Marcy Lansman

Individual differences in the ability to focus and divide attention

Abstract This research deals with individual differences in the ability to focus and divide attention. Eighty-five subjects performed visual search and auditory detection tasks in three conditions: single channel, focused attention, and divided attention. Reaction time (RT) was fastest in the single channel condition, intermediate in the focused attention condition, and longest in the divided attention condition, and these effects were much stronger in the auditory than the visual task. Correlations among RTs in the three conditions were very high within modality (>.88), and lower between modalities (.5 to .6). The correlational data was well fit by a model that included separate factors for the visual and auditory tasks. Measures from the three attentional conditions within each modality loaded equally on these factors. The data provided no evidence for distinct abilities to divide or focus attention.

WE: A Writing Environment for Professionals,

Abstract : Technical and scientific professionals are writers. Regardless of title or job description, they write. We are developing a comprehensive Writing Environment (WE) for this application. In describing this system, we will emphasize five key concepts: The system is based on a cognitive model for written communication; The system is highly visual; The system was prototyped in Smalltalk and then ported to Objective C; The system will be used a series of cognitive experiments; and the system can be extended to other applications. The emphasis placed on cognitive aspects in this description probably needs more explanation. WE is one instance of an increasingly important kind of software that provides users with an environment in which to think or with functions that supplement human cognitive skills. To be successful, these intelligence augmenting systems must reflect the cognitive processes of the people using them.

Expectancy and dual-task interference.

This research deals with the relationship between expectancy and attention. In two experiments, expectancy concerning the modality of a probe stimulus was manipulated. In Experiment 1, the frequencies of probes in auditory and visual modalities were varied. In Experiment 2, a cue prior to each trial indicated the relative probabilities of the two types of probes. In both experiments, expectancy effects were observed in a single-task condition during which the subjects only task was to respond to the probes and in a dual-task condition in which probes were inserted in the study phase of a pattern recognition task. If maintaining an expectancy requires attention, then diverting attention from the probe task to the pattern recognition task should have attentuated the effects of expectancy. In fact, the pattern recognition task did not alter frequency effects but did significantly reduce cueing effects. We conclude that expectancy as determined by frequency results from automatic activation, whereas expectancy as determined by cueing involves attention.

Automatic and controlled attention processes in auditory target detection.

Shiffrin and Schneider proposed a general theory of attention that postulates the existence of automatic and controlled search processes. They concluded that automatic processes develop when the mapping between stimuli and responses is consistent and controlled processing occurs when the mapping is varied. The effects of consistent and varied mapping were examined in an auditory target detection task. Subjects listened for one or three target letters embedded in a stream of dichotic letter pairs. Subjects responded faster and made fewer errors under the consistent mapping (CM) condition than under the varied mapping (VM) condition, and the effect of memory set size decreased over practice in the CM condition but not the VM condition. The results are discussed in terms of automatic and controlled processes involved in recognition of target stimuli. A review of research on auditory target detection suggests that the development of automatic processes may account for some apparent discrepancies in the literature.