Prior Exposure to Dynamic Visual Displays Reduces Vection Onset Latency.

While compelling illusions of self-motion (vection) can be induced purely by visual motion, they are rarely experienced immediately. This vection onset latency is thought to represent the time required to resolve sensory conflicts between the stationary observer's visual and nonvisual information about self-motion. In this study, we investigated whether manipulations designed to increase the weightings assigned to vision (compared to the nonvisual senses) might reduce vection onset latency.

Assumed Lighting Direction in the Interpretation of Cast Shadows.

Assumed lighting direction in cast-shadow interpretation was investigated. Experiment 1 used an ambiguous object-shadow-matching task to measure bias in shadow-matching direction. The shadow-matching bias was largest when the lighting direction was on average 38.

Directional Bias in the Perception of Cast Shadows.

Previous studies have demonstrated that the perception of shading is based upon assumptions about lighting direction, for example, light from above. However, it is not clear whether these assumptions are used in the perception of cast shadows. Moreover, it is unclear whether a perceptual interaction exists between shading and cast shadows because until now they have been studied separately.

Perceived gravitoinertial force during vection.

Background: When we ride on a roller coaster, our experience of self-motion is accompanied by salient changes in gravitoinertial force. Here we examined whether a similar relationship exists between visually induced self-motion (vection) and perceived gravitoinertial force.

Methods: There were 15 stationary subjects, each wearing a weight jacket, who were exposed to visual displays simulating upward, backward, or no self-motion.

Evaluation of an organic light-emitting diode display for precise visual stimulation.

A new type of visual display for presentation of a visual stimulus with high quality was assessed. The characteristics of an organic light-emitting diode (OLED) display (Sony PVM-2541, 24.5 in.

Effects of dynamic luminance modulation on visually induced self-motion perception: observers' perception of illumination is important in perceiving self-motion.

Coherent luminance modulation of visual objects affects visually induced perception of self-motion (vection). The perceptual mechanism underlying the effects of dynamic luminance modulation were investigated with a visual stimulus simulating an external environment illuminated by a moving spotlight (the normal spotlight condition) or an inverted luminance version of it (the inverted luminance condition). Two psychophysical experiments indicated that vection was generally weakened in the inverted luminance condition.

Hunger enhances vertical vection.

Hunger was found to facilitate visually induced illusory upward and downward self-motions (vertical vection), but not illusory self-motion in depth (vection in depth). We propose that the origin of this hunger effect lies in the possibility that vertical self-motions (both real and illusory) are more likely to induce changes in visceral state.

Vection modulates emotional valence of autobiographical episodic memories.

We examined whether illusory self-motion perception ('vection') induced by viewing upward and downward grating motion stimuli can alter the emotional valence of recollected autobiographical episodic memories. We found that participants recollected positive episodes more often while perceiving upward vection. However, when we tested a small moving grating or a static grating that produced little or no vection, no modulation of emotional valence was observed.

Vection can be induced without global-motion awareness.

A new vection illusion is reported. Vection was induced even though there was no consciously perceived global display motion corresponding to the self-motion. The resulting experience can be summarised as: "I feel that I am moving but I do not know why".

Vection can be induced in the absence of explicit motion stimuli.

The present study utilized two separate experiments to demonstrate that illusory self-motion (vection) can be induced/modulated by cognition. In the first experiment, two curved lines, which simulated road edges seen while driving at night, were employed. Although the lines induced adequate strength of forward vection, when one of the lines was horizontally reversed, vection was significantly reduced.

The mental number line in depth revealed by vection.

To explore how numbers are represented in depth in our mental space, we asked participants to sequentially speak random numbers while they observed forward/backward vection. We found that participants tended to generate larger numbers when they perceived backward self-motion. The results suggest that numerical magnitudes were topographically mapped onto our mental space from front to rear in an ascending order.

Consistent air flow to the face facilitates vection.

We examined whether a somatosensory cue suggesting forward self-motion facilitated vection. We provided a consistent air flow to subjects' faces by using an electric fan.Vection strength was increased when the air flow was provided.

Inconsistent locomotion inhibits vection.

We measured the strength of illusory self-motion perception (vection) with and without locomotion on a treadmill. The results revealed that vection was inhibited by inconsistent locomotion, but facilitated by consistent locomotion.

