We are currently working on a few projects. We are investigating how phonology influences letter identification when letters are embedded in real words, pseudowords (e.g., lape), and nonwords (e.g., lcvx). We are also investigating how letters are grouped together when we are presented with a string of letters (are adjacent letters processed together? are non-adjacent letters?). Furthermore, we are starting a new project aimed at investigating changes in visual word recognition systems driven by learning a second language (L2). This is an extension of work recently done in collaboration with Guillaume Thierry at the ESRC Centre for Research on Bilingualism at Bangor University, Wales.
In a recent paper (Grossi, Savill, Thomas, & Thierry, 2010), we studied the N1, a negative component elic
ited by words and other linguistic stimuli over the parieto-occipital site between 130 and 200 ms. The N1 has been found to be larger over the left (e.g., PO7) than the right (e.g., PO8) posterior sites in expert readers. [see picture on the right: y axis = microV; x axis = ms; negative is plotted up; the N1 peaks at 150 ms]
In late bilinguals (individuals who learned a second language after puberty), the N1 became more left-lateralized for Welsh (L2) with increasing experience in the second language in late bilinguals. That is, the longer the experience with Welsh, the more asymmetric (left > right) the N1 was over the posterior sites.
This developmental pattern has also been observed in children learning to read (the N1 becomes left-lateralized with increasing expertise). Therefore, our data suggest that the organization of visual areas involved in word recognition is driven by experience with a language, not by age of acquisition, and that the degree of plasticity of these areas remains considerable in spite of the presence, in adult late bilinguals, of circuits already tuned to the first language.
The new study, on English-Spanish bilinguals, will investigate whether learning a second language impacts the organization of brain systems associated with the first language, and how words in the first and the second language are integrated.