A test of the Sophisticated Guessing Theory of word perception

Under difficult viewing conditions, a letter in a familiar word can be perceived more accurately than the same letter alone or in a string of unrelated letters. Sophisticated Guessing Theory asserts that perception is more accurate when a letter appears in a word because its identity is constrained by the identity of neighboring context letters. Experiment 1 tested the following prediction: A letter in a word should be perceived more accurately in strongly constraining word contexts than in weakly constraining word contexts. No such trend was found using a number of different measures of contextual constraint and perceptual accuracy. Experiment 2 verified that, with the same conditions used in Experiment 1 to test Sophisticated Guessing Theory, a strong perceptual advantage could be obtained for letters in words vs. letters alone or in unrelated-letter strings. Several alternative theories of word perception are discussed. The most attractive asserts that for words an additional higher-level perceptual code is formed that is more resistant to degradation than the code formed for letters.     

An integration of shifts toward risk and caution in gambling situations

Findings have been reported and replicated indicating group-induced caution at the racetrack and group-induced risk in blackjack gambling. The present research examined the effects of two consistent differences between the blackjack and racetrack situations: (a) the amount of money available to groups versus individuals; and (b) the number of bets made in the postbaseline session. It was found that group-induced caution can occur in the blackjack setting if groups have larger stakes than individuals, as was the case in the racetrack studies, and that this effect disappears over trials, due to group versus individual differences established in the previous blackjack studies. Since current explanations of choice shifts cannot account for the observed trial effects, it was suggested that traditional choice-dilemma material, on which these explanations are largely based, be examined for such effects. Implications of the possible outcomes of such an examination for current group polarization theory were discussed.     

POLITICS: Automated ideological reasoning

POLITICS is a system of computer programs which simulates humans in comprehending and responding to world events from a given political or ideological perspective. The primary theoretical motivations were: (1) the implemention of a functional system which applies the knowledge structures of Schank and Abelson (1977) to the domain of simulating political belief systems; (2) the development of a tentative theory of intentional goal conflicts and counterplanning. Secondary goals of the POLITICS project include developing a representation for belief systems, investigating cognitive processes such as goal-directed inferencing, and the integration of several types of knowledge representations into a functional system.     

Empirical evidence for narrative structure

Three experimental tasks—spontaneous telling of a story, reading, and parsing the story—were used to determine whether empirical data reflect the narrative structure of stories and can be predicted by a plot unit analysis of the stories (Lehnert, 1981). It was found that spontaneous pause durations at sentence breaks were highly correlated with the importance of these breaks as predicted theoretically. Only low correlations were obtained, however, when reading pause durations were correlated with the model. As for parsing values, the value of the correlation coefficients depended on whether stories had sufficient superficial linguistic cues to help the subjects in parsing. It was concluded that spontaneous pausing not only reflects the narrative structure of stories, but can be used as a guide to constructing theories of narrative structure as well as for deciding between competing theories.     

Further observations on the nature of prosopagnosia

Two new cases of prosopagnosia are described and compared with pertinent clinical material from the English language literature. The interpretation of this disorder most compatible with the clinical data appears to us to be that there is an underspecification of visuoperceptive information preventing both the formation of significant face images and the retrieval of well-known face memoranda existing within a relatively intact visual remote memory store. Failure of formation of immediate memoranda of similarly complex visual images is also commonly observed but does not seem to be a requirement for the symptom of prosopagnosia. Conceptualizing this abnormality as simply a material specific visual agnosia of images beyond the classifier level would still appear to be acceptable if less informative.