Abstract
The attentional blink (AB) refers to a robust attentional phenomenon that in a rapid serial visual presentation, the detection of T1 leads to a deficit for T2 within a brief period. However, the present studies of AB have rarely addressed the question of exactly what spatial or form attribute of targets and distractors determines the presence and extent of the AB. This may reflect a lack of theoretical framework for understanding the fundamental question in any theory of attention: what attribute of a stimulus defines a perceptual unit that attention selects. We proposed, inspired by the “global-first” topological definition of perceptual unit, a topological hypothesis that topological change (TC) between the targets and distractors presented in a rapid sequence may be perceived as an emergence of new perceptual unit, thus triggers the AB. This hypothesis was tested in 7 experiments. Letters, digits and geometric forms, were used as T1 (e.g. E vs. P), T2 (e.g. H) and distractors (e.g., S/U) for representing TC in holes between them (e.g., P vs. S/U), and meanwhile to control for non-topological factors, including line-segment, shape, color, and semantic elements. The results consistently showed that the TC in holes from distractors to T1 triggered AB, while no AB was observed when T1 and distractors were topologically equivalent. Furthermore, to explain why AB occurred in the previous studies, which didn't specifically manipulated topological property, we replicated the findings by Raymond, Shapiro, & Arnell (1992) and Chun & Potter (1995), and found that in 85% of the trials, there was TC between T1 and distractors located within the range of −3 to +1 lags. In summary, all results consistently supported our topological hypothesis for the AB in particular, and that a peceptual unit can be defined as something that keeps its topological structure over time in general.
This work was supported by Grants 2005CB522801 and 2009IM030900 from the Ministry of Science and Technology of China, Grants 30621004 and 90820307 from the National Nature Science Foundation of China, Grants KSCX2-YW-R-122 and KSCX2-YW-R-259 from the Chinese Academy of Sciences, and by the Knowledge Innovation Projects of the Chinese Academy of Sciences.