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Thesis (Ph. D.)--University of Notre Dame, 2007. / Thesis directed by Brad S. Gibson for the Department of Psychology. "April 2007." Includes bibliographical references (leaves 119-134).

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 1999. / Vita. Includes bibliographical references (leaves 192-203).

Dissertation (Ph.D.)--The University of North Carolina at Greensboro, 2009. / Title from PDF t.p. (viewed May 17, 2010). Directed by David Teachout; submitted to the School of Music. Includes bibliographical references (p. 191-206).

Thesis (Ph.D.)--University of Delaware, 2005. / Principal faculty advisor: Hoffman, James E., Dept .of Psychology. Includes bibliographical references.

In this study, the effects of writing ability and mode of discourse of cognitive capacity engagement were investigated. Sixty-three college freshmen of varying writing abilities (basic, average, and honors) were randomly assigned to experimental treatments (descriptive writing, narrative writing, and persuasive writing). Using the secondary task method, it was found that writing ability differentially affects cognitive capacity engagement across modes. For example, honors writers were least engaged when writing descriptive essays but were most engaged when writing persuasive essays whereas average writers were most engaged when writing descriptive essays but were least engaged when writing narrative essays. Analytic quality scores and engagement were related and results were interpreted in the context of schema theory to estimate the learning potential of a given mode of discourse. Also, engagement and syntactic complexity treasures were related. It was found that as words per clause increased, engagement also increased; whereas, as clauses per T-unit increased, engagement decreased. / Ed. D.

The endogenous, or voluntary, control of visuospatial attention relies upon interactions within a frontoparietal dorsal attention network (DAN) and this network’s top-down influence on visual occipital cortex (VOC). While these interactions have been shown to occur during attention tasks, they are also known to occur to some extent at rest, but the degree to which task-related interactions reflect either modulation or reorganization of such ongoing intrinsic interactions is poorly understood. In addition, it is known that in spatial neglect—a syndrome following unilateral brain lesions in which patients fail to attend to the contralesional side of space—symptom severity covaries with disruptions to intrinsic interhemispheric interactions between left and right homologous regions of the DAN; however, similar covariance with disruptions to intrahemispheric interactions within the DAN, and between the DAN and VOC, has not been demonstrated. These issues are addressed herein via the measurement of both undirected and directed functional connectivity (UFC, DFC) within the DAN and between the DAN and VOC. UFC and DFC were derived from correlations of, and multivariate vector autoregressive modeling of, fMRI BOLD time-series, respectively. Time-series were recorded from individuals performing an anticipatory visuospatial attention task and individuals at rest, as well as from stroke patients either with or without neglect and age-matched healthy controls. With regard to the first issue, the results show that relative to rest, top-down DAN-to-VOC influence and within-DAN coupling are elevated during task performance, but also that intrinsic connectivity patterns are largely preserved during the task. With regard to the second issue, results show that interhemispheric imbalances of intrahemispheric UFC and DFC both within the DAN and between the DAN and VOC strongly correlate with neglect severity, and may co-occur with functional decoupling of the hemispheres. This work thus demonstrates that the intrinsic functional integrity of the DAN and its relationship to VOC is crucial for the endogenous control of visuospatial attention during tasks, and that the compromise of this integrity due to stroke likely plays a role in producing spatial neglect. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

