The recognition potential and rotated Chinese characters

The recognition potential (RP), which is recorded at occipital-temporal sites 200-300 ms poststimulus onset, is an event-related potential (ERP) response to a recognizable stimulus during an object recognition task. Using the rapid stream stimulation (RSS) paradigm and a word detection task, the present study investigated the effect of word detection on RP activity by manipulating angular orientation and image version of Chinese characters. The results showed larger RP amplitude during the normal condition than during the mirror-reversed condition across angular orientations. Moreover, the RP latencies were delayed for 60°, 120°, and 180° orientations relative to the upright, and the amplitudes were larger for 0° and 60° orientations than for 120° and 180° orientations only during the normal condition. This suggests that, as mirrored by RP activity, different strategies depend on the difficulty of word recognition. More specially, piecemeal and serial processing strategy would be used when incoming information is sufficient for word recognition, whereas holistic strategy and the global analysis of categorical features would be used when a word cannot be recognized due to the degraded quality of incoming stimuli.