{ "items": [ "\n\n
Until now it has been a commonly held view that numbers are represented abstractly in the human brain. However, a recent imaging study challenged the existence of an abstract representation at least of digits and number words, at the brain level, and argued that previous studies and paradigms were not sensitive enough to detect deviations from abstract representation at the behavioural level. The current study addressed this issue with an analysis of distance and sequential effects in magnitude classification. Previous studies that used this paradigm did not find deviation from abstract representation for digits and number words (e.g., Dehaene, 1996; Schwarz & Ischebeck, 2000). However, in the current study a short stimulus-response interval was used, which reduced subjective expectancy and increased automatic processing. The current results showed deviation from abstract representation in both reaction time and accuracy and therefore support the idea that nonabstract representations of numbers do exist.
\n \n\n \n \nIn the study of basic and high-level cognitive functions, neuroscientists, psychologists, and philosophers have tended to focus on normal psychological processes and on deficits in these processes, whereas the study of exceptional abilities has been largely neglected. Here the authors emphasize the value of researching exceptional abilities. They make the case that studies of exceptional representations, such as of time, number, and space in synesthesia, can provide us with insights regarding the nature of the neurocognitive mechanisms of these dimensions, as well as their developmental, evolutionary, and cultural origins.
\n \n\n \n \nLittle is currently known about the postnatal emergence of functional cortical networks supporting complex perceptual and cognitive skills, such as face processing. The present study examined the emergence of the core cortical network underlying face processing in younger and older school-age children as well as young adults. Participants performed 3 functional magnetic resonance imaging target detection tasks where they either had to detect a specific facial identity, expression, or direction of eye gaze in a stream of consecutively presented faces. We compared the connectivity of the face network using dynamic causal modelling and observed that it emerges gradually during childhood. Further, we found that while the relative strength of functional network connections were differentially modulated by task demands in adults, there was no such modulation of this network in either older or younger children. These results were independent of the behavioral performance in the 3 age groups. We suggest that the emergence of the face network is due to continuous specialization and fine-tuning within the regions of this network. The current results have important implications for future studies investigating trajectories of brain development and cortical specialization both in typically and atypically developing populations.
\n \n\n \n \nNumber-form synesthetes consciously experience numbers in spatially-defined locations. For non-synesthete individuals, a similar association of numbers and space appears in the form of an implicit mental number line as signified by the distance effect-reaction time decreases as the numerical distance between compared numbers increases. In the current experiment, three number-form synesthetes and two different non-synesthete control groups (Hebrew speaking and English speaking) performed a number comparison task. Synesthete participants exhibited a sizeable distance effect only when presented numbers were congruent with their number-form. In contrast, the controls exhibited a distance effect regardless of congruency or presentation type. The findings suggest that: (a) number-form synesthesia impairs the ability to represent numbers in a flexible manner according to task demands; (b) number-form synesthesia is a genuine tangible experience, triggered involuntarily; and (c) the classic mental number line can be more pliable than previously thought and appears to be independent of cultural-lingo direction.
\n \n\n \n \nWhether the human brain is equipped with a special neural substrate for numbers, or rather with a common neural substrate for processing of several types of magnitudes, has been the topic of a long-standing debate. The present study addressed this question by using functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) together with the size-congruity paradigm, a Stroop-like task in which numerical values and physical sizes were varied independently. In the fMRI experiment, a region-of-interest analysis of the primary motor cortex revealed interference effects in the hemisphere ipsilateral to the response hand, indicating that the stimulus-stimulus conflict between numerical and physical magnitude is not completely resolved until response initiation. This result supports the assumption of distinct comparison mechanisms for physical size and numerical value. In the ERP experiment, the cognitive load was manipulated in order to probe the degree to which information processing is shared across cognitive systems. As in the fMRI experiment, we found that the stimulus-stimulus conflict between numerical and physical magnitude is not completely resolved until response initiation. However, such late interaction was found only in the low cognitive load condition. In contrast, in the high load condition, physical and numerical dimensions interacted only at the comparison stage. We concluded that the processing of magnitude can be subserved by shared or distinct neural substrates, depending on task requirements.
