An Interactive Activation Model of the Effect of Context in Perception, Part 1
University of California, San Diego, Center for Human Information Processing, 1980 - Perception - 95 pages
This report is the first part of a two-part series introducing an interactive activation model of context effects in perception. In this part, is developed the model for the perception of letters in words and other contexts and a number of experiments in the recent literature is applied. The model is used to account for the perceptual advantage for letters in words compared to single letters and letters in unrelated strings. In the model, these word-superiority effects are produced by feedback. The visual input produces partial activations of letters, which in turn produce partial activations of words. These activations then produce feedback to the letter level, reinforcing letter sequences which spell words. The model can account for the basic findings on the perception of pronounceable nonwords as well as words. The account is based on the idea that pseudowords can also activate representations of words, even though they do not match any word perfectly. As with word displays, feedback from the activated words reinforces the letters presented, thereby increasing their perceptibility. The model also accounts for the role of masking in determining the magnitude of the various effects, the fact that expectations influence perception of letters in words, and for the fact that effects of contextual constraint and letter cluster frequency are obtained under some conditions and not others.
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