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Souta Hidaka, Masayoshi Nagai, Jiro Gyoba; Non-reversed motion perception induced by the spatiotemporal reversal of apparent motion sequences. Journal of Vision 2008;8(6):601. doi: 10.1167/8.6.601.
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© ARVO (1962-2015); The Authors (2016-present)
Apparent motion between two or more stimuli cannot be perceived until the next stimulus is presented. This characteristic suggests that the representation of apparently moving objects is interpolated after the presentation of the subsequent stimulus. In order to investigate whether or not representation is capable of affecting physical spatiotemporal properties, we investigated apparent motion perception in a situation involving the spatiotemporal reversal of motion sequences. Our apparent motion display comprised five stimuli (0.4 × 0.8 deg each) horizontally aligned with a gap of 0.4 deg. The stimuli were presented sequentially. The durations and interstimulus intervals (ISIs) were 13.33 ms (30 deg/s). Our participants reported the motion direction of the last two stimuli (the test sequence). We discovered that, even when the spatiotemporal orders of the test sequence were reversed, the motion direction perception of the test sequence was consistent with the three stimuli (the prior sequence) presented first. This “misperception” did not occur in the absence of the prior sequence. We replicated these findings when the fourth stimulus contained a vertical offset. Further, we confirmed that the prior sequence comprising only one stimulus (three-point apparent motion display) was sufficient to produce the misperception of the test sequence; this effect reached a ceiling when the prior sequence contained two or more stimuli. Moreover, the perceived motion direction of the test sequence could not be altered by the apparent motion sequence of nearby objects. These findings suggest that the internal representation constructed after the presentation of all the stimuli would make the spatiotemporal reversal of motion sequences unaware. Moreover, it was revealed that the perceived speed of motion with the test sequence reversal was faster than that without the reversal. This suggests that, different from motion direction perception, velocity perception could be rather affected by the reversal.
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