This paper proposes, empirically motivates and describes a pseudo-deterministic model of Human Language Processing (HLP) implemented in the ACT-R cognitive architecture (Anderson, 2007). The model reflects the integration of a highly parallel, probabilistic activation and selection mechanism and non-monotonic context accommodation mechanism (with limited parallelism) with what is otherwise a serial, deterministic processor. The overall effect is an HLP which presents the appearance and efficiency of deterministic processing, despite the rampant ambiguity which makes truly deterministic processing impossible.

Abstract. This paper describes a model of human language processing (HLP) which is incremental and interactive, in concert with prevailing psycholinguistic evidence. To achieve this, the model combines an incremental, serial, pseudo-deterministic processing mechanism, which relies on a non-monotonic mechanism of context accommodation, with an interactive mechanism that uses all available information in parallel to select the best choice at each choice point. 1