Subject: [NEXTEL-1] MORE COMPLICATED MENTAL TASKS INTERFERE WITH DRIVER

From: [email-masked]
Date: Mon, 30 Jun 2003 20:16:21 -0400

MORE COMPLICATED MENTAL TASKS INTERFERE WITH DRIVERS’ ABILITY TO DETECT AND
DISCRIMINATE AMONG VISUAL TARGETS

Spanish study tested actual highway drivers; also showed hands-free phone
conversations to be as safe – or as risky – as talking to a passenger, depending
on the
demands of the conversation

WASHINGTON — Undertaking complex mental tasks can reduce a driver’s ability to
detect
visual targets by as much as 30 percent. New research on driving in real traffic
confirms that
mental workload can interfere with the capacity to detect visual targets,
discriminate among
them, and select a response. Higher-level mental tasks take attentional resources
away
from the road, resulting in those all-too-familiar post-accident reports: “I
didn’t expect it” or “I
saw it too late.” These findings appear in the June issue of the Journal of
Experimental
Psychology: Applied.

Already knowing that external distractions divert drivers, the authors – at the
Dirección
General De Tráfico, Spain’s Public Administration for Traffic Safety and the
Universidad
Complutense in Madrid -- studied internal distractions produced by the driver’s
own
thoughts or cognitive activity unrelated to the task of driving. “It is easy to
understand how
one cannot see because of not looking,” they explain, “but it is less obvious to
explain how
one looks but does not see.”

The two-psychologist team studied 12 adults who drove for about four hours on the
highway
north from Madrid. They used a standard Citröen with an unobtrusive eye-tracking
system
that allowed them to study gaze and ocular fixation for signs of attention and
distraction as
drivers performed certain mental tasks. Drivers were additionally tested by an
automatic
system that periodically flashed spotlights in the driver’s visual field, to which
drivers
responded using buttons placed ergonomically near the steering wheel. The
researchers
analyzed how drivers scanned the road scene, including use of the speedometer and
mirrors. Researchers also measured how often the drivers glanced at the flashing
spotlights, to identify them before they responded.

The effects of the performance of several mental tasks were compared with the
effects of
ordinary driving (the control condition). After being asked to attend and keep the
information
in mind, drivers listened to recorded audio messages with either abstract or
concrete
information (acquisition task). Next, drivers had to freely generate a
reproduction of what
they had just listened to (production task).

Although the more receptive tasks – listening and learning -- had little or no
effect on
performance, there were significant differences in almost all of the measures of
attention
when drivers had to reproduce the content of the audio message they had just
heard.

Drivers also performed other tasks, either live or by phone. One was mental
calculus
(mentally changing between Euros and Spanish pesetas) either with an experimenter
in the
car, talking to the driver, or with the driver speaking by hands-free phone. One
was a
memory task (giving detailed information about where they were and what they were
doing
at a given day and time). Both tasks produced remarkable distraction effects.

“When performing complex mental tasks,” the authors say, “the percentages of
detected
targets and/or correct responses decreased significantly.” Drivers glanced at the
targets
less frequently, and gave a higher percentage of responses without directly
looking in their
direction. Also during these tasks, the targets (if looked at) were detected later
and glanced
at for less time, which would cause poorer identification.

Say the authors, “Some tasks showed a reduction in detection probability of almost
30
percent with respect to the control condition, something that is practically
meaningful as an
estimate of the increased risk of distraction errors hypothetically leading to
traffic conflicts or
accidents.”

Driver errors appeared to derive from deficient target perception and/or
identification rather
then from a problem with decision rules and/or response performance. In other
words,
mentally distracted drivers still know how to drive, but don’t see things well or
fast enough to
safely use their skills.

In the experimental variation that examined the impact of hands-free phone
conversation,
message complexity made the difference. The relative safety of low-demand phone
conversation -- if hands-free and voice-operated --appeared to be about the same
as that of
live conversation. Thus, the authors say that because they demand too much
attention,
“Complex conversations, whether by phone or with a passenger, are dangerous for
road
safety.” The participants only answered phone calls; the study did not include
dialing.

The authors urge further study to assess the impact of another result, the spatial
gaze
concentration accompanied by a marked reduction in the speedometer and rearview
mirror
inspection, which “can be interpreted as a reduced situation awareness but also as
an
example of a balance to optimize visual resources.”

The results are important, the authors conclude, for “the evaluation of the
potential impact of
in-car devices, the improvement of intelligent vehicle-user interfaces, and the
issue of how
to present information to drivers with minimal interference.”

The findings also confirm that the risk of endogenous distraction (internal to the
driver, as in
complex thought) is at least as relevant as exogenous distraction (external, as in
a crying
child in the back seat or an accident scene on the road).

The authors stress that because distraction cannot be directly submitted to
surveillance and
enforcement, safety measures “such as removing potential external distractors or
restricting
the use of in-vehicle devices, could be effective if users and legislators feel
committed to the
importance of attentional control for road safety.” Without such commitment, they
conclude,
drivers will again adapt and underestimate the importance of attention and the
risk of
distraction, including their own mental activity while driving.

Article: “Mental Workload While Driving: Effects on Visual Search, Discrimination
and
Decision Making,” Miguel Angel Recarte Goldarecena, Ph.D., Universidad
Complutense,
and Luis Miguel Nunes González, Ph.D., Dirección General de Tráfico; Journal of
Experimental Psychology: Applied, Vol. 9, No. 2.

Full text of the article is available from the APA Public Affairs Office.

Reporters: Luis Nunes can be reached by email, through June 5 at this email or
from June
6-July 23 at this email. The cell phone is +34 696 31 21 19. The office phone in
Madrid, c/o
Josefa Valcárcel is +34 91 301 82 38.

The American Psychological Association (APA), in Washington, DC, is the
largest scientific and professional organization representing psychology in the
United States and is the world’s largest association of psychologists. APA’s
membership includes more than 150,000 researchers, educators, clinicians,
consultants and students. Through its divisions in 53 subfields of psychology
and affiliations with 60 state, territorial and Canadian provincial
associations, APA works to advance psychology as a science, as a profession
and as a means of promoting human welfare.

http://www.apa.org/releases/driving_workload.html

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