Campus: CSU Long Beach -- September 3, 2004
Cell Phone Use Study by Cal State Long Beach Professor Finds
Older Adults Have More Difficulty Driving While Using Cell Phones
A recently completed Cal State Long Beach study on the use of cell phones while
driving has shown, and not surprisingly, that the response time for all drivers is
seriously slowed, but the slowing for older individuals is much more significant
than younger adults.
Overseen by CSULB Psychology Professor Joellen Hartley, the study was conducted
by students who worked with 18 older (65 years of age and older) and 18 younger
(18-30 years of age) subjects. Participants were not required to actually drive
a car for this particular study. Instead, the experiment was done using computers
and simulated scenarios.
"We were looking at the differences between older and younger people and the
effects of the intensity of a cell phone conversation on their performance of a
driving task," Hartley said.
In two of the three scenarios, participants were involved in actual cell phone
conversations and asked to respond to information on the computer screen directly
before them. Their attention and decision-making processes were then evaluated
by the speed and accuracy of their responses.
"What we found was that the older people are slower," noted Hartley, who was not
surprised by that finding alone. "They almost always are. But, as soon as cell
phone conversations were introduced into the process, the response time for both
age groups was really lengthened, and much more so for older adults than for
Identified keys on the computer keyboard were related to gas and brake pedals and,
per prior instruction, participants responded in different ways to color and
position of signals on the screen. More specifically, the evaluation was based on
how long it took to press a key designated as the gas pedal, how long it took to
lift their finger from the same key, and then how long it took them to press one
of two other keys (brake pedals) when the signal changed color yet again.
"Really, two things were happening," said Hartley. "The subject's attention had
to be engaged on the screen to detect changes in the display and then they had to
make a response decision based on what was on the screen. So we were looking at
both attention and decision-making processes by measuring how long it took the
person to respond to something that happened and how long it took them to press
the correct key."
Prior to the actual experiment, participants were allowed to practice until they
were comfortable with the process. The exercise involved participants talking on
cell phones with student assistants. A hands-free device was used to rule out
difficulties holding the phone while doing the task. One conversation was of low
intensity, and the other was high intensity. The latter scenario theoretically
requires the use of more mental resources to manipulate and update information
and come up with a response, Hartley explained. The final test involved no cell
phone conversation with participants just completing the task.
"Where the major effects were seen, for both age groups, was not so much in the
time to make a complex response decision, but on the time needed to grab the
subject's attention." said Hartley. "For the older participants, for example, in
the high intensity conversation, the amount of time needed to grab their attention
(i.e., taking their finger off the gas pedal) was increased by almost 250 percent.
For the younger participants, the increase was nearly 150 percent."
In addition to reacting more slowly under more intense scenarios, Hartley noted
that the elderly participants were more prone to making errors.
"Where we see that decision processes are affected is when we look at the errors,
the mistakes they make when they finally do respond," said Hartley. "The
difference between the young and the old in decision accuracy in the absence of a
cell phone conversation was not significant, but as soon as a cell phone conversation
was introduced, the accuracy for the older people dropped. In younger people
accuracy did not decline until they were involved in high intensity conversations,
but even then only a little.
"So, in a nutshell," Hartley concluded, "cell phone conversations divert attention
from changes in a visual display and interfere with the accuracy of a decision.
Young adults are not immune to these effects, but older adults are much less able
to cope with the demands that a cell phone conversation makes on attention. The
implications for driving safety are obvious."
Media contacts: Rick Gloady, 562/985-5454, Shayne Schroeder,