Кеңістіктік қабылдау иллюзиясы: Тау эффектісі

Spatial perceptual illusion
The tau effect is a spatial perceptual illusion that arises when observers judge the distance between consecutive stimuli in a stimulus sequence. When the distance from one stimulus to the next is constant, and the time elapsed from one stimulus to the next is also constant, subjects tend to judge the distances, correctly, as equal. However, if the distance from one stimulus to the next is constant, but the time elapsed from one stimulus to the next is not constant, then subjects tend to misperceive the interval that has the shorter temporal interval as also having a shorter spatial interval. Thus, the tau effect reveals that stimulus timing affects the perception of stimulus spacing. Time is also a perceived quantity and subject to its own illusions; research indicates that in the tau effect, perceived stimulus spacing follows perceived (phenomenal) time rather than actual (physical) time.

The tau effect can occur with visual, auditory, or tactile stimuli. It was later given its name by Helson (1930) and characterized in detail by Helson and King (1931). showed that the time intervals between auditory tones could affect subjects' perceptual judgements of the spatial interval between visual flashes in a manner consistent with that predicted by the tau effect.

Physically, traversed space and elapsed time are linked by velocity. It is logical, then, to consider that the tau effect occurs as a consequence of the brain's assumption regarding stimulus velocity. Indeed, different theories regarding the brain's expectations about stimulus velocity have been put forward in an effort to explain the tau effect.

According to the constant velocity hypothesis proposed by Jones and Huang (1982), perception incorporates a prior expectation for constant speed. Therefore, given the temporal intervals marked by sequential stimuli, the brain expects spatial intervals that would yield constant velocity movement (i. e., uniform motion). is that it does not explain why even two stimuli pressed in rapid succession against the skin are perceived as closer together the shorter the temporal interval between them is. In the absence of a third stimulus that creates a second spatial and temporal interval, the constant velocity hypothesis can have no bearing on this two stimulus situation.