A specific and central focus is on understanding the processes underlying the learning of new words. Understanding the cognitive processes that underlie this ability is of great significance, but surprisingly little is known about it. In studying how words are learned, it is relevant to consider how nonwords (such as "blork") are processed, because when a human learner first encounters a novel word, it is in effect a nonword to that person. So understanding how people are able to repeat a nonword immediately upon hearing it for the first time (nonword repetition) is relevant to understanding how they eventually learn new words. Another relevant human facility is verbal short-term memory -- memory for sequences of words, as, for example, when we temporarily keep in mind the digits of an unfamiliar phone number until it can be dialed. A growing body of evidence indicates that human vocabulary learning, nonword repetition, and verbal short-term memory abilities are related in some way (e.g., Baddeley, Gathercole, & Papagno, 1998; Gathercole & Baddeley, 1993). Research in our lab aims to uncover the details of processing mechanisms that could underlie these various abilities (e.g., Gupta & MacWhinney, 1993, 1995; Gupta, 1996a, 1996b; Gupta & MacWhinney, 1997; Gupta, Lipinski, Abbs, & Lin, 2005), and has also attempted to specify the neural correlates of these processes and relationships (e.g., Gupta & MacWhinney, 1997; Gupta, MacWhinney, Feldman, & Sacco, 2003; Martin & Gupta, 2004). In addition, based on computational considerations as well as neuropsychological evidence, we have proposed that the process of learning a single new word can be fractionated into components that rely differentially on the two long-term memory systems termed procedural memory and declarative memory (Gupta & Dell, 1999; Gupta & Cohen, 2002; Gupta & Lipinski, 2002). These various lines of research in our lab together lead to a view of how verbal short-term memory, linguistic processes and representations, and procedural and declarative memory systems are jointly invoked in order to learn new lexical items, and this serves as our general theoretical framework.
Various projects are aimed at testing and fleshing out this framework. One project asks whether the correlations observed between verbal short-term memory, nonword repetition, and vocabulary learning in children also persist in adults. In a series of experiments, we have provided new evidence that this is the case (Gupta, 2003). We have also investigated the bases of such relationships, finding evidence that the serial position effects widely observed in list recall are also obtained for syllables within multi-syllable nonwords suggesting that common sequencing mechanisms are implicated in list recall and in nonword repetition (Gupta, 2005; Gupta, Lipinski, Abbs, & Lin, 2005). In another project, we have developed a new experimental paradigm for the investigation of the learning of new words, which allows us to systematically examine factors affecting word learning (Gupta, Lipinski, Abbs, Lin, Aktunc, Ludden, Martin, & Newman, 2004. In other research we are exploring differences in semantic vs. phonological processing in word learning, based on theoretical and computational arguments (e.g., Gupta & Dell, 1999) that predict processing differences in these two aspects of lexical learning. In other ongoing work, our computational model of vocabulary acquisition and its relationship to lexical processing (e.g., Gupta, 1996b), is being revised. An important goal of this research is to develop a computational model integrating our earlier work with that of our collaborators at the Beckman Institute (Gary Dell) and Temple University (Nadine Martin), and to apply the integrated model to investigating language and verbal short-term memory deficits in aphasic patients, whose language abilities have been impaired following brain injury (e.g., Martin, Saffran, Dell, Schwartz, & Gupta, 2000; Martin & Gupta, 2004). Other issues studied in our lab include human statistical learning of syntactic structure in language (e.g., Ludden & Gupta, 2000) and the effects of neighbohood structure on the processing and learning of nonwords (Lipinski & Gupta, 2003; Lambert, Chang, & Gupta, 2003; Lipinski & Gupta, 2005).
An important characteristic of research in our lab is the use of
interdisciplinary approaches and multiple methodologies. Thus, we study issues
from the perspectives of language processing, memory systems, and cognitive
neuroscience, using experimental methods, computational models, and
neuropsychological/neuroscientific techniques. It is our belief that the use
of converging operations of this kind holds great promise for the elucidation
of the issues we are studying.
Lab control room
A typical lab meeting
David Ludden presents research at a conference
Running a computer simulation
Example "alien" used in word learning experiments
Software used to configure experiments
