Permalink : http://hdl.handle.net/2115/42964

KEYWORDS : eye movement;gaze shift;cognitive space;development

Shifting gaze during difficult cognitive activities is a very common phenomenon in our daily life, whereas its underlying neuropsychological mechanisms remain controversial. Preceding studies on adults have indicated that by shifting the gaze people disengage from environmental stimulation in order to concentrate on cognitive tasks. Further studies on children have suggested that approaching this eye movement phenomenon from the developmental viewpoint opens a window on its mechanisms. Here, we used an eye-tracking system to examine eye movements in adults and children while they were performing cognitive tasks, and also employed near-infrared spectroscopy to examine the neural basis of the gaze shift. Adults moved their eyes toward individual specific directions regardless of the task type. In contrast, younger children looked around more extensively with no directionality. Transition to adult-like patterns of eye movements was observed at 10 years of age, which corresponded to the time period of achieving adult levels of performance on a standard measure of executive functions. The eye movements were accompanied by activation of the premotor cortex and/or the lateral prefrontal cortex. These data suggest that the eye movements represent a more positive function than mere disengagement from the environment; probably access to cognitive space. It is also implicated that 10 years of age is a crucial period for cognitive development.