Doctoral Dissertation Research: Linguistic illusions and incremental interpretation

Adults are very good at understanding sentences quickly and easily. Psycholinguists often use their occasional mistakes as a way to understand the mechanisms that underlie this speed and ease. This project investigates two varieties of language comprehension errors, which reveal the underlying computations that allow language users to understand most sentences so successfully.

The first of these errors involves the failure to notice anomalous word substitutions. For example, when asked "what is the name of the holiday during which children dress up and go door to door giving candy?", many people do not notice the substitution of "giving" for "receiving" and simply answer "Halloween". The failure to detect this type of word substitution can be thought of as a type of illusion - the comprehender imagines the sentence to be different from how it actually is.

This project investigates what causes these illusions - for example, whether "giving" was simply mis-read, or if the meaning of the word was mis-remembered, or if attention was mis-directed toward other parts of the sentence. Identifying the processing mis-step that causes this particular error provides clues as to where comprehenders are vulnerable to misunderstanding more generally.

The second case study concerns the processing of a special class of words known as negative polarity items or NPIs. These are words like "ever" and "any", which are generally appropriate in negative contexts (e.g. "John doesn’t have any money.") but sound strange or ungrammatical in positive contexts (e.g. "John has any money."). Prior work has shown that an NPI in a positive context can seem, at first glance, to be appropriate if there is a negative context nearby, another type of linguistic illusion.

This project investigates the specific circumstances under which this mistaken perception arises, in addition to asking what people think these ungrammatical sentences actually mean when they judge them to be grammatical.

This project uses a combination of speeded and unspeeded judgments, eye-tracking methods, and sentence repetition tasks to measure people’s responses to illusion sentences. Two initial experiments on word substitution illusions test how often mistakes occur when the substitution is in a declarative sentence instead of a question, and when the substituted word has been primed through previous exposure.

Two independent experiments investigate the role of attention by measuring eye movements as comprehenders read sentences with various types of anomalies, including both word substitutions and spelling errors. Three additional experiments on NPI illusions investigate the causes and consequences of these errors. First, two experiments using speeded acceptability measures test the influence of broader conversational context and expectations on illusion rates, and the role of the precise timing of the appearance of the NPI.

Finally, a sentence repetition experiment, in which subjects attempt to recall an NPI illusion sentence after a delay, reveals the inferred meaning of these sentences.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.