Temporal integration in the perception and discrimination of solid shape

Temporal integration characteristics of an image defined by binocular disparity cues

We can correctly recognize the content of an image by presenting all of the elements within a limited time, such as in a slit view or a divided painting image. It is important to clarify how temporally divided information is integrated and perceived to understand the temporal properties of the information-processing mechanism of visual systems. Previous studies related to this topic have often used two-dimensional pictorial stimuli; however, few have considered the temporal integration of binocular disparity for the recognition of objects defined with disparity. In this study, we examined image recognition properties based on the temporal integration of binocular disparity, by comparing that based on the temporal integration of luminance. The effect of element onset asynchrony (the time lag among presented elements) was somewhat similar between disparity and luminance with respect to randomly divided elements. On the other hand, under slit-vision conditions, the tolerance range of spatiotemporal integration for luminance stimuli was much wider than that for disparity stimuli. These results indicate that the temporal integration mechanism in localized areas is common to disparity and luminance, but that for global motion shows differences between the two mechanisms. Thus, we conclude that global motion has little contribution to the temporal integration of binocular disparity information for image recognition.

Aging and temporal integration in the visual perception of object shape

It has been known for more than 160 years that highly occluded objects that would normally be visually unrecognizable can be successfully identified when they move. This anorthoscopic perception relies on the visual system's ability to integrate information over time to complete the perception of an entire object's shape. In this experiment, 16 younger and older adults (mean ages were 20.5 and 74.6 years, respectively) were familiarized with the (unoccluded) shapes of five naturally-shaped objects (bell peppers, Capsicum annuum) until they could be easily identified (i.e., with accuracies of at least 90 percent correct). All observers then viewed the stimulus objects anorthoscopically as they moved behind narrow slits; only small object fragments could be seen at any given time, because the objects were almost totally occluded from view. Even though the object identification performance for all observers was equivalent when whole object shapes were visible, a large age-related deficit in object identification emerged during anorthoscopic viewing such that the younger adults' identification performance was 45.4 percent higher than that of the older adults. This first ever study of aging and anorthoscopic perception demonstrates that there is an age-related deficit in performing the temporal integration needed for successful object recognition.