700 GMT (0100 HKT)
Dean Obeidallah says it's a mistake to give up a business name you've invested energy in, just because of a new terrorist group
October 15, 2014 -- Updated 2301 GMT (0701 HKT)
Fear of Ebola is contagious, writes Mel Robbins; but it's time to put the disease in perspective
October 14, 2014 -- Updated 1744 GMT (0144 HKT)
Oliver Kershaw says that if Big Tobacco is given monopoly of e-cigarette products, public health will suffer.
October 18, 2014 -- Updated 1335 GMT (2135 HKT)
Stop thinking your job will make you happy.
October 15, 2014 -- Updated 0208 GMT (1008 HKT)
Ruben Navarrette says it's time to deal with another scandal involving the Secret Service — one that leads directly into the White House.
October 14, 2014 -- Updated 1125 GMT (1925 HKT)
Americans who choose to fight for militant groups or support them are young and likely to be active in jihadist social media, says Peter Bergen
October 13, 2014 -- Updated 1303 GMT (2103 HKT)
Stephanie Coontz says 11 years ago only one state allowed same sex marriage. Soon, some 60% of Americans will live where gays can marry. How did attitudes change so quickly?
October 14, 2014 -- Updated 2004 GMT (0404 HKT)
Legalizing assisted suicide seems acceptable when focusing on individuals. But such laws would put many at risk of immense harm, writes Marilyn Golden.
October 13, 2014 -- Updated 1307 GMT (2107 HKT)
Julian Zelizer says the issues are huge, but both parties are wrestling with problems that alienate voters
October 13, 2014 -- Updated 2250 GMT (0650 HKT)
Mel Robbins says the town's school chief was right to cancel the season, but that's just the beginning of what needs to be done
October 11, 2014 -- Updated 1543 GMT (2343 HKT)
He didn't discover that the world was round, David Perry writes. So what did he do?
ADVERTISEMENT