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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Vocal Timbre Influences Memory for Melodies

Weiss, Michael William 04 January 2012 (has links)
Several studies have demonstrated that melody recognition is reduced when the timbre (instrument) changes between exposure and test, but no study has evaluated the possibility that different timbres have differential effects on melody recognition. The current study evaluated adults’ recognition and liking of unfamiliar Irish melodies presented in four timbres: two familiar (voice, piano) and two less familiar (banjo, marimba). After exposure to a set of melodies, participants judged whether each melody from a larger set (original and novel) was old or new. Melodies presented vocally were remembered significantly better than those presented instrumentally even though they were liked less. The findings confirm that surface features of music and abstract, relational features are processed jointly as well as separately.
32

The Effects of Memory Remoteness on Recall and Recognition: Development of a Novel Measure of Naturalistic Memory

Armson, Michael 01 December 2011 (has links)
The current study introduced a new measure for the study of naturalistic memory, which involved the use of a homogeneous, controlled event for all participants. We tested participants’ memory for this so-called staged event with both the Autobiographical Interview (AI) and our novel receiver operating characteristic (ROC) task. Statistical analyses indicated that scores on the AI and on our new ROC measure showed time sensitivity consistent with the literature. These data were difficult to interpret, however, because of a confound of age. We will need to age-match our groups before drawing any major conclusions. That said, we found a significant positive correlation between measures of recollection on both the AI and ROC task, which was a promising finding in terms of validating the new measure against an established procedure. Overall, our results suggest that assessing recall and recognition for a staged event is a viable method for studying naturalistic memory.
33

The “Gist” of Early Visual Processing

Chan, David 21 November 2012 (has links)
Visual information is processed by two separate visual pathways. One is the magnocellular visual pathway (M-pathway), which carries high temporal frequency information but low spatial frequency information. The other is the parvocellular visual pathway (P-pathway), which carries low temporal information but high spatial information. Kveraga and colleagues (2007) presented participants with high and low spatial frequency images and found that participants made faster and more accurate categorization responses to the low spatial frequency images. They hypothesized this was due to low spatial frequency “gist” information being rapidly carried by the M-pathway. Using diffuse light and hand posture manipulations, we replicated the advantage for low spatial frequency (LSF) images in both experiments, and also found a larger advantage for LSF information when biasing the M-pathway (using hand posture). We were unable to inhibit the M-pathway using red diffuse light. Thus, it does appear “gist” processing is uniquely carried by the M-pathway.
34

The Effects of 17B-estradiol on Cognition

Au, Sin Tung 20 November 2012 (has links)
A bilateral salpingo oophorectomy (BSO), removal of the ovaries, is recommended for carriers of BRCA1/2 mutations to reduce cancer risks. However, BSO induces surgical menopause, and is associated with an increased risk of dementia (Rocca et al., 2007a) and Parkinsonism (Rocca et al, 2007b). This study investigated the cognitive outcomes of BSO one to ten years post-surgically. The present dataset (n=37) revealed there was a significant difference between the BSO group and their age matched cohort on the Logical Memory task assessing verbal, episodic memory. Levels of E1G (estrogen metabolite) was a significant predictor of the RAVLT primacy subscale indicating higher levels were associated with better recall at the beginning of a list of words. Controlling for age, performance on the RAVLT A1 measuring short-term memory degraded further out from BSO. While limited by the sample size, results are consistent with reports of post-BSO cognitive changes (Vearncomb & Panchana, 2009).
35

Tactile Cues in the Control of Action: An Emphasis on Movement Initiation

Diamond, Jonathan 14 January 2010 (has links)
The ability to detect a tactile stimulus during movement is markedly decreased (e.g., tactile gating), yet it is unknown whether the stimulus influences motor output. In the present study, participants moved a mechanical slider as quickly and as accurately as possible to a target. Participants received low-level electrical stimulation on the index finger of the reaching limb at various offsets relative to movement initiation. Participants reported whether they perceived the tactile cue. It was hypothesized that the detection of the stimulus would be reduced and the stimulus would influence motor output. First, a typical time course and magnitude of sensory gating was found, supporting previous observations (e.g., Chapman & Beauchamp, 2006). Second, no influence of the stimulation on motor output was observed. It was concluded that the detection of tactile cues during a goal-directed reaching task is attenuated and this stimulation does not influence motor output.
36

