Jitter and Size Effects on Vection are Immune to Experimental Instructions and Demands

Abstract

Both coherent perspective jitter and explicit changing-size cues have been shown to improve the vection induced by radially expanding optic flow. We examined whether these stimulus-based vection advantages could be modified by altering cognitions and/or expectations about both the likelihood of self-motion perception and the purpose of the experiment. In the main experiment, participants were randomly assigned into two groups-one where the cognitive conditions biased participants towards self-motion perception and another where the cognitive conditions biased them towards object-motion perception. Contrary to earlier findings by Lepecq et al (1995 Perception 24 435-449), we found that identical visual displays were less likely to induce vection in 'object-motion-bias' conditions than in 'self-motion bias' conditions. However, significant jitter and size advantages for vection were still found in both cognitive conditions (cognitive bias effects were greatest for non-jittering same-size control displays). The current results suggest that if a sufficiently large vection advantage can be produced when participants are expecting to experience self-motion, it is likely to persist in object-motion-bias conditions.

Vertical illusory self-motion through haptic stimulation of the feet

“…It has been shown [9,6,14] that both circular and linear vection may be influenced by whether participants are seated in a chair that potentially could move as opposed to one that is immovable. It has also been shown that vection under some circumstances may also be influenced by whether the participants are asked to attend to the sensation of selfmotion or objects' motion before being subjected to visual motion stimuli [5]. Notably, illusory self-motion may also be induced auditorily during deprivation from visual stimuli [12].…”

Attentional load inhibits vection

“…In addition, Lepecq, Giannopulu, and Baudonniere (1995) reported that the time taken for vection to be induced (latency) could be shortened by informing participants that their seat was able to move according to the optic flow. Palmisano and Chan (2004) manipulated the effect of biasing participants toward the perception of self-motion or object motion by providing different types of information prior to the experiment. The results revealed that objectmotion-biased participants experienced weaker vection than did self-motion-biased participants (Palmisano & Chan, 2004).…”

Illusory Upward Self-Motion Results in a Decrease in Perceived Room Temperature

“…It is known that vection can be modulated by an experimenter's instructions or demands (Palmisano & Chan, 2004). Thus, we carefully instructed the participants regarding their task without giving them any suggestion which may lead to a cognitive bias about the consistency hypothesis.…”