Douglas J. K. Mewhort

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The authors present a computational model that builds a holographic lexicon representing both word meaning and word order from unsupervised experience with natural language. The model uses simple convolution and superposition mechanisms (cf. B. B. Murdock, 1982) to learn distributed holographic representations for words. The structure of the resulting(More)
The power function is treated as the law relating response time to practice trials. However, the evidence for a power law is flawed, because it is based on averaged data. We report a survey that assessed the form of the practice function for individual learners and learning conditions in paradigms that have shaped theories of skill acquisition. We fit power(More)
Three experiments studied the perception of tone sequences having various degrees of musical structure. Ratings of perceived structure and ease of recognition in transposition were both influenced by harmonic progression (as defined by music theory), the contour (directional changes in pitch), and the excursion or repetition pattern within the sequence. The(More)
We introduce and evaluate via a Monte Carlo study a robust new estimation technique that fits distribution functions to grouped response time (RT) data, where the grouping is determined by sample quantiles. The new estimator, quantile maximum likelihood (QML), is more efficient and less biased than the best alternative estimation technique when fitting the(More)
Part 1 concerns representation: We demonstrate pop-out for a target that can be distinguished from the distractors only by the relative position of its components and thereby show that simple shape information is represented preattentively. We discuss our findings in terms of theories of search and texture segregation. Part 2 concerns selection: We(More)
We tabulated upper- and lowercase letter frequency using several large-scale English corpora (approximately 183 million words in total). The results indicate that the relative frequencies for upper- and lowercase letters are not equivalent. We report a letter-naming experiment in which uppercase frequency predicted response time to uppercase letters better(More)
The repetition deficit associated with rapid serial visual presentation (RSVP) has been explained as a repetition-induced blindness, that is, as a perceptual or encoding failure. The repetition deficit was replicated in a standard free-recall RSVP task, and it was shown that participants were able to report the lost item when they were prompted with a(More)
The authors varied the similarity between negative probes and study items in a short-term item-recognition task. Current models treat similarity as a function of the number of occurrences of the probe's features in the study set, a factor that is often confounded with the number of the probe's features occurring in the study set. Unconfounded comparisons(More)