The Impact of Infant Crying and Soothability on Cognition

Ryan Harrison, Maireanne 15 February 2010 (has links)
Perception of infant crying has been linked to the brain regions that are activated with stress and conflict monitoring, such as the anterior cingulate and amygdala. Whether the stress of cry perception affects cognitive processes is heretofore unknown. This research combines an experimental paradigm of an unsoothable infant cry task (Donovan, Leavitt, & Taylor, 2005) with a series of Rejection Stroop tasks (Dandeneau & Baldwin, 2004) with the expectation that perception of infant distress would deplete neural resources underlying the regulation of attention. Two studies were conducted on non-parent young adults and two studies were conducted on mothers of infants. Results indicated that the cry task causes negative affect and cognitive interference in non-parent young adults to a greater extent than does a musical stimulus, and that mothers of infants experience negative affect and cognitive interference comparable to the non-parent young adults.
37

Vocal Timbre Influences Memory for Melodies

Weiss, Michael William 04 January 2012 (has links)
Several studies have demonstrated that melody recognition is reduced when the timbre (instrument) changes between exposure and test, but no study has evaluated the possibility that different timbres have differential effects on melody recognition. The current study evaluated adults’ recognition and liking of unfamiliar Irish melodies presented in four timbres: two familiar (voice, piano) and two less familiar (banjo, marimba). After exposure to a set of melodies, participants judged whether each melody from a larger set (original and novel) was old or new. Melodies presented vocally were remembered significantly better than those presented instrumentally even though they were liked less. The findings confirm that surface features of music and abstract, relational features are processed jointly as well as separately.
38

The Effects of Memory Remoteness on Recall and Recognition: Development of a Novel Measure of Naturalistic Memory

Armson, Michael 01 December 2011 (has links)
The current study introduced a new measure for the study of naturalistic memory, which involved the use of a homogeneous, controlled event for all participants. We tested participants’ memory for this so-called staged event with both the Autobiographical Interview (AI) and our novel receiver operating characteristic (ROC) task. Statistical analyses indicated that scores on the AI and on our new ROC measure showed time sensitivity consistent with the literature. These data were difficult to interpret, however, because of a confound of age. We will need to age-match our groups before drawing any major conclusions. That said, we found a significant positive correlation between measures of recollection on both the AI and ROC task, which was a promising finding in terms of validating the new measure against an established procedure. Overall, our results suggest that assessing recall and recognition for a staged event is a viable method for studying naturalistic memory.
39

The Effects of 17B-estradiol on Cognition

Au, Sin Tung 20 November 2012 (has links)
A bilateral salpingo oophorectomy (BSO), removal of the ovaries, is recommended for carriers of BRCA1/2 mutations to reduce cancer risks. However, BSO induces surgical menopause, and is associated with an increased risk of dementia (Rocca et al., 2007a) and Parkinsonism (Rocca et al, 2007b). This study investigated the cognitive outcomes of BSO one to ten years post-surgically. The present dataset (n=37) revealed there was a significant difference between the BSO group and their age matched cohort on the Logical Memory task assessing verbal, episodic memory. Levels of E1G (estrogen metabolite) was a significant predictor of the RAVLT primacy subscale indicating higher levels were associated with better recall at the beginning of a list of words. Controlling for age, performance on the RAVLT A1 measuring short-term memory degraded further out from BSO. While limited by the sample size, results are consistent with reports of post-BSO cognitive changes (Vearncomb & Panchana, 2009).
40

The “Gist” of Early Visual Processing

Chan, David 21 November 2012 (has links)
Visual information is processed by two separate visual pathways. One is the magnocellular visual pathway (M-pathway), which carries high temporal frequency information but low spatial frequency information. The other is the parvocellular visual pathway (P-pathway), which carries low temporal information but high spatial information. Kveraga and colleagues (2007) presented participants with high and low spatial frequency images and found that participants made faster and more accurate categorization responses to the low spatial frequency images. They hypothesized this was due to low spatial frequency “gist” information being rapidly carried by the M-pathway. Using diffuse light and hand posture manipulations, we replicated the advantage for low spatial frequency (LSF) images in both experiments, and also found a larger advantage for LSF information when biasing the M-pathway (using hand posture). We were unable to inhibit the M-pathway using red diffuse light. Thus, it does appear “gist” processing is uniquely carried by the M-pathway.

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