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Evidence against an ecological explanation of the jitter advantage for vection.

Palmisano S, Allison RS, Ash A, Nakamura S, Apthorp D - Front Psychol (2014)

Bottom Line: One possible explanation of this jitter advantage for vection is that jittering optic flows are more ecological than smooth displays.Despite the intuitive appeal of this idea, it has proven difficult to test.As expected, the (more naturalistic) treadmill walking and the (less naturalistic) walking in place were found to generate very different physical head jitters.

View Article: PubMed Central - PubMed

Affiliation: School of Psychology, University of Wollongong Wollongong, NSW, Australia.

ABSTRACT
Visual-vestibular conflicts have been traditionally used to explain both perceptions of self-motion and experiences of motion sickness. However, sensory conflict theories have been challenged by findings that adding simulated viewpoint jitter to inducing displays enhances (rather than reduces or destroys) visual illusions of self-motion experienced by stationary observers. One possible explanation of this jitter advantage for vection is that jittering optic flows are more ecological than smooth displays. Despite the intuitive appeal of this idea, it has proven difficult to test. Here we compared subjective experiences generated by jittering and smooth radial flows when observers were exposed to either visual-only or multisensory self-motion stimulations. The display jitter (if present) was generated in real-time by updating the virtual computer-graphics camera position to match the observer's tracked head motions when treadmill walking or walking in place, or was a playback of these head motions when standing still. As expected, the (more naturalistic) treadmill walking and the (less naturalistic) walking in place were found to generate very different physical head jitters. However, contrary to the ecological account of the phenomenon, playbacks of treadmill walking and walking in place display jitter both enhanced visually induced illusions of self-motion to a similar degree (compared to smooth displays).

No MeSH data available.


Related in: MedlinePlus

The general experimental setup. Please note that moving 3-D clouds of spherical objects were used as the visual stimuli for this experiment (not the tiled virtual corridor which is depicted). All room lighting was turned off during the actual testing.
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Figure 1: The general experimental setup. Please note that moving 3-D clouds of spherical objects were used as the visual stimuli for this experiment (not the tiled virtual corridor which is depicted). All room lighting was turned off during the actual testing.

Mentions: The general experimental setup is shown in Figure 1. The computer-generated self-motion displays were generated on a Dell Optiplex GX620 PC and rear-projected onto a flat projection screen (1.48 m wide × 1.20 m high) by a Mitsubishi Electric (Model XD400U) color DLP data projector. The displayed images subtended a visual area of ∼79° wide by ∼67° high and had a 1024 (horizontal) × 768 (vertical) pixel resolution as well as a refresh rate of 72 Hz. Each display (viewed in an otherwise completely dark room) simulated either a 4 or 5 km/h forward self-motion through a 3D cloud of randomly positioned objects. The cloud – the dimensions of which were simulated to be 1.7 m wide by 2.6 m high by 10.8 m deep – consisted of 1000 blue spheres (300 cd/m2) on a black background (0.1 cd/m2). On different trials, these self-motion displays were viewed either while standing still, walking in place, or walking forward on the motorized treadmill (ProForm PF 4.0). Participant head position and orientation were continuously recorded during both types of walking trial, via an ultrasonic Logitech 3-D head tracker (see Ash et al., 2013 for details). For safety reasons, participants wore a ceiling mounted B-Safe body harness throughout the entire experiment (during both walking and standing still blocks).


Evidence against an ecological explanation of the jitter advantage for vection.

Palmisano S, Allison RS, Ash A, Nakamura S, Apthorp D - Front Psychol (2014)

The general experimental setup. Please note that moving 3-D clouds of spherical objects were used as the visual stimuli for this experiment (not the tiled virtual corridor which is depicted). All room lighting was turned off during the actual testing.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4227477&req=5

Figure 1: The general experimental setup. Please note that moving 3-D clouds of spherical objects were used as the visual stimuli for this experiment (not the tiled virtual corridor which is depicted). All room lighting was turned off during the actual testing.
Mentions: The general experimental setup is shown in Figure 1. The computer-generated self-motion displays were generated on a Dell Optiplex GX620 PC and rear-projected onto a flat projection screen (1.48 m wide × 1.20 m high) by a Mitsubishi Electric (Model XD400U) color DLP data projector. The displayed images subtended a visual area of ∼79° wide by ∼67° high and had a 1024 (horizontal) × 768 (vertical) pixel resolution as well as a refresh rate of 72 Hz. Each display (viewed in an otherwise completely dark room) simulated either a 4 or 5 km/h forward self-motion through a 3D cloud of randomly positioned objects. The cloud – the dimensions of which were simulated to be 1.7 m wide by 2.6 m high by 10.8 m deep – consisted of 1000 blue spheres (300 cd/m2) on a black background (0.1 cd/m2). On different trials, these self-motion displays were viewed either while standing still, walking in place, or walking forward on the motorized treadmill (ProForm PF 4.0). Participant head position and orientation were continuously recorded during both types of walking trial, via an ultrasonic Logitech 3-D head tracker (see Ash et al., 2013 for details). For safety reasons, participants wore a ceiling mounted B-Safe body harness throughout the entire experiment (during both walking and standing still blocks).

Bottom Line: One possible explanation of this jitter advantage for vection is that jittering optic flows are more ecological than smooth displays.Despite the intuitive appeal of this idea, it has proven difficult to test.As expected, the (more naturalistic) treadmill walking and the (less naturalistic) walking in place were found to generate very different physical head jitters.

View Article: PubMed Central - PubMed

Affiliation: School of Psychology, University of Wollongong Wollongong, NSW, Australia.

ABSTRACT
Visual-vestibular conflicts have been traditionally used to explain both perceptions of self-motion and experiences of motion sickness. However, sensory conflict theories have been challenged by findings that adding simulated viewpoint jitter to inducing displays enhances (rather than reduces or destroys) visual illusions of self-motion experienced by stationary observers. One possible explanation of this jitter advantage for vection is that jittering optic flows are more ecological than smooth displays. Despite the intuitive appeal of this idea, it has proven difficult to test. Here we compared subjective experiences generated by jittering and smooth radial flows when observers were exposed to either visual-only or multisensory self-motion stimulations. The display jitter (if present) was generated in real-time by updating the virtual computer-graphics camera position to match the observer's tracked head motions when treadmill walking or walking in place, or was a playback of these head motions when standing still. As expected, the (more naturalistic) treadmill walking and the (less naturalistic) walking in place were found to generate very different physical head jitters. However, contrary to the ecological account of the phenomenon, playbacks of treadmill walking and walking in place display jitter both enhanced visually induced illusions of self-motion to a similar degree (compared to smooth displays).

No MeSH data available.


Related in: MedlinePlus