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Barrett accepts high performing, academically engaged undergraduate students and works with them in collaboration with all of the other academic units at Arizona State University. All Barrett students complete a thesis or creative project which is an opportunity to explore an intellectual interest and produce an original piece of scholarly research. The thesis or creative project is supervised and defended in front of a faculty committee. Students are able to engage with professors who are nationally recognized in their fields and committed to working with honors students. Completing a Barrett thesis or creative project is an opportunity for undergraduate honors students to contribute to the ASU academic community in a meaningful way.

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Description
During speech, the brain is constantly processing and monitoring speech output through the auditory feedback loop to ensure correct and accurate speech. If the speech signal is experimentally altered/perturbed while speaking, the brain compensates for the perturbations by changing speech output in the opposite direction of the perturbations. In this

During speech, the brain is constantly processing and monitoring speech output through the auditory feedback loop to ensure correct and accurate speech. If the speech signal is experimentally altered/perturbed while speaking, the brain compensates for the perturbations by changing speech output in the opposite direction of the perturbations. In this study, we designed an experiment that examined the compensatory responses in response to unexpected vowel perturbations during speech. We applied two types of perturbations. In one condition, the vowel /ɛ/ was perturbed toward the vowel /æ/ by simultaneously shifting both the first formant (F1) and the second formant (F2) at 3 different levels (.5=small, 1=medium, and 1.5=large shifts). In another condition, the vowel /ɛ/ was perturbed by shifting F1 at 3 different levels (small, medium, and large shifts). Our results showed that there was a significant perturbation-type effect, with participants compensating more in response to perturbation that shifted /ɛ/ toward /æ/. In addition, we found that there was a significant level effect, with the compensatory responses to level .5 being significantly smaller than the compensatory responses to levels 1 and 1.5, regardless of the perturbation pathway. We also found that responses to shift level 1 and shift level 1.5 did not differ. Overall, our results highlighted the importance of the auditory feedback loop during speech production and how the brain is more sensitive to auditory errors that change a vowel category (e.g., /ɛ/ to /æ/).
ContributorsFitzgerald, Lacee (Author) / Daliri, Ayoub (Thesis director) / Corianne, Rogalsky (Committee member) / College of Health Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
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Description
Speech perception and production are bidirectionally related, and they influence each other. The purpose of this study was to better understand the relationship between speech perception and speech production. It is known that applying auditory perturbations during speech production causes subjects to alter their productions (e.g., change their formant frequencies).

Speech perception and production are bidirectionally related, and they influence each other. The purpose of this study was to better understand the relationship between speech perception and speech production. It is known that applying auditory perturbations during speech production causes subjects to alter their productions (e.g., change their formant frequencies). In other words, previous studies have examined the effects of altered speech perception on speech production. However, in this study, we examined potential effects of speech production on speech perception. Subjects completed a block of a categorical perception task followed by a block of a speaking or a listening task followed by another block of the categorical perception task. Subjects completed three blocks of the speaking task and three blocks of the listening task. In the three blocks of a given task (speaking or listening) auditory feedback was 1) normal, 2) altered to be less variable, or 3) altered to be more variable. Unlike previous studies, we used subject’s own speech samples to generate speech stimuli for the perception task. For each categorical perception block, we calculated subject’s psychometric function and determined subject’s categorical boundary. The results showed that subjects’ perceptual boundary remained stable in all conditions and all blocks. Overall, our results did not provide evidence for the effects of speech production on speech perception.
ContributorsDaugherty, Allison (Author) / Daliri, Ayoub (Thesis director) / Rogalsky, Corianne (Committee member) / College of Health Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
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Description

The brain continuously monitors speech output to detect potential errors between its sensory prediction and its sensory production (Daliri et al., 2020). When the brain encounters an error, it generates a corrective motor response, usually in the opposite direction, to reduce the effect of the error. Previous studies have shown

