Bilateral redundancy gain (BRG) indicates superior performance in bilaterally presented word recognition in the left and right visual fields (RVFs) relative to word recognition given in either the left or the RVF. The BRG may be modulated by participants’ subjective familiarity with words as previous studies found smaller regional activations in the brain as they become proficient. It can be assumed that visual recognition of words with high subjective familiarity indicates skilled performance in visual recognition. Thus, this study examined the subjective familiarity effect of visual words on the BRG during lateralized lexical decision performances. It showed that the significant BRG of response times was only observed in the most familiar word condition (F4 level); on the other hand, accuracy results revealed the significant BRGs in all the subjective familiarity levels (F1, F2, F3, and F4 levels). These results suggest that the bilateral presentation of identical words with higher subjective familiarity facilitates the recognition led by cooperative interactions between cerebral hemispheres. Therefore, the subjective familiarity with visual words modulates the efficiency of hemispheric interactions in visual word recognition.

Greater word length effects have been reported when a word was presented in the left visual field (LVF) than when presented in the right visual field (RVF). The current study employed 2 experiments to examine the visual-perceptual loci of asymmetric word length effect while testing the physical and linguistic length effects and the effect of visual angle increase at the RVF. Experiment 1 showed significant effects on the number of strokes in both VHFs (visual half fields) with the added significance of the number of syllables in the LVF, suggesting both parafoveal fields were affected by the physical length factors in contrast with the linguistic length factors, inducing asymmetric word length effects in the symmetrically presented word recognition in parafoveal vision. Experiment 2 widened the visual angle of the RVF presentation to test the differential effects of the visual-perceptual difficulty across the VHFs. It showed successful interruption at the RVF word recognition and comparable word length effects between the LVF and RVF. Therefore, this study suggests that the asymmetric word length effects in the parafoveal word recognition are attributable to the greater visual-perceptual difficulty at the LVF than at the RVF.

An intense debate in monolingual research concerns the presence of phonological recoding in word recognition. Research supporting the phonological recoding hypothesis in monolingual research suggests the possibility of phonological recoding even in L2 recognition. There has been some experimental evidence showing phonological priming between L1 and L2 for alphabetic bilinguals (e.g., French‐Dutch). In the present study, lexical decision experiments used either L1 or L2 primes with targets from the other language at SOAs of 140 ms and 250 ms for Korean‐English bilinguals. It was found that phonological information activated by either an L1 or L2 prime can interact with phonological information in the other language. That is, L2 shares phonological information with L1, and its spelling–sound knowledge is activated, apparently automatically, at an SOA of 140 ms. The consistent pattern of phonological priming of both L1 and L2 targets at the 140 ms SOA indicates that the spelling–sound knowledge of bilingual lexicons is activated when any linguistic form is presented. Importantly, this indiscriminate activation of spelling–sound knowledge in the Korean‐English bilingual system occurs in the absence of any common orthographic cues because the two languages have totally different writing systems.

When people confuse and reject a non-word that is created by switching two adjacent letters from an actual word, is called the transposition confusability effect (TCE). The TCE is known to occur at the very early stages of visual word recognition with such unit exchange as letters or syllables, but little is known about the brain mechanisms of TCE. In this study, we examined the neural correlates of TCE and the effect of a morpheme boundary placement on TCE. We manipulated the placement of a morpheme boundary by exchanging places of two syllables embedded in Korean morphologically complex words made up of lexical morpheme and grammatical morpheme. In the two experimental conditions, the transposition syllable within-boundary condition (TSW) involved exchanging two syllables within the same morpheme, whereas the across-boundary condition (TSA) involved the exchange of syllables across the stem and grammatical morpheme boundary. During fMRI, participants performed the lexical decision task. Behavioral results revealed that the TCE was found in TSW condition, and the morpheme boundary, which is manipulated in TSA, modulated the TCE. In the fMRI results, TCE induced activation in the left inferior parietal lobe (IPL) and intraparietal sulcus (IPS). The IPS activation was specific to a TCE and its strength of activation was associated with task performance. Furthermore, two functional networks were involved in the TCE: the central executive network and the dorsal attention network. Morpheme boundary modulation suppressed the TCE by recruiting the prefrontal and temporal regions, which are the key regions involved in semantic processing. Our findings propose the role of the dorsal visual pathway in syllable position processing and that its interaction with other higher cognitive systems is modulated by the morphological boundary in the early phases of visual word recognition.