Hemispheric specialization for syntactic form

Pure nouns, verb-derived nouns, category-ambiguous words, and adjectives, all ending in -er, and matched for low and moderate-high frequency, were presented in each visual field to 24 normal, right-handed females. The four word classes were recognized at the same rate in the LVF, and at a significantly higher rate in the RVF. Contrary to earlier reports, there were no differences among pure nouns, verb-derived nouns, and category-ambiguous words, and effects appeared to be independent of word frequency. Neither hemisphere was demonstrated to give preferential access to the syntactic forms tested.     

Tests that discriminate between dyslexic and other learning-disabled boys

Dyslexic and nondyslexic boys within a single community's learning-disabled class were given a set of tests; performance on each of these tests has been reported to be significantly impaired in other dyslexic children compared to learning-disabled and normal groups. Linear discriminant function analysis revealed that error types rather than levels of performance best separated the carefully matched learning-disabled groups. Slow naming and high percentage of “dysphasic” errors characterized dyslexic boys. Visual temporal-spatial matching and “configuration-deficient” perceptual errors characterized the adequate readers who have other learning disabilities.     

Profiles of symbol-reading skills in organic patients

One (unitary) school of thought views all symbolic competences as closely related, while a rival (pluralistic) approach underscores the relative differences among modes of symbolic processing. To secure information on the plausibility of these competing hypotheses, matched groups of left- and right-hemisphere patients were given a visual symbol-recognition test. Subjects were required to choose the correctly depicted symbol among a set of four. The results challenge a strong version of the “unitary” hypothesis. What emerges instead is a view of symbol systems as a continuum: relatively linguistic symbol systems prove challenging for left-hemisphere patients, relatively nonlinguistic systems pose comparable difficulties for right-hemisphere patients. Contrary to hypothesis, the processing of numerical symbols poses special difficulty for right-hemisphere patients. Performance on trademarks—items which can be processed by linguistic or nonlinguistic strategies—suggests that organic patients with contrasting pathologies may adopt different processing strategies when confronting identical physical stimuli.     

A developmental study of the effects of irrelevant information on speeded classification

The study examined how well subjects were able to ignore the presence of irrelevant stimulus information as a function of age. Children aged 6, 9, and 12, as well as adult subjects sorted cards with one binary dimension relevant, and zero, one, or two dimensions irrelevant. Speed of classification was measured. Significant effects of age, sex, number of irrelevant dimensions, and relevant dimension on speed of classification were obtained, as well as a number of interactions of these variables. The most important finding was that the presence of irrelevant information interfered with the performance of the task by child subjects and that the magnitude of the interference declined with age. The results were interpreted as implying that developmental trends in attention may be most clearly demonstrated in tasks which require speeded processing of stimuli. The ease of administration of the speeded classification task, coupled with the clear developmental trends obtained, recommend this paradigm as a useful one with which to study the development of selective attention.     

A model of three-choice discrimination learning under complete and incomplete feedback conditions

The Bower and Trabasso model of concept identification was extended to cover problems in which three stimuli were presented simultaneously and S pointed to the one he thought was correct. The E gave complete feedback by indicating the correct stimulus, or incomplete feedback by saying “correct” or “wrong.” The model accurately accounted for the significant difference in total errors between the two feedback conditions by incorporating process assumptions reflecting the logical difference in information content of the two types of feedback. Using a single set of parameter estimates, the model made satisfactory quantitative predictions of several statistics for both feedback conditions. Some deviations from the model's predictions were found in the length of terminal error runs, indicating that Ss were possibly using memory more extensively than posited by the model.     

Backward conditioning as an extinction procedure

In two conditioned suppression experiments, rats received Pavlovian forward defense conditioning in which tonal conditioned stimuli (CSs) terminated with the onset of scrambled grid shock unconditioned stimuli (USs). After this experience, the rats then received a Pavlovian backward conditioning procedure in which the same USs now terminated with the onset of the same CSs. Although the two experiments differed greatly in terms of CS and US parameters, number of forward and backward pairings, and in terms of the general techniques used to establish and measure the Pavlovian conditioned response (CR), the results of both experiments agreed in showing that backward conditioning can indeed weaken a CR based on forward pairings. The results also show that, under some conditions, the backward procedure can be at least as effective in weakening an established CR as the traditional CS-alone extinction procedure; but, under other conditions, the backward procedure is less effective and leads to more spontaneous recovery than the CS-alone procedure.     

The duration and generalization of attraction

Tested in the present study were the propositions that attraction toward others is lasting and that liked and disliked individuals serve as a basis for liking others. On the first day, subjects received interpersonal evaluations (e.g., judging the intelligence of others) which supposedly had originated with an anonymous person. Following a delay of 1 to 3 days, the attraction of some of the subjects toward the anonymous person was assessed while the attraction of other subjects toward a second anonymous person, who presumably had also evaluated the subjects, was also assessed. These latter subjects were never exposed to the alleged evaluation by the second person. Attraction toward the first person tended to endure and to generalize to the second person.