Categorization of Ambiguous Sentences as a Function of a Changing Prosodic Parameter: A Dynamical Approach

The present study investigates the dynamics of changes in interpretation of ambiguous sentences. The sentences used had alternative interpretations with different surface structures (bracketing). Continua were created by systematic manipulation of prosodic cues (relative foot duration), resulting in stimulus sentences that spanned the range between the two interpretations. Continua were presented to subjects who were requested to indicate as quickly as possible which meaning they perceived. The pattern of responses and response times revealed the presence of hysteresis. That is, when the values of prosodic parameters are congruent with both interpretations, the individual's recent history decides which meaning will be perceived. Thus, we can treat this categorization process as a transition from an initially stable meaning that loses stability with variations in prosody (our control parameter). The same underlying dynamics have been observed in studies of perception of syllables and aspects of visual perception. Apart from demonstrating the same characteristics of pattern formation at various levels of cognition, the study points to the usefulness of the dynamical approach in the investigation of language understanding.     

Verb effects during sentence processing.

We describe a study that explores how the properties of a verb's lexical entry contribute to on-line sentence processing. Schmauder (1991) has recently suggested that the verb-processing effects shown previously by Shapiro and his colleagues (Shapiro & Levine, 1990; Shapiro, Zurif, & Grimshaw, 1987; 1989) are not generalizable and may have been artifacts precipitated by experimental design factors. In this paper we logically analyze such a possibility and then present experiments that systematically investigate the design differences between the Shapiro et al. studies cited above and the Schmauder study. These analyses and experiments provide further evidence that verb effects during sentence processing are real, are to be expected given the architectures of recent parsing models, and are replicable using a dual task that is modified in reasonable ways.     

Effects of Acute Experimental Crowding1

Recent concern with population growth has begun to stimulate interest in the effect of crowding on humans. This report presents a model of crowding based on the concept of normative expectations concerning appropriate interaction distances. A study of acute experimental crowding was then conducted. Contrary to findings of prior research, the present study found that crowding produced arousal. Subsequent social behavior, however, was mediated by different sex-specific group processes. In general, crowded male groups displayed a competitive, fragmented orientation, whereas crowded women formed cohesive, cooperative groups. Contrary to preliminary expectations, subjects were differentially effected by crowding based on their seating position in the crowded room.