Role of Inhibition Functions in Elderly
Drivers’ Pedal Misapplication
Takahiko Kimura (Faculty of Health and Welfare, Kansai University ofWelfare Sciences)
Kazumitsu Shinohara (School of Human Sciences, Graduate School of
Human Sciences, Osaka University)
This document is based on the following research presentation.
Kimura,T., and Shinohara,K. (2012). Pedal misapplications by older drivers induced by difficulty with inhibition function.
Proceedings of 4th Automotive User Interferences and Interactive Vehicular Applications, 269－272
https://dl.acm.org/citation.cfm?id=2390301

Main Contents of This Study☞ Evaluating and Comparing Cognition Functions of Younger andOlder People☞ Focus on “inhibition functions” among cognitive functions• Multiple number of tasks executed for evaluating inhibition
functions☞ Results• Differences in inhibition functions ofyounger and older people• Older people tend to face difficulties with inhibition• Possibility suggested that accelerator/brake pedal misapplication
may be related to cognitive functions☞ Importance of development of method of evaluating inhibition
functions and education and training related to driving

Awareness of the Issue (1): Relationship between
pedal misapplication and cognitive functions
One cause of occurrence of pedal misapplication☞ Unable (it is difficult) to execute evasive action when it is foundthat a “mistake” has been made(Example) Possibility of stepping on the accelerator!
→ Stop stepping on the accelerator and move the foot awayfrom it.
(avoidance of mistake)→ Continue stepping on the accelerator, not stopping the act.
(occurrence of a mistake)Awareness of the Issue (2): Difficulty instopping the act and recognizing the issue.
Stopping the act = Inhibition↓
One of the cognitive functions known in psychology“Inhibition function”
It is a function related to the control of behavior, and in thisstudy, it refers to stop (inhibit) executing a certain
decision/action and executing a different decision/action.
↓Focus on the differences in the inhibition function of the younger
and older people, and make comparisons

Evaluation of the Inhibition Function☞ Simon Task (Simon, 1990)☞ Stroop Task (Stroop, 1935)☞ Stop Signal Task (Verbruggen, Logan, and Stevens, 2008)

Simon Task
Inhibition task using spatial information(Example) ■ = left, ■ = right☞ Response mapping forms “left.”☞ ■ may sometimes be displayed on the right side (see thefigure below)☞ If spatial information and response mapping are incompatible,inhibition is necessary.
Inhibition required
Processing based on spatial
information (displayed on theright side)
Processing based onresponse mappingThis is faster.

Activation ofresponse

Execution ofthe reaction

Result of the Simon Task

Suggests that inhibition is more difficult for older people

Stroop Task
The “color of the written character” and the “meaning of the writtencharacter” are incompatible.
Color of the character: 赤 (red) → blue
Meaning of the character: 赤 (red) → red☞ Because the meaning of the character is activated, it isnecessary to inhibit the “meaning” when answering for the “color.”
赤 (red)This is faster.
Meaning of the written
character赤 (red)Color of the ink
青 (blue)

Inhibition
Activation oftheresponse

Execution ofthe reponse

Result of the Stroop Task

The Stroop effect is larger for older people, but differences are notseen in the inverted Stroop effect.

Pedal Operation Task
Pressing the appropriate pedal required
when the rectangle expands
BrakeAccelerator

If stopping does
not occur evenwhen steppingon the pedaling
when therectangle has
expanded

Necessary to release that pedal
and step on the other pedal

Results of the Pedal Operation Task
RT 1: Reaction time until the first pedal is pressed
Release time: Time for moving the foot away from the first pedal
RT 2: Reaction time until the next pedal is pressed

In either case, it took longer for the older people than the younger people.

Discussion
Results indicated that there are differences in the inhibition function
between younger and older people.

The relationship between driving an automobile and the executivefunction has also been shown in the previous studies (Pollard andSussman, 1989; Freud at al., 2008; Lococo et al., 2012)↓It is thought that the inhibition function taken up in this study also
reflects the executive function.

Future research(1) Education and training for understanding the changes in theinhibition function and applying that to driving are sought.

(2) It is necessary to study the development of screening methods
with regard to changes in the inhibition function.