Two different types of morphological structure of a Chinese disyllable word can be readily identified based upon the relationship between the overall word meaning and the meaning of its constituent syllables/morphemes. At one end, there are idiomatic compound, like 和尚 ('monk'), in which the meaning of the word has nothing to do with the meaning of the constituent elements. On the other hand, there are compositional compounds, such as 書店 ('bookstore'), in which the meaning of the word can be computed from the meanings of the constituent elements. Results from previous psycholinguistic experiments, which attempted to specify the processes of word recognition, had provided evidence for a direct look-up procedure, in addition to the default constructive procedure. It was found that increasing the degree of idiomaticity reduced the effect of character frequency of the constituent elements whereas the effect of word frequency was immune to the same manipulation.
Previous literature has established that while automatic activation of associative meaning can occur in both hemispheres, only the left hemisphere engages in controlled process of constructing meaning from local constituents In contrast, results from clinical observations have pointed out that difficulty in processing idioms is associated with the right hemisphere damage. These results have direct implications for the processing for the two types of the two types of Chinese disyllable compounds with regards to their neurolinguistic pathways.
Right and left brain damaged Chinese patients were asked to perform a lexical decision task in which a two-character word is presented on the center of the computer monitor and they were to judge whether the stimulus characters together formed a meaningful Chinese word. They indicated their decision by pressing a YES or NO button with their functional fingers. Both response times (RTs) and accuracy of the decision were recorded by the computer. Results of the patients were compared to those of normal controls. The dissociation between the direct look-up process and the controlled process of construction was confirmed. More importantly, the data also suggest that the right-hemisphere lexicon may be more richly endowed than earlier thought.