25 November 2012

Paul Smolensky gives colloq on Friday

Paul Smolensky will give the department colloquium on Friday, November 30, in Machmer E-37 at 3:30pm.

Title: Gradient Symbols in Linguistic Competence and Performance

Ubiquitous in the study of cognition is the need to reconcile discrete combinatorial structure (as in linguistic representations) with continuous or ‘gradient’ structure. For example, this arises in psycholinguistics both empirically — in relating grammar to observables — and theoretically — as in partial ‘activation’ of competing alternatives. This reconciliation is also required for reducing discrete combinatorial grammatical computation to neural computation over continuous activation patterns. A general approach to this integration is Gradient Symbolic Computation, in which representations are combinatorial but consist in weighted blends of symbolic constituents. I will introduce a general cognitive architecture based on optimization, in which markedness, faithfulness and correspondence relations play central roles within and between all cognitive components. Of primary concern are computations in which symbolic blends are transient states between (nearly) discrete input and output states. I will discuss the relation between (i) faithfulness between symbolic representations and (ii) continuous similarity of the activation patterns realizing those representations, illustrating with general patterns in speech errors. I will close with speculations about potential roles of non-transient symbolic blends in syntactic competence and performance.