Spatiotemporal feature integration within discrete time windows provides evidence for discrete perception

Intuitively, consciousness seems to be a continuous stream of percepts. Here, contrary to intuition, we show evidence for discrete consciousness, occurring only at certain moments of time. We presented a Vernier followed by a sequence of flanking lines on either side, leading to the percept of two diverging motion streams. The Vernier offset is visible at the flanking lines even though the Vernier itself is invisible due to metaconstrast masking. If an additional offset is introduced to one of the flanking lines, the two offsets integrate (Otto et al., 2006). Here, we show that this feature integration is mandatory and lasts up to 450ms. Surprisingly, when the offset is presented at 330ms SOA it integrates with the central offset but not with a third offset presented at 490ms SOA, even though the latter two are much closer in space and time. This result suggests that only features that are presented in the same time window integrate, supporting the concept of discrete consciousness.