The angle of visual roll motion determines displacement of subjective visual vertical

The rod-and-frame effect (RFE) was investigated with the use of a frame that oscillated about an axis at its center at five different frequencies, ranging from .013 to .213 Hz. The resultant RFE shifted continuously with the roll motion of the frame, and it was significantly larger at the lowest frequency (.013 Hz) than under comparable static conditions. The dynamic RFE was lowest at the higher oscillation frequencies. Oscillatory roll vection-apparent self-motion-was reported by 3 of the 9 subjects when the frame was oscillating at its highest frequency (.213 Hz). The subjects yielded large increases in the RFE during the sessions with reports of vection. Surrounding the kinetic frame with a circular contour eliminated all reports of vection and significantly interacted with frequency to reduce the RFE-but only at low frequencies. The reduction amounted to 21.2% averaged over all 9 subjects at the three lowest frequencies. A surrounding contour, therefore, suppressed low-frequency kinetic visual orientation information that might otherwise have produced larger changes in apparent self-orientation and perceived vertical. Vection-sensitive subjects differed from nonvection subjects by exhibiting (1) a high-frequency fall-off in real-motion gain, (2) a high-frequency enhancement in illusory-motion gain, and (3) only a small and nonsignificant increase in illusory-movement phase lag with increases in frequency.

Section: Discussionmentioning

confidence: 97%

Effects of peripheral circular contours on dynamic spatial orientation

Babler

Ebenholtz

1989

“…We did not specifically attempt to measure changes in the subjective vertical in the present study, although both Held et al (1975) and Mauritz, Dichgans, and Hufschmidt (1977) have observed changes in the apparent visual vertical of subjects viewing a rotating visual display in the frontal plane. Our subjects reported their apparent orientation with respect to the subjective gravitational vertical.…”

Section: Discussionmentioning

confidence: 99%

Perceived orientation, motion, and configuration of the body during viewing of an off-vertical, rotating surface

DiZio

Lackner

1986

Dynamic patterns of activity from multiple receptor systems, as well as efferent signals associated with voluntary movements, influence perceived body motion. The experiment to be described explored how these factors interrelate in influencing apparent body motion. It involved exposing stationary, reclining subjects to a patterned surface which rotated around a vertical or an off-vertical axis. We were able to create situations in which the combined patterns of visual, otolithic, somatosensory, and semicircular canal stimulation actually present were not consistent with body motion in a terrestrial environment. Nevertheless, all of our subjects experienced self-rotation and displacement around a vertical axis. A variety of changes in apparent body orientation, body configuration, and slant ofthe visual surface occurred concurrently with the elicitation of apparent body rotation. These perceptual remappings were such as to be consistent both with the rotary visual stimulation present and with the absence of changes in otolithic and somatosensory inputs. They were achieved through a reinterpretation of the static otolithic, somatosensory, and proprioceptive signals present. Our findings demonstrate that perceived body motion also depends on representations of what combinations of sensory input are possible in a terrestrial environment.

“…These weighting procedures have been examined in various studies. When gravitational vertical and the vertical indicated by the visual background are brought into conflict, the perception of a vertical line can be influenced by off-vertical visual frames (Ebenholtz, 1977;Witkin & Asch, 1948) and by off-vertical visual background information (Bischof & Scheerer, 1970;Miiller, 1916), as well as by rotating visual displays (Dichgans, Held, Young, & Brandt, 1972;Mauritz, Dichgans, & Hufschmidt, 1977).…”

mentioning

confidence: 99%

Spatial reference in weightlessness: Perceptual factors and mental representations

Friederici

Levelt

1990

The role of gravity in spatial coordinate assignment and the mental representation of space were studied in three experiments, varying different perceptual cues systematically: the retinal, the visual background, the vestibular, and proprioceptive information. Verbal descriptions of visually presented arrays were required under different head positions (straight/tilt) and under different gravitational conditions (gravity present/gravity absent). The results of two experiments conducted with 2 subjects who participated in a space flight revealed that subjects are able to adequately assign positions in space in the absence of gravitational information, and that they do this by using their head-retinal coordinates as primary references. This indicates that they cognitively adapted to the perceptually new situation. The findings from a third experiment conducted with a larger group of subjects under a condition in which the gravitational information was present but irrelevant to the task being solved (subjects were in a horizontal supine position) show that subjects, in general, are flexible in using cues other than gravitational ones as references when the latter cannot serve as a referential system. These findings, together with the observation that consistent spatial assignment is possible even immediately after first exposure to the perceptually totally novel situation of weightlessness, seem to suggest that the mental representation of space, onto which given perceptual information is mapped, is independent of a particular percept.Perception of, orientation in, and communication about space are some of the most fundamental abilities in human beings. These abilities, which involve the storage and retrieval of spatial information in and from memory, necessarily require the existence of some mental representation or model of space. On the basis of such a mental model, one's perception of, behavior in, and, moreover, communication about space are organized. Unambiguous localization in space necessarily requires a frame of reference with respect to which spatial positions are defined.