\n \n\n \n \nThree experiments were carried out to investigate the effects upon subsequent recall of categorizing a stimulus at presentation by one of its attributes. The results indicated that a previously reported finding of categorized cue superiority for integral stimuli in an incidental learning paradigm may not be a robust one. Two experiments employed either intentional or incidental learning paradigms. In both, attributes that had been categorized at presentation did not differ in effectiveness as subsequent recall cues from those that had not. In a third experiment, with incidental learning, categorized cues were less effective than uncategorized cues. Thus, observed effects of categorization appear to be sensitive to minor differences in experimental procedure between studies. \u00a9 1980 Psychonomic Society, Inc.
\n \n\n \n \nIt has recently been proposed that global processing precedes local processing of a visual scene even when the local and the global aspects are similar in nature (e.g., both alphabetic). The two types of processing were compared here in four different ways, for stimuli with many and with few local elements (i.e., differing sparsities). These methods consisted of assessing naming latency, intrastimulus Stroop-like interference, intermodality Stroop-like interference, and phenomenal judgment. The results of four experiments were consistent in demonstrating global processing priority for many-lement stimuli but local processing priority for few-element stimuli. \u00a9 1979 Psychonomic Society, Inc.
\n \n\n \n \nFour experiments were carried out in which the probability of free recall of words as a function of serial position within lists was examined. The lists were presented either auditorily or visually, with subjects either silent or engaged in irrelevant articulation, and with recall either immediate or after an auditory or visual intervening task. The results provide evidence for the presence of modality-specific capacity limitations in primary memory, and also indicate that forgetting may occur in a last-in, first-out manner. \u00a9 1979 Springer-Verlag.
\n \n\n \n \nThe technique of Waugh & Norman (1965) is widely used in measuring the capacity of primary memory. Watkins (1974) has proposed a modification of the technique which takes into account registration failure. A further modification is proposed which takes into account findings of negative recency in delayed recall.
\n \n\n \n \nTwo experiments were carried out to investigate whether the immediate digit span measure traditionally used in the assessment of individual differences in cognition is a good predictor of performance on other memory tasks. In the first experiment, it was found that subjects' digit spans were not significantly related to their performances on either short-term or longterm memory tasks, or to theoretical measures of their memory store capacities. Memory for the temporal occurrence of events, however, proved to be positively correlated with digit span. A second experiment confirmed that digit span was correlated with memory for the temporal occurrence of events, but not with item memory. Thus it was concluded that an individual's digit span reflects his ability to retain information about the order of a sequence of events rather than the capacity of his short- or long-term memory. \u00a9 1978 Psychonomic Society, Inc.
\n \n\n \n \nTheoretical controversy surrounds the issue of whether or not silent reading involves speech recoding. This was investigated in two experiments by assessing performance on a Stroop color-word task carried out with subjects either silent or articulating irrelevantly (saying \"bla\" continuously). It was found that the usual decrement in performance resulting from lack of congruency between ink color and color word was attenuated in the articulation condition. The results provide evidence for the presence of speech recoding in silent reading. As a second test of this hypothesis, the Stroop task was also carried out in conjunction with either a graphemic or a phonemic task. The usual decrement in performance was attenuated more by the phonemic than by the graphemic task, therefore providing further support for the hypothesis. The relationship between individual differences in Stroop performance and those in reading speed and in personality (as assessed by the Eysenck Personality Questionnaire) were also examined. \u00a9 1978 Psychonomic Society, Inc.
\n \n\n \n \nThe first of two experiments measured the performance of 27 subjects on pairs of concurrent verbal tasks. Subjects monitored auditory sentences for stop consonants, adjectives, or time reference words (primary task) while reading randomized, syntactically correct but semantically anomalous, or normal English passages (secondary task). The results were in conflict with several models of attention but were in quantitative agreement with a linear law of attention-sharing between verbal tasks: Performance on a secondary task when combined with a primary task is proportional to performance on the secondary task in isolation. The primary tasks were unimpaired with the exception of the detection of stop consonants. The second experiment indicated that the decrement with stop consonants was not due to differences in resource/data limitations; it may result from demands upon a proposed fine-timing processor. \u00a9 1977 Academic Press, Inc. All rights reserved.
\n \n\n \n \n