Speaker: Yosef Grodzinsky — McGill University
Date/Time: Friday 3/9 3:30 pm
Location: 32-141
Title: The Analysis of Negative Quantifiers: Multi-modal Evidence
Abstract:
Recent discussion of negative quantifiers (see Penka, 2011 and references therein) focuses on two main questions: do these quantifiers decompose, and if so, what are the mechanisms for decomposition? In this talk, I will describe a series of neuro- and psycholinguistic experiments my colleagues and I have conducted with healthy and brain-damaged participants that aim to provide relevant evidence. These experiments recorded responses from several modalities, as participants were analyzing sentences with positive and negative proportional and degree quantifiers in German and English (e.g., mehr/weniger-als-die-Hälfte die Kreise sind Gelb, many/few of the circles are blue).
All experiments used a Parametric Proportion Paradigm (PPP): participants were exposed to sentence-scenario pairs, and were requested to make truth value judgments. Sentences contained a quantifier in subject position, and scenarios depicted a proportion between 2 types of objects. Proportion was a parameter, systematically varied across images that were presented with each sentence type.
Our first experiment used functional MR imaging to extract a signal that represents localized brain activity. It aimed to identify brain loci that evince an intensity differential between the contrasting stimuli. Signal intensity for sentences with negative quantifiers was higher than that for their positive counterparts only in Broca’s region. Importantly, no other localizable intensity contrasts were found.
A second experiment (currently only a pilot) confronted English speaking, focally brain damaged, Broca’s aphasic patients with the same task. However here, the dependent measure was error rate. The results suggest a remarkably selective deficit: While patients performed near-normally on the positive quantifiers, their scores were drastically reduced when the stimuli contained negative quantifiers.
A third experiment attempted to take a deeper look at the behavioral signature of quantifier analysis through a study of complex RT functions obtained from healthy participants. Here, too, we observed that the signature of negative quantifiers is quite distinct from that of their positive counterparts.
In this talk, I will try to connect these results, obtained through different modalities from different populations, to previous ones that come from parametric studies of overt syntactic movement with healthy participants in fMRI, and with Broca’s aphasic patients. I will propose that a generalization over the experimental results supports an analysis of sentences with negative quantifiers that assumes covert movement. I will then try to situate these results in the broader context of a research agenda that tries to create a brain map of syntactic and semantic knowledge.