John E. Drury, SUNY Stony Brook: Left anterior negativities (LANs) in language ERP research

ABSTRACT: For a brief period near the end of the 20^th century, it seemed possible to distinguish between “syntactic” and “semantic” aspects of human language processing by looking at qualitative differences in patterns of voltage change extracted from scalp-recorded electrical brain activity (i.e., event-related brain potentials or ERPs). It had been found that encounters with syntactic deviance (e.g., He criticized Max’s *of proof the theorem) elicit early (100-250 ms) and/or slightly later (300-500 ms) negative-going shifts over left/anterior regions of the scalp (so-called “E/LANs”; Neville et al. 1991; Friederici et al. 1993), typically followed by positive shifts (600-900 ms) over posterior (parietal) scalp regions, known as P600 effects (Osterhout & Holcomb 1992; Hagoort et al. 1993). In contrast, lexical-conceptual anomalies (e.g., John ate *democracy) were already known to elicit a broad negative-going shift, usually with a central/parietal maximum, peaking around 400 ms (N400 effects; Kutas and Hillyard 1980). Such findings led to the suggested correspondence between “syntax” and the biphasic (E)LAN-P600 pattern, and between “semantics” and the N400. However, subsequent research has made it clear that any simple 1-to-1 mapping of the syntax/semantics distinction to these ERP profiles is unsustainable and, moreover, that such effects are not specific to language. One way of thinking about the etiology of these effects makes reference to broad and plausibly domain-general distinctions between types of memory systems and/or cognitive operations (e.g., unification, integration, access/retrieval). In this talk I’ll discuss some ongoing efforts which aim to advance our understanding of how the kinds of general cognitive mechanisms different ERP signatures may index could be seen to play similar roles across different sub-domains human language in the temporal dynamics of comprehension. The primary focus of this talk, however, will be on “LAN-type” effects. In addition to the (E)LAN seen for syntactic violations, research has uncovered a number of superficially similar effects which vary as a function of the type of stimulus contrast and (for some effects) upon individual/group differences (e.g., working memory). I’ll discuss some ways of thinking about how the broader family of such effects may be related, presenting some new data along the way and summarizing some points from a recent critical review of the ELAN literature (Steinhauer & Drury, in press).