There is broad consensus that the visual word recognition system is sensitive to morphological structure (e.g., “hunter” = “hunt” + “er”). Moreover, it has been assumed that the analysis of morphologically complex words (e.g., “hunter”) occurs only if the meaning of the complex form can be derived from the meanings of its constituents (e.g., “hunt” and “er”). However, recent behavioral work using masked priming has suggested that morphological analysis can occur at an early, orthographic level, with little influence from semantics. The present investigation examined the neurophysiological correlates of masked priming in conditions of a genuine morphological relationship (e.g., “hunter”-“HUNT”), an apparent morphological relationship (“corner”-“CORN”), and no morphological relationship (“brothel”-“BROTH”). Neural priming was indexed by the reduction of the N400 ERP component associated with targets preceded by related primes, as compared to targets preceded by unrelated primes. The mere appearance of morphological structure (“corner”-“CORN”) resulted in robust behavioral and neural priming, whose magnitude was similar to that observed in pairs with genuine morphological relationship and greater than that in the nonmorphological pairs. The results support a purely structural morphemic segmentation procedure operating in the early stages of visual word perception.

To examine the role of meaning in morphological decomposition ({re-}+{play}) researchers have employed the priming paradigm. Perceptually masked primes lead to facilitation both when decomposition is semantically appropriate (hunter-HUNT) and when it is not (corner-CORN), whereas with fully-visible primes facilitation is observed only in the former case. We investigated the N400 brain potential time-locked to words preceded by fully-visible primes. At ~300-380ms, N400 was equally attenuated in the semantically 'transparent' condition (hunter-HUNT) and semantically 'opaque' condition (corner-CORN). In the transparent condition, N400 remained attenuated after 380 ms, whereas in the opaque condition it returned to the level of a non-morphological form condition (brothel-BROTH). This pattern of N400 priming is consistent with an orthography-based, morphological decomposition mechanism, 'licensed' at a later stage by semantic information.

A key index of top-down control in task switching-preparation for a switch-is underexplored in language switching. The well-documented EEG "signature" of preparation for a task switch-a protracted positive-polarity modulation over the posterior scalp-has thus far not been reported in language switching, and the interpretation of previously reported effects of preparation on language switching performance is complicated by confounding factors. In an experiment using event-related potentials (ERPs) and an optimized picture-naming paradigm that addressed these confounds the language was specified by an auditory cue on every trial and changed unpredictably. There were two key manipulations. First, the cue-stimulus interval allowed either generous (1,500 ms) or little (100 ms) opportunity for preparation. Second, to explore the interplay between bottom-up and top-down language selection, we compared a highly transparent and familiar "supercue"-the name of the language spoken in that language to a relatively opaque cue (short speeded-up fragment of national anthem). Preparation for a switch elicited a brain potential strongly reminiscent of the posterior switch positivity documented in task switching. As previously shown in task switching, its amplitude inversely predicted the performance "switch cost," demonstrated by our ERP analyses contingent on reaction time (RT). This overlap in the electrophysiological correlates of preparing to switch tasks and languages suggests domain-general processes for top-down selection of task-set and language for production. But, the surprisingly small language switch cost following the supercue in the short CSI suggests that rapid and (possibly automatic) bottom-up selection-not typically observed in task switching-may also occur. (PsycINFO Database Record

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