Syntax, concepts, and logic in the temporal dynamics of language comprehension: evidence from event-related potentials

Abstract

Logic has been intertwined with the study of language and meaning since antiquity, and such connections persist in present day research in linguistic theory (formal semantics) and cognitive psychology (e.g., studies of human reasoning). However, few studies in cognitive neuroscience have addressed logical dimensions of sentence-level language processing, and none have directly compared these aspects of processing with syntax and lexical/conceptual-semantics. We used ERPs to examine a violation paradigm involving "Negative Polarity Items" or NPIs (e.g., ever/any), which are sensitive to logical/truth-conditional properties of the environments in which they occur (e.g., presence/absence of negation in: John hasn't ever been to Paris, versus: John has *ever been to Paris). Previous studies examining similar types of contrasts found a mix of effects on familiar ERP components (e.g., LAN, N400, P600). We argue that their experimental designs and/or analyses were incapable of separating which effects are connected to NPI-licensing violations proper. Our design enabled statistical analyses teasing apart genuine violation effects from independent effects tied solely to lexical/contextual factors. Here unlicensed NPIs elicited a late P600 followed in onset by a late left anterior negativity (or "L-LAN"), an ERP profile which has also appeared elsewhere in studies targeting logical semantics. Crucially, qualitatively distinct ERP-profiles emerged for syntactic and conceptual semantic violations which we also tested here. We discuss how these findings may be linked to previous findings in the ERP literature. Apart from methodological recommendations, we suggest that the study of logical semantics may aid advancing our understanding of the underlying neurocognitive etiology of ERP components.

Figure 1. Monotonicity and NPI-licensing properties of EVERY, SOME, and NO

We assume here a view of quantifiers as predicates of sets (see Barwise & Cooper 1981). On this view a quantifier Q takes two arguments, its “A”-argument or restriction and its “B”-argument (here: the main predicate). Thus, for example, in Every boy arrived, every is the quantifier, its restriction (A-argument) is the associated noun (boy), and the predicate arrived is “B-argument”. Satisfying the truth conditions for EVERY(A, B) would involve checking to see whether the set of entities that are boys is a subset of the set of entities that arrived (formally: EVERY(A, B) is true iff A ⊆ B). These three different quantifiers manifest different patterns of upward and downward monotonicity over each of their two arguments (illustrated by the upward and downward arrows connecting the example sentences in the left-hand panel above). Every, for example, is downward monotonic over its “A”-argument and upward monotonic over its “B”-argument (we mark this as EVERY(A⁻, B⁺), with the “−/+” marking downward/upward monotonicity, respectively), and this is evident both in the entailment patterns and in the distribution of NPIs (compare left and right panels above). In contrast, some is uniformly upward monotonic and cannot license an NPI in either position, and no is uniformly downward monotonic and uniformly licenses NPIs.

Figure 2

Regions of Interest and Midline Electrodes Used in Analysis (note that electrodes marked in black appear in the grand average plots below (Figures 4–5).

Figure 3

End of sentence acceptability judgment performance (mean % of acceptance by condition; labels for filler conditions (1)a–c and the critical NPI-licensing conditions (2)a–d correspond to those in Table 1).

Figure 4

Grand average waves for (A) NPIs (critical) and (B) non-NPIs (control) in Licensing versus Non-Licensing Contexts.

Figure 5

Grand average waves for (A) Phrase-structure and (B) Conceptual semantic violations.

Figure 6

The P600/L-LAN pattern for the three individual NPIs we tested (ever, any, at all) for midline parietal (Pz) and left anterior (FC7) electrodes showing representative effects. Note that at all also showed an N400 modulation which was absent for any and ever.

Figure 7

A (left) anterior negativity for non-NPIs relative to NPIs (averaging over Licensing/Non-Licensing – i.e., a main effect of word-type).