Analysis of word comprehension in a case of pure word deafness

A case of pure word deafness due to a left temporal infarct is reported. The results of dichotic tests suggest that auditory verbal material may be processed in the right hemisphere. The inability to repeat nonsense words, the frequent semantic paraphasias in real-word repetition tasks, and the capacity to give a partial account of the meaning of a word that the patient cannot repeat show that despite the impairment of the phonological analysis, lexical semantic processing is possible. An attempt is made to demonstrate that the patient resorts to this semantic processing and that this reflects the linguistic competence of the right hemisphere.     

A tutorial on some issues and methods in serial pattern research

In a review of major trends in serial pattern research, the issue of structural ambiguity and its relationship to representations of hierarchical and nonhierarchical patterns is considered. Also discussed is the role of various kinds of serial rules that can relate events within a sequence (e.g., nominal, ordinal, interval rules), as well as new developments in representing time relationships. Some practical problems that arise in the study of perception of serial structure are shown to involve its formal specification and the enlistment of appropriate controls. Major pitfalls are illustrated using recent research with music-like patterns (e.g., Deutsch, 1980).     

Readiness for pronunciation during the reading process

The task proposed to the S consisted of reading a series of three numbers projected on a screen. Depending on the series presented, the number projected at the center (test) required one or more syllables to be pronounced. The results show that the more syllables it takes to pronounce it, the longer the eye fixation on that number lasts. This suggests that a mechanism of readiness for pronunciation co-occurs with visual processing.     

Rate and structure in memory for auditory patterns

Musically knowledgeable listeners heard auditory patterns based on sets of six (Study 1) or eight tones (Study 2). In the first study, listeners ordered events from patterns generated by hierarchical rule trees and which possessed different pitch space and time structures: one type (nondistance nested) was more likely to produce auditory streaming than the other (distance nested). In the second study, different listeners reconstructed pitch intervals contained in one of eight patterns. Patterns differed according to (1) levels of pitch distance occur), (2) levels of pattern contour (two), and (3) rate (two). In both studies, fast patterns with many large pitch distances were more difficult to recollect. Listeners in the second study telided to “telescope” pitch distances. Most difficult were those rapid sequences with large patch intervals combined into a changing contour (nondistance nested); these patterns streamed. A third study replicated effects due to differences in pitch distances observed in Study 2. Results were interpreted in terms of a rhythmic theory of memory.     

Cross-species differences in color categorization

Berlin and Kay (1969) found systematic restrictions in the color terms of the world’s languages and were inclined to look to the primate visual system for their origin. Because the visual system does not provide adequate neurophysiological discontinuities to supply natural color category boundaries, and because recent evidence points to a linguistic origin (Davidoff, Davies, & Roberson, 1999), a new approach was used to investigate the controversial issue of the origin of color categories. Baboons and humans were given the same task of matching-to-sample colors that crossed the blue/green boundary. The data and consequent modeling were remarkably clear-cut. All human subjects matched our generalization probe stimuli as if to a sharp boundary close to the midpoint between their training items. Despite good color discrimination, none of the baboons showed any inclination to match to a single boundary but rather responded with two boundaries close to the training stimuli. The data give no support to the claim that color categories are explicitly instantiated in the primate color vision system.     

Learning under stress: how does it work?

The effects of stress on learning and memory are not always clear: both facilitating and impairing influences are described in the literature. Here we propose a unifying theory, which states that stress will only facilitate learning and memory processes: (i) when stress is experienced in the context and around the time of the event that needs to be remembered, and (ii) when the hormones and transmitters released in response to stress exert their actions on the same circuits as those activated by the situation, that is, when convergence in time and space takes place. The mechanism of action of stress hormones, particularly corticosteroids, can explain how stress within the context of a learning experience induces focused attention and improves memory of relevant information.     

Impairment of syntax and lexical semantics in a patient with bilateral paramedian thalamic infarction

Bilateral vascular thalamic lesions are rare. Although a variety of neurobehavioral manifestations have been described, the literature is less documented with regard to accompanying linguistic disturbances. This article presents an in-depth neurolinguistic analysis of the language symptoms of a patient who incurred bilateral paramedian ischemic damage of the thalamus. In the post-acute phase of the stroke, a unique combination of transcortical sensory aphasia with syntactic impairment was found. Because of this atypical semiological association, additional analyses of spontaneous speech were performed. In spite of the typological affinity with the grammatic characteristic of marked simplification of syntax observed in Broca's aphasia, only a wordclass specific, lexical-semantic deficit for verbs was objectified. The hypothesis that lexical-semantic disturbances in our patient might result from a functional deafferentiation of both thalami with the frontal lobe is supported by: (1) associated neuropsychological deficits of frontal origin and (2) frontal-like behavioral disturbances.     

Higher order pattern structure influences auditory representational momentum

Representational momentum refers to the phenomenon that observers tend to incorrectly remember an event undergoing real or implied motion as shifted beyond its actual final position. This has been demonstrated in both visual and auditory domains. In 5 pitch discrimination experiments, listeners heard tone sequences that implied either linear, periodic, or null motions in pitch space. Their task was to judge whether the pitch of a probe tone following each sequence was the same or different from the final sequence tone. Results suggested that listeners made errors consistent with extrapolation of coherent pitch patterns (linear, periodic) but not with incoherent (null) ones. Hypotheses associated with internalized physical principles and pattern-based expectations are discussed.