In daily reality, people often pay attention to several objects that change positions while being observed. In the laboratory, this process is investigated by a phenomenon known as multiple object tracking (MOT) which is a task that evaluates attentive tracking performance. Recent findings suggest that the attentional set for multiple moving objects whose depth changes in three dimensions from one plane to another is influenced by the initial configuration of the objects. When tracking objects, it is difficult for people to expand their attentional set to multiple-depth planes once attention has been focused on a single plane. However, less is known about people contracting their attentional set from multiple-depth planes to a single-depth plane. In two experiments, we examined tracking accuracy when four targets or four distractors, which were initially distributed on two planes, come together on one of the planes during an MOT task. The results from this study suggest that people have difficulty changing the depth range of their attention during attentive tracking, and attentive tracking performance depends on the initial attentional set based on the configuration prior to attentive tracking.

We propose a novel three-dimensional (3-D) display using only two 2-D images displayed at different depths. It is based on a new perceptual phenomenon induced by the human binocular visual system and enables an observer using no extra equipment to perceive an apparent 3-D image of continuous depth when the luminance is divided between the 2-D images according to the 3-D image depth. Our prototype direct-vision 3-D display using this mechanism can easily produce moving 3-D color images by using conventional 2-D color displays.

We investigate the visibility of scrolling text presented nearby a dynamically moving image. In two experiments, we evaluate the subjective speed and readability of scrolled fake addresses presented immediately above a moving grating pattern that covers a large part of the visual field. The drift speed and direction of the grating were controlled to reveal the visibility of the text. The results show that the scrolling addresses exhibited slower subjective speed and better readability when the grating moved in the same direction as the scrolling addresses. On the contrary, faster subjective speed and worse readability of the scrolling addresses were raised by the grating moving in the opposite direction. The strength of these effects was dependent on the speed difference between the scrolling addresses and the grating. These results suggest that the visibility of the scrolling text, assessed in terms of subjective speed and readability, strongly depends on nearby moving images.