Self-motion perception compresses time experienced in return travel.

It is often anecdotally reported that time experienced in return travel (back to the start point) seems shorter than time spent in outward travel (travel to a new destination). Here, we report the first experimental results showing that return travel time is experienced as shorter than the actual time. This discrepancy is induced by the existence of self-motion perception.

Halt and recovery of illusory motion perception from peripherally viewed static images.

We quantitatively investigated the halt and recovery of illusory motion perception in static images. With steady fixation, participants viewed images causing four different motion illusions. The results showed that the time courses of the Fraser-Wilcox illusion and the modified Fraser-Wilcox illusion (i.

Attentional load inhibits vection.

In this study, we examined the effects of cognitive task performance on the induction of vection. We hypothesized that, if vection requires attentional resources, performing cognitive tasks requiring attention should inhibit or weaken it. Experiment 1 tested the effects on vection of simultaneously performing a rapid serial visual presentation (RSVP) task.

Rapid learning by walking observers wearing a reversing or inverting prism.

We measured the initial rapid learning of walking observers who wore an up-down inverting or left-right reversing prism. This prism-walking version of the 'mirror-drawing' experiment revealed that the learning curve as a function of the trial number was the same as that typically acquired from a traditional mirror-drawing experiment. We suggest that the initial short-term learning process involved in prism walking is similar to that in mirror drawing and is related to the high-level decision-making process involved in visuo-motor planning of actions with feedback from transformed vision.

The 'rotating snakes' in smooth motion do not appear to rotate.

'Rotating snakes' is an illusory figure in which the 'snakes' are perceived to rotate. We report that when the image moves smoothly, the snakes do not appear to rotate, although the retinal images are continuously refreshed. Therefore, to produce the illusion, the image should remain stationary (without being refreshed) for some time on the same retinal position.

Inhibition of vection by red.

We investigated the effects of colors on vection induction. Expanding optical flows during one's forward self-motion were simulated by moving dots. The dots and the background were painted in equiluminant red and green.

Static visual components without depth modulation alter the strength of vection.

We conducted a series of psychophysical experiments to investigate the effects of static visual components on visually-induced self-motion perception ('vection'). Static gratings with various spatial frequencies were added to a moving vertical grating, presented either orthogonally or parallel to the motion of the grating. Adding a static component orthogonal to a motion component was found to facilitate vection, whereas adding a static component parallel to a motion component inhibited vection.

Temporonasal motion projected on the nasal retina underlies expansion-contraction asymmetry in vection.

Contracting visual stimuli have been found to induce stronger vection than expanding stimuli. We sought to determine which component of motion underlies the advantage of contraction over expansion in inducing vection. Either the right or left hemi-visual field of an optic flow was presented to either the right or left eye.

Vection aftereffects from expanding/contracting stimuli.

We presented three types of visual stimuli (blank, static and dynamic random dots) following optic flow stimuli and measured the durations of the motion aftereffects (MAEs) and aftereffects of vection (vection aftereffects, VAEs). The VAEs were induced in the direction opposite to the MAEs. However, the VAEs were not the same as the vection induced by the MAEs because the VAEs were sustained even after the MAEs vanished.

Coherent modulation of stimulus colour can affect visually induced self-motion perception.

The effects of dynamic colour modulation on vection were investigated to examine whether perceived variation of illumination affects self-motion perception. Participants observed expanding optic flow which simulated their forward self-motion. Onset latency, accumulated duration, and estimated magnitude of the self-motion were measured as indices of vection strength.

The object and background hypothesis for vection.

Stimulus attributes effective in inducing vection can be generalized by the object and background hypothesis, that is, properties that belong to 'objects' weaken vection while those of the 'background' enhance vection. We presented a motion-defined Rubin's vase to induce vection. Results clearly indicated that the background dominantly induced vection.

Perceptual filling-in of a line segment presented on only one side of the blind spot.

Two experiments examined whether filling-in occurred at the blind spot when a line segment was presented on only one side of the blind spot. We used static and dynamic stimuli: a static test line segment and a pair of probe line segments were presented in Experiment 1 and a moving test line segment was presented in Experiment 2. We compared the probability that the proximal end was perceived to be on the blind spot side when the test line segment came into contact with the blind spot (blind spot condition) with that when the test line segment was outside the blind spot (control condition).