This paper introduces a special issue of "Cognitive Science" initiated on the 25th anniversary of the publication of "Parallel Distributed Processing" (PDP), a two-volume work that introduced the use of neural network models as vehicles for understanding cognition. The collection surveys the core commitments of the PDP…

In a seminal 1977 article, Rumelhart argued that perception required the simultaneous use of multiple sources of information, allowing perceivers to optimally interpret sensory information at many levels of representation in real time as information arrives. Building on Rumelhart's arguments, we present the Interactive Activation…

This report is the first in a two-part series introducing an interactive activation model of context effects in perception. A model for the perception of letters in words and other contexts is described and applied to a number of experiments. It is proposed that the model accounts for (1) the perceptual advantage for letters in words compared to…

This report is the second in a two-part series introducing an interactive activation model of context effects in perception. In the first part, a model for the perception of letters in words and other contexts was described and applied to a number of experiments. This second part applies the same model to a number of new experiments designed to…

Mathematical analysis and computer simulation methods are used to show that interactive models of context effects can exhibit classical context effects if there is variability in the input to the network or the network itself. Interactive models represent hypotheses about information-processing dynamics leading to the global asymptotic behaviors…

A model of context effects in perception is applied to perception of letters. Perception results from excitatory and inhibitory interactions of detectors for visual features, letters, and words. The model produces facilitation for letters in pronounceable pseudowords as well as words and accounts for rule-governed performance without any rules.…

The duration and timing of the context is which letters occur is shown to influence the perceptibility of the target in experiments demonstrating that early on enhanced word presentations and pronounceable-pseudoword contexts increase letter perceptibility. The perceptibility of letters in strings sharing several or few letters with words is…

The cascade model of information processing is compatible with the relation between time and accuracy in speed-accuracy trade-off experiments. Findings regarding the additive factors methods led to reexamination of conclusions drawn from several studies about the locus of perceptual and attentional effects on processing. (Author/RD)