Advantage of the go/no-go task over the yes/no lexical decision task: ERP indexes of parameters in the diffusion model.

Previous research findings supporting the advantages of the go/no-go choice over the yes/no choice in lexical decision task (LDT) have suggested that the go/no-go choice might require less cognitive resources in the non-decisional processes. This study aims to test such an idea using the event-related potential method. In this study, the tasks (yes/no LDT and go/no-go LDT) and word frequency (high and low) were manipulated, and the difference between the go/no-go choice and yes/no choice were examined with BP, pN, pN1, P200, N400, and P3 components that were assumed to be closely related with the various parameters in the diffusion model. The results showed that BP, pN and pN1 amplitudes reflecting the preparation stage were not differently affected by word frequency and the task type. However, ERPs after stimulus onset showed differences. The P200 amplitudes were smaller in the go/no-go task than in the yes/no task only for low-frequency words. N400 and P3 amplitudes were only affected by word frequency. The results suggest that the go/no-go task and the yes/no task differ in sub-lexical processes, which is indicated in the Tencoding parameter in the diffusion model. This study is important as it offers the first electrophysiological evidence supporting the assumption in the diffusion model that explains the advantage of the go/no-go choice over the yes/no choice.

Early Effect of Phonological Information in Korean Visual Word Recognition: An ERP Investigation with Transposed Letters.

The purpose of this study was to examine the role of phonological information on visual word recognition by using letter transposition effects. The Korean writing system gives a unique opportunity to investigate such phenomenon since the transposition of the beginning consonant (onset) and the end consonant (coda) of a certain syllable allows one to keep the coda phonology constant while changing the written alphabetic characters. In this study, 23 participants' ERPs to such transposition cases were compared with the ERPs to cases that do not maintain coda phonology while the participants were performing a go/no-go lexical decision task for visually presented letter strings. The results of the current study showed that transposed materials with original phonological information produce less N250 than both the baseline condition and the transposed materials with different phonological information condition. The results suggest that phonological information is used early in the lexical process in Korean and early orthographic processing is influenced by the characteristics of the grapheme to phoneme conversion process.

Early use of orthographic information in spoken word recognition: Event-related potential evidence from the Korean language.

This study examines whether orthographic information is used during prelexical processes in spoken word recognition by investigating ERPs during spoken word processing for Korean words. Differential effects due to orthographic syllable neighborhood size and sound-to-spelling consistency on P200 and N320 were evaluated by recording ERPs from 42 participants during a lexical decision task. The results indicate that P200 was smaller for words whose orthographic syllable neighbors are large in number rather than those that are small. In addition, a word with a large orthographic syllable neighborhood elicited a smaller N320 effect than a word with a small orthographic syllable neighborhood only when the word had inconsistent sound-to-spelling mapping. The results provide support for the assumption that orthographic information is used early during the prelexical spoken word recognition process.

The role of orthographic syllable frequency in the syllable frequency effect: evidence from Korean.

There have been ongoing debates as to whether the syllable frequency effect is dependent purely on phonological representation or is also affected by the orthographic representation of the syllable. In two experiments, the authors investigated the effect of the phonologic and orthographic frequencies on the syllable frequency effect by manipulating the first syllable's phonologic (high vs low) and orthographic (high vs low) frequency. Analyses of variance were performed for the lexical decision latencies and error rates in two experiments. Overall, the results of the current experiments showed effects of phonological syllable frequency on lexical decision latencies. Additionally, the results of the current experiments also showed the influence of the orthographic syllable frequency in the form of an interaction between the phonologic and orthographic frequencies. Longer latencies and higher error rates for higher phonological syllable frequency occurred only when the target word had low orthographic syllable frequency. The current study suggests that phonological syllable frequency is the primary sources of the syllable frequency effect while it also suggests that the orthographic representation of the syllable influences the syllable frequency effect as well.

Syllable transposition effects in korean word recognition.

