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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

Horizontal, vertical and depth head position over time for one participant (S2). (A) Plot shows the head position changes (in meters) of this participant while walking on a treadmill at 4 km/h while viewing a matched speed self-motion display. (B) Plot shows head position changes for this participant viewing a similar display (also simulating a 4 km/h forward self-motion) while walking in place.
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Figure 2: Horizontal, vertical and depth head position over time for one participant (S2). (A) Plot shows the head position changes (in meters) of this participant while walking on a treadmill at 4 km/h while viewing a matched speed self-motion display. (B) Plot shows head position changes for this participant viewing a similar display (also simulating a 4 km/h forward self-motion) while walking in place.

Mentions: In the introduction we hypothesized that head jitter amplitudes and frequencies would differ significantly in the “more ecological” treadmill walking and “less ecological” walking in place conditions. Throughout each walking trial, we continuously recorded head position (along the x/horizontal, y/vertical, z/depth axes in m) and head orientation (relative to these same three axes in degrees). In order to test the above hypothesis, we chose to focus only on our participants’ head position changes when walking (because the visual consequences of head position changes could not be ed by eye movements and were more salient than those resulting from head orientation changes). Figure 2 provides examples of the raw horizontal, vertical and depth head position changes made during one treadmill walking trial, and one walking in place trial, for one representative participant (S2).


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

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

Horizontal, vertical and depth head position over time for one participant (S2). (A) Plot shows the head position changes (in meters) of this participant while walking on a treadmill at 4 km/h while viewing a matched speed self-motion display. (B) Plot shows head position changes for this participant viewing a similar display (also simulating a 4 km/h forward self-motion) while walking in place.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Horizontal, vertical and depth head position over time for one participant (S2). (A) Plot shows the head position changes (in meters) of this participant while walking on a treadmill at 4 km/h while viewing a matched speed self-motion display. (B) Plot shows head position changes for this participant viewing a similar display (also simulating a 4 km/h forward self-motion) while walking in place.
Mentions: In the introduction we hypothesized that head jitter amplitudes and frequencies would differ significantly in the “more ecological” treadmill walking and “less ecological” walking in place conditions. Throughout each walking trial, we continuously recorded head position (along the x/horizontal, y/vertical, z/depth axes in m) and head orientation (relative to these same three axes in degrees). In order to test the above hypothesis, we chose to focus only on our participants’ head position changes when walking (because the visual consequences of head position changes could not be ed by eye movements and were more salient than those resulting from head orientation changes). Figure 2 provides examples of the raw horizontal, vertical and depth head position changes made during one treadmill walking trial, and one walking in place trial, for one representative participant (S2).

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