This is a quasi-experimental study to investigate eye fixation behavior in senile elderly(n=7) and mentally retarded(n=11) groups, in comparison with normal group(n=12). Subjects viewed a series of 8m/m movies of a wayfinding intersection under different conditions such as "basis", "melody", "verbal instruction" and "flashing". The results are summarized as follow: 1) The range of fixations and scan paths in both the senile elderly and mentally retarded group is more limited and biased to the center of presenting figures than that in the control group. Therefore, the senile elderly and mentally retarded group tend to fail to fixate on important visual objects for wayfinding. 2) But, the two groups have the most fixation points and much duration on the traffic signal under "flashing" among the four conditions. 3) Eye fixation behavior of the two groups is enhanced by the visual information being less in number and simplified. 4) Therefore, we infer that the level of visual perception in the senile elderly and the mentally retarded groups can be raised by not only "flashing" of signal but also simplifying the visual information at traffic intersections.
