Abstract
We investigate here the implicit encoding of a temporal sequence of visual events and the expectation to complete the sequence. For this purpose, we tested the extent to which a series of non-rivalrous patterns can influence the dominant perception in binocular rivalry. We rely on and extend the pattern suppression phenomenon: when rivalrous oriented Gabors follow non-rivalrous Gabors, observers usually perceive the repeated orientation less often (Brascamp, Knapen, Kanai, van Ee & van den Berg, 2007). Our observers viewed sequences of non-rivalrous Gabors that could be oriented either to the left (A) or to the right (B). Sequences varied in length up to four items, for instance AABA. A pair of rivalrous Gabors then followed the sequence where A was presented to one eye and B to the other. The spatial frequency of the images during this rivalry presentation was slightly different from that of the images during the sequence and observers reported their dominant percept by referring to its spatial frequency (higher or lower than the sequence). We found that the dominant percept during the rivalrous stage was largely predictable from the previous sequence of non-rivalrous patterns. The primary factor was related to adaptation: the more often A was presented during the sequence, the more likely B would be perceived during rivalry. Another factor was related to alternation: after the sequence BABA, B was more likely to be perceived than after the sequence AABA. These results are consistent with the phenomenon of pattern completion found with the ambiguous motion quartet (Maloney, Dal Martello, Sahm & Spillmann, 2005). In conclusion, binocular rivalry is not only influenced by adaptation of a pattern seen in the past, but also by more complex temporal structures such as the one found in the alternation of two patterns within a sequence.