Critical role of foreground stimuli in perceiving visually induced self-motion (vection)

The effects of a foreground stimulus on vection (illusory perception of self-motion induced by a moving background stimulus) were examined in two experiments. The experiments reveal that the presentation of a foreground pattern with a moving background stimulus may affect vection. The foreground stimulus facilitated vection strength when it remained stationary or moved slowly in the opposite direction to that of the background stimulus. On the other hand, there was a strong inhibition of vection when the foreground stimulus moved slowly with, or quickly against, the background. These results suggest that foreground stimuli, as well as background stimuli, play an important role in perceiving self-motion.     

Imagery experts: How do expert abacus operators process imagery?

This study examined how expert abacus operators process imagery. Without imagery instructions a digit series was auditorily presented as one whole number (WHL list) or separate digits (SEP list). RT from offset of the probe to onset of the response was measured. The main findings were as follows: experts showed no difference in RT between the two lists, while significant differences occurred in non-experts; non-experts' RT increased with probed position, while experts' RT was flat if the series size was within their image capacity; experts' RT increased with probed position when the series size was longer than their image capacity, but its rate of increase was smaller than that of non-experts; and the smaller the image capacity, the steeper the slope of the RT function. It was concluded that experts spontaneously encode the digit series into an imaged abacus, while non-experts encode it verbally; that experts directly access the probed position within their image but serially process the verbally coded overflowed part; and that non-experts search the digit series serially.     

On the perception of two successive sound bursts

Summary This paper is concerned with both time perception and the methodology of perceptual psychology. The perception of the pattern of two successive sound bursts was studied by two different methods, i.e., magnitude estimation and phenomenal report. The temporal interval between the bursts was varied from 38 ms to 3394 ms. First, the observer estimated the duration or speed of each pair by a number without modulus. The estimations could not be fitted by a single power function across the entire range of intervals. That is, the exponent changed discontinuously. Next, the observer categorized freely the impressions of all the pairs. The quality of the phenomenon changed at the point where the exponent changed. All the observers arrived at the same three categories expressing the phenomena of the pairs. The boundaries between them corresponded approximately to the intervals of 150 ms and 2000 ms. The pairs in the middle category were often associated with body movements. The other categories also are of a unique nature. Finally, the possibility and the usefulness of employing psychophysical methods and phenomenological methods together is discussed.We are grateful to Professor Y. Umeoka, University of Tokyo, for his constant advice     

Perceived spatial organization of cutaneous patterns on surfaces of the human body in various positions

The perceived spatial organization of cutaneous patterns was examined in three experiments. People identified letters or numbers traced on surfaces of their body when the relative spatial orientations and positions of the body surfaces and of the stimuli were varied. Stimuli on the front or back of the head were perceived with respect to a frame of reference positioned behind those surfaces, independent of the surfaces' position and orientation. This independence may relate to the way in which the sensory apparatus on the front of the head is used in planning action. Stimuli on other surfaces of the head and body were perceived in relation to the position and orientation of the surface with respect to the whole body or trunk (most of which was usually upright). Stimuli on all transverse/horizontal surfaces were perceived with respect to frames of reference associated with the head/upper chest area. These frames were also used for stimuli on frontoparallel surfaces in front of the upper body. These observations may result from the use of "central" frames of reference that are independent of the head and are associated with the upper body. Stimuli on surfaces in other positions and orientations (with two exceptions) were perceived "externally"--that is, in frames of reference directly facing the stimulated surface. The spatial information processing we found may be fairly general because several of our main findings were also observed in very young children and blind adults and in paradigms studying perception by "active touch" and the spatial organization of the motor production of patterns.     