Research on the impact of letter transpositions in visual word recognition has yielded important clues about the nature of orthographic representations. This study investigated the impact of syllable transpositions on the recognition of Korean multisyllabic words. Results showed that rejection latencies in visual lexical decision for syllable-transposed Korean nonwords were delayed as compared with matched Korean nonwords without syllable transpositions. These findings bolster the case that the syllable provides an important functional unit in Korean word recognition, and suggest a degree of position invariance in syllable representations.

Thematic roles, markedness alignment and processing complexity.

Two experiments used eye-tracking during reading to investigate the role of the consistency of the relative markedness alignment of noun phrases (NPs) in the processing of complex sentences in Korean. To do so, the animacy of the first NP was varied in both experiments to manipulate the relative markedness of NPs. In addition, case markings of the second NP (nominative vs. accusative) were manipulated in the first experiment and the markings of the first NP (nominative vs. topic) were manipulated in the second experiment. Results revealed that the animacy manipulation and the nominative-topicality manipulation showed measurable influence on the participants' reading of the complex sentences. Also, the effect of the prominence misalignment caused by animacy seems to have a stronger effect on reading than the effect caused by the nominative-topicality manipulation. The experiments suggested that on-line processing of Korean complex sentences are affected by the consistency of the relative markedness alignment of NPs.

Understanding mechanisms in transitive inferences: an eye-tracking study in Korean reading.

The current experiment examined the mechanism of relational information processing by assessing transitive inferences in different syntactic structures. More specifically, the current experiment focused on whether the demands of conscious inference processing interact with the difficulty of syntactic processing. This research used the eye-tracking method to investigate online processing mechanisms in complex sentences with transitive inference. Overall sentence reading times, accuracy rates of comprehension questions, and the two eye-movement measures of gaze duration and re-reading times were examined in 32 participants. The results showed that inference processing demands affected overall reading times and accuracy rates, while syntactic processing demands did not have an effect on overall reading times or accuracy rates. The results of the eye-tracking measures showed that syntactic processing demands affected gaze duration, while the inference processing demand affected re-reading times. Apparently, the difficulty of inference processing was not affected by the surface form of a sentence. The results of this study suggested that basic processes of sentence interpretation share resources with other cognitive processes such as inference.

ERP index of the morphological family size effect during word recognition.

The purpose of this study was to examine whether the N400 is affected by the semantic richness of associated neighboring word members or by the density of the orthographic syllable neighborhood. Another purpose of this study was to investigate the source of the different LPC in respect to the semantic richness. To do so, the density of the syllable neighborhood and the size of the morphological family of a word were orthogonally manipulated. ERPs from 24 participants were collected during a go/no-go semantic categorization task. The results showed that the N400 effect was mainly influenced by the density of the syllable neighborhood rather than by the morphological family size. The results also showed that words with a larger morphological family size generate significantly larger LPC than words with a smaller morphological family size. The present study did not support the assumption that the main source of the N400 effect is the semantic richness of the associated neighbors. The present results suggest that the N400 is more sensitive to the density of the syllable neighborhood and LPC is sensitive to the density of the semantic neighborhood reflected by the morphological family size.

The different P200 effects of phonological and orthographic syllable frequency in visual word recognition in Korean.

The principal purpose of this study was to examine whether event-related potential (ERP) waveform amplitudes at around 200 ms are affected by first-syllable frequency. Another purpose of this study was to investigate whether the source of the amplitude at around 200 ms is phonological syllable frequency or orthographic syllable frequency. The phonological first-syllable frequency and the orthographic first-syllable frequency of Korean pseudo-words were manipulated, and ERPs were collected during a go/no-go lexical decision task. The results of this study showed that the P200 waveform is sensitive to the frequency of the first phonological syllable; specifically, pseudo-words with higher phonological first-syllable frequency produced a lower P200 amplitude than those with lower phonological first-syllable frequency. The orthographic syllable frequency did not affect the P200 waveform. The present result implies that there may be different routes by which phonological syllables and orthographic syllables are processed during the early stage of the visual word recognition process.