A study of selective attention in young autistic subjects

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on August 1, 2007)Vita.Thesis (Ph. D.) University of Missouri-Columbia 2006.Pertinence level of the information in the unattended channel is supposed to play an important role in the process of selective attention in normal subjects (Norman, 1968). The developmental disorder of autism has been found to affect different measures of attention, but the attributes of the information to be ignored have not been investigated. This study examines the effect of information pertinence in the distracting auditory channel on primary task performance in young autistic subjects as compared to normal controls. A dichotic listening procedure and a bimodal selective attention task were implemented. It was found that, although the autistic group performed as fast as control groups, it made more errors on the dichotic listening task even when matched on receptive language abilities. Post-hoc comparisons showed that the autism group had increased error rates with all verbal distracters. All groups were slowest and made the most errors when the irrelevant channel presentation was the participants' name or a negatively, emotionally charged word. The first one or two presentations of these stimuli seemed to attract the most attention. It was concluded that even though children with autism appear to orient to the same types of stimuli as control groups, they are at a disadvantage when processing verbal stimuli in general.Includes bibliographical reference

With development, list recall includes more chunks, not just larger ones.

The nature of the childhood development of immediate recall has been difficult to determine. There could be a developmental increase in either the number of chunks held in working memory or the use of grouping to make the most of a constant capacity. In 3 experiments with children in the early elementary school years and adults, we show that improvements in the immediate recall of word and picture lists come partly from increases in the number of chunks of items retained in memory. This finding was based on a distinction between access to a studied group of items (i.e., recall of at least 1 item from the group) and completion of the accessed group (i.e., the proportion of the items recalled from the group). Access rates increased with age, even with statistical controls for completion rates, implicating development of capacity in chunks. (PsycINFO Database Record (c) 2010 APA, all rights reserved

Rethinking Speed Theories of Cognitive Development Increasing the Rate of Recall Without Affecting Accuracy

Researchers have suggested that developmental improvements in immediate recall stem from increases in the speed of mental processes. However, that inference has depended on evidence from correlation, regression, and structural equation modeling. We provide counterexamples in two experiments in which the speed of spoken recall is manipulated. In one experiment, second-grade children and adults recalled lists of digits more quickly than usual when the lists were presented at a rapid rate of 2 items per second (items/s). In a second experiment, children received lists at a 1 item/s rate but half of them were successfully trained to respond more quickly than usual, and similar to adults' usual rate. Recall accuracy was completely unaffected by either of these response-speed manipulations. Although response rate is a strong marker of an individual's maturational level, it thus does not appear to determine immediate recall. There are important implications for developmental methodology

On the capacity of attention: Its estimation and its role in working memory and cognitive aptitudes

Working memory (WM) is the set of mental processes holding limited information in a temporarily accessible state in service of cognition. We provide a theoretical framework to understand the relation between WM and aptitude measures. The WM measures that have yielded high correlations with aptitudes include separate storage and processing task components, on the assumption that WM involves both storage and processing. We argue that the critical aspect of successful WM measures is that rehearsal and grouping processes are prevented, allowing a clearer estimate of how many separate chunks of information the focus of attention circumscribes at once. Storage-and-processing tasks correlate with aptitudes, according to this view, largely because the processing task prevents rehearsal and grouping of items to be recalled. In a developmental study, we document that several scope-of-attention measures that do not include a separate processing component, but nevertheless prevent efficient rehearsal or grouping, also correlate well with aptitudes and with storage-and-processing measures. So does digit span in children too young to rehearse