A common metaphor for visual attention is the spotlight (Posner, 1980). It follows from the spotlight metaphor and other similar models (e.g., zoom-lens model; Eriksen and Yeh, 1985) that attention can, according to task-demands, be constricted into a focused beam (i.e., analogous to selective attention) or dilated to encompass a larger breadth (i.e., analogous to divided attention). It is currently unclear how variations in perceptual load of a display affect the FFOV. Lavie (1995; Lavie et al., 2004) proposed that the critical determinant of selective attention (i.e., a constriction of the FFOV) was the perceptual load imposed by the taskselective attention is a necessary outcome of limited perceptual processing capacity. Age-related differences in perceptual processing capacity (e.g., Maylor and Lavie, 1998) may then explain observed age-related differences in FFOV size (e.g., Ball, Beard, Roenker, Miller, and Griggs, 1988). The current study examined how perceptual load and aging affected the FFOV. Younger and older participants viewed brief displays in which they engaged in two tasks: the first task was a perceptual load manipulation, while the second task was a measure of the FFOV. Multiple measures of peripheral task performance suggest that the size of the FFOV for older adults was significantly reduced by increasing perceptual load and this effect of load was greater with increasing distance from fixation. As predicted from the perceptual load model, when perceptual load of the task increased, perceptual sensitivity for the distant peripheral task decreased for older adults. This decrease was greater when the task was farther from fixationindicative of a shrinking spotlight. However, for younger adults, increasing load did not affect peripheral task performance. This age-related difference may be attributable to older adults reduced perceptual processing capacity. The current results support the notion that older adults reduced perceptual processing capacity may be one cause of their reduced FFOV. Limitations of the current study as well as future research are discussed.

Cognitive control allows us to function in a world filled with constant stimulation. For example, the act of reading a book requires the ability to inhibit irrelevant information while focusing attention towards the letters on the page. Our cognitive control system regulates what information receives attention and what is denied resources. The goal of the current paper is to investigate the mechanisms underlying the activation and maintenance of the control system and how this process changes in healthy aging. First, the ability of younger and older adults to activate and maintain control in response to trial type manipulations is investigated. Second, improvements are made to recent experimental evidence suggesting younger adults are able to modulate performance based on specific stimulus history. Third, this work is extended to an older population suggesting the ability to modulate performance based on specific stimulus history is maintained in healthy aging. Finally, it is demonstrated that current theories of control fail to account for age-related differences in performance based on the comparison of trial type and specific stimulus manipulations.

This thesis presents data which support cochlear involvement in attentional listening. It has been previously proposed that the descending auditory pathways, in particular the medial olivocochlear system, play a role in reducing the cochlea's response to noise in a process known as antimasking. This hypothesis was investigated in human subjects for its potential impact on the detection of signals in noise following auditory cues. Three experimental chapters (Chapters 3, 4 and 5) are described in this thesis. Experiments in the first chapter measured the effect of acoustic cues on the detection of subsequent tones of equal or different frequency. Results show that changes in the ability to detect signals following auditory cues are the result of both enhanced detection for tones at the cued frequency, and suppressed detection for tones at non-cue frequencies. Both effects were measured to be in the order of ~3 dB. This thesis has argued that the enhancement of a cued tone is the implicit result of an auditory cue, while suppression of a probe tone results from the expectation of a specific frequency based on accumulated experience of a listening task. The properties of enhancement support the antimasking hypothesis, however, the physiological mechanism for suppression is uncertain. In the second experimental chapter, auditory cues were replaced with visual cues (representing musical notes) whose pitch corresponded to the target frequency, and were presented to musician subjects who possessed absolute or relative pitch. Results from these experiments showed that a visual cue produces the same magnitude of enhancement as that produced by an acoustic cue. This finding demonstrates a cognitive influence on the detection of tones in noise, and implicates the role of higher centres such as those involved in template-matching or top-down control of the efferent pathways. The final experimental chapter repeated several of the experiments from the first chapter on subjects with various forms of hearing loss. The results indicate that subjects with an outer hair cell deficit (concomitant with a sensorineural hearing loss) do not exhibit an enhancement of cued frequencies or a suppression of unexpected frequencies to the same extent as the normal-hearing subjects. In addition, one subject with a long-standing conductive hearing loss (with normal cochlear function) produced an enhancement equivalent to that of the normalhearing subjects. These findings also support the role of the medial olivocochlear system and the outer hair cells in antimasking. It is the conclusion of this thesis that enhancement most likely results from a combination of changes in receptive field characteristics, at various levels of the auditory system. The medial olivocochlear system is likely to be involved in unmasking a portion of the signal at the cochlear level, which may be influenced by both acoustic reflex pathways or higher centres of the brain.