In space, the past can be recast but not the present

We address the relationship between perception and spatial, working memory. Specifically, we argue that perceptual experience following the creation of a representation of target location affects it in a systematic way. We designed a motor task in which observers had to point to the initial or final position of a horizontally drifting target embedded in a vertically drifting background. The target was perceived as having an illusory motion component in a direction opposite that of the inducer dots [Duncker, 1938, Source Book of Gestalt Psychology (London: Kegan Paul, Trench, Trubner and Co)]. For both positions, there was an identical time delay before the observer could respond. Nonetheless, estimates of the initial target position were significantly biased by the illusion in a direction opposite the perceived target motion, and both bias and variability were significantly greater than those of the target's final position. In prior studies on positional accuracy with induced displacement, a delay before a pointing response led to an unbiased position estimate obtained without delay to become biased, leading investigators to argue for a long-lasting, inaccurate cognitive system that overrules an accurate, nonetheless transient, motor one (Bridgeman et al, 1997, Perceptual Psychology 59 456-469). Since the same motor task with identical delay on either position yielded different outcomes, a hypothesis based on distinct motor and cognitive representations of visual space is untenable here. Instead, we argue that an online representation of the target's original position is updated in an ongoing fashion in order to reconcile the perceived illusion with the veridically perceived present (current target location).     

Perceptual organization of moving stimuli modulates the flash-lag effect

When a visual stimulus is flashed at a given location the moment a second moving stimulus arrives at the same location, observers report the flashed stimulus as spatially lagging behind the moving stimulus (the flash-lag effect). The authors investigated whether the global configuration (perceptual organization) of the moving stimulus influences the magnitude of the flash-lag effect. The results indicate that a flash presented near the leading portion of a moving stimulus lags significantly more than a flash presented near the trailing portion. This result also holds for objects consisting of several elements that group to form a unitary percept of an object in motion. The present study demonstrates a novel interaction between the global configuration of moving objects and the representation of their spatial position and may provide a new and useful tool for the study of perceptual organization.     

Ongoing Cross-National Identity Transformation: Living on the Queer Japan-U.S. Transnational Borderland

In this essay, I analyze my border performances of becoming and being as an embodied text to explicate, elucidate, and elaborate culturally hybrid practices of intercultural transition. I pay close attention to unpack the material realities of my hybridity as I continue to live within and beyond queer (or non-heteronormative) Japan–US transnational borderland. In so doing, I aim to illustrate (dis)connections between my identity negotiation processes and the multiple significances of queer Asian/American male identity construction to disrupt the heteronormative modes of thinking about intercultural transitions.     

Mirror-reversal phenomena in the cutaneous perception and writing of children

When a letter is drawn on the forehead, it is perceived cutaneously as a mirror reversal of the experimenter-defined stimulus. An analogous mirror-reversal phenomenon is found in motor behaviour; eg, writing on the downward-facing horizontal surface of a table. We examined these mirror-reversal phenomena in tasks, performed by 4-year-old and 8-year-old children, involving cutaneous perception and motor-production. The children's tendencies toward mirror reversal in the two tasks varied with the orientation and position of the surface, but were similar to those of sighted and blind adult subjects. In addition, mirror reversal was independent of the left-right indifference often observed in young children in writing or visual-matching tasks. The implications of these findings are discussed in the context of a body schema used to guide sensorimotor functions.     

Neon flank and illusory contour: interaction between the two processes leads to color filling-in.

Two aspects of neon color spreading, local color spreading (neon flank) and illusory contour, were investigated by dichoptic viewing. Neon flank was not observed under appropriate dichoptic stimulation, suggesting that input to the process for local color spreading is based on monocular configuration. However, illusory contours were formed according to the interocularly combined configuration rather than according to each monocular configuration, suggesting that input to the process responsible for illusory contours should be ocularly-nonselective and binocular, rather than monocular. The possibilities of artifacts such as those arising from interocular rivalry were appropriately eliminated, and thus, it is tentatively concluded that the process underlying local color spreading is monocularly driven, whereas the process underlying illusory contours is binocularly driven. Furthermore, a new demonstration is presented that indicates that interocularly-induced illusory contours 'capture' and extend the monocularly-induced local color spreading, resulting in global color spreading (neon color spreading). These results support our hypotheses that neon color spreading involves two separable processes in the early visual processing, the feature detection process (for local color spreading) and the illusory contour process, and that these two processes interact with each other at later stages of cortical processing. The relation of local color spreading and illusory contours to surface separation is also discussed.