Itaguchi Y, Yamada C, Fukuzawa K?
Writing in the Air: Contributions of Finger Movement to Cognitive Processing
PLoS ONE 10(6): e0128419.
The present study investigated the interactions between motor action and cognitive processing
with particular reference to kanji-culture individuals. Kanji-culture individuals often
move their finger as if they are writing when they are solving cognitive tasks, for example,
when they try to recall the spelling of English words. This behavior is called kusho, meaning
air-writing in Japanese. However, its functional role is still unknown. To reveal the role of
kusho behavior in cognitive processing, we conducted a series of experiments, employing
two different cognitive tasks, a construction task and a stroke count task. To distinguish the
effects of the kinetic aspects of kusho behavior, we set three hand conditions in the tasks;
participants were instructed to use either kusho, unrelated finger movements or do nothing
during the response time. To isolate possible visual effects, two visual conditions in which
participants saw their hand and the other in which they did not, were introduced. We used
the number of correct responses and response time as measures of the task performance.
The results showed that kusho behavior has different functional roles in the two types of
cognitive tasks. In the construction task, the visual feedback from finger movement facilitated
identifying a character, whereas the kinetic feedback or motor commands for the behavior
did not help to solve the task. In the stroke count task, by contrast, the kinetic aspects of
the finger movements influenced counting performance depending on the type of the finger
movement. Regardless of the visual condition, kusho behavior improved task performance
and unrelated finger movements degraded it. These results indicated that motor behavior
contributes to cognitive processes. We discussed possible mechanisms of the modality dependent
contribution. These findings might lead to better understanding of the complex interaction
between action and cognition in daily life.