One of the most remarkable functional feats accomplished by visual system is the interpolation of missing retinal inputs based on surrounding information, a process known as perceptual completion. Perceptual completion enables the active construction of coherent, vivid percepts from spatially discontinuous visual information that is prevalent in real-life visual scenes. Despite mounting evidence linking sensory activity enhancement and perceptual completion, surprisingly little is known about whether and how attention, a fundamental modulator of sensory activities, affects perceptual completion. Using EEG-based time-resolved inverted encoding model (IEM), we reconstructed the moment-to-moment representation of the illusory grating that resulted from spatially interpolating the orientation of surrounding inducers. We found that, despite manipulation of observers' attentional focus, the illusory grating representation unfolded in time in a similar manner. Critically, attention to the surrounding inducers simultaneously attenuated the illusory grating representation and delayed its temporal development. Our findings disclosed, for the first time, the suppressive role of selective attention in perceptual completion and were suggestive of a fast, automatic neural machinery that implements the interpolation of missing visual information.

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Many studies have found that the orthographic neighborhood frequency (NF) effect plays a dominant role in word identification. Yet most research has been conducted on alphabetic languages rather than Chinese. We investigated the NF effect on Chinese character recognition in the context of lexical decision tasks. Experiment 1 tested the NF effect in simple characters, Experiment 2 tested the NF effect in compound characters. Results showed that targets with higher frequency neighbors had longer response latencies for both simple characters and compound characters, and that this inhibitory effect was more significant for low-frequency targets. The results overall imply there is an inhibitory NF effect existing in Chinese character recognition. The implications of the results are discussed with regard to character recognition.

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