The brain continuously monitors speech output to detect potential errors between its sensory prediction and its sensory production (Daliri et al., 2020). When the brain encounters an error, it generates a corrective motor response, usually in the opposite direction, to reduce the effect of the error. Previous studies have shown that the type of auditory error received may impact a participant’s corrective response. In this study, we examined whether participants respond differently to categorical or non-categorical errors. We applied two types of perturbation in real-time by shifting the first formant (F1) and second formant (F2) at three different magnitudes. The vowel /ɛ/ was shifted toward the vowel /æ/ in the categorical perturbation condition. In the non-categorical perturbation condition, the vowel /ɛ/ was shifted to a sound outside of the vowel quadrilateral (increasing both F1 and F2). Our results showed that participants responded to the categorical perturbation while they did not respond to the non-categorical perturbation. Additionally, we found that in the categorical perturbation condition, as the magnitude of the perturbation increased, the magnitude of the response increased. Overall, our results suggest that the brain may respond differently to categorical and non-categorical errors, and the brain is highly attuned to errors in speech.

ContributorsCincera, Kirsten Michelle (Author) / Daliri, Ayoub (Thesis director) / Azuma, Tamiko (Committee member) / School of Sustainability (Contributor) / College of Health Solutions (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description

The cocktail party effect describes the brain’s natural ability to attend to a specific voice or audio source in a crowded room. Researchers have recently attempted to recreate this ability in hearing aid design using brain signals from invasive electrocorticography electrodes. The present study aims to find neural signatures of

The cocktail party effect describes the brain’s natural ability to attend to a specific voice or audio source in a crowded room. Researchers have recently attempted to recreate this ability in hearing aid design using brain signals from invasive electrocorticography electrodes. The present study aims to find neural signatures of auditory attention to achieve this same goal with noninvasive electroencephalographic (EEG) methods. Five human participants participated in an auditory attention task. Participants listened to a series of four syllables followed by a fifth syllable (probe syllable). Participants were instructed to indicate whether or not the probe syllable was one of the four syllables played immediately before the probe syllable. Trials of this task were separated into conditions of playing the syllables in silence (Signal) and in background noise (Signal With Noise), and both behavioral and EEG data were recorded. EEG signals were analyzed with event-related potential and time-frequency analysis methods. The behavioral data indicated that participants performed better on the task during the “Signal” condition, which aligns with the challenges demonstrated in the cocktail party effect. The EEG analysis showed that the alpha band’s (9-13 Hz) inter-trial coherence could potentially indicate characteristics of the attended speech signal. These preliminary results suggest that EEG time-frequency analysis has the potential to reveal the neural signatures of auditory attention, which may allow for the design of a noninvasive, EEG-based hearing aid.

ContributorsLaBine, Alyssa (Author) / Daliri, Ayoub (Thesis director) / Chao, Saraching (Committee member) / Barrett, The Honors College (Contributor) / College of Health Solutions (Contributor) / Harrington Bioengineering Program (Contributor)
Created2023-05
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Description
In the past, researchers have studied the elements of speech and how they work together in the human brain. Auditory feedback, an important aid in speech production, provides information to speakers and allows them to gain an understanding if the prediction of their speech matches their production. The speech motor

In the past, researchers have studied the elements of speech and how they work together in the human brain. Auditory feedback, an important aid in speech production, provides information to speakers and allows them to gain an understanding if the prediction of their speech matches their production. The speech motor system uses auditory goals to determine errors in its auditory output during vowel production. We learn from discrepancies between our prediction and auditory feedback. In this study, we examined error assessment processes by systematically manipulating the correspondence between speech motor outputs and their auditory consequences while producing speech. We conducted a study (n = 14 adults) in which participants’ auditory feedback was perturbed to test their learning rate in two conditions. During the trials, participants repeated CVC words and were instructed to prolong the vowel each time. The adaptation trials were used to examine the reliance of auditory feedback and speech prediction by systematically changing the weight of auditory feedback. Participants heard their perturbed feedback through insert earphones in real time. Each speaker’s auditory feedback was perturbed according to task-relevant and task-irrelevant errors. Then, these perturbations were presented to subjects gradually and suddenly in the study. We found that adaptation was less extensive with task-irrelevant errors, adaptation did not saturate significantly in the sudden condition, and adaptation, which was expected to be extensive and faster in the task-relevant condition, was closer to the rate of adaptation in the task-irrelevant perturbation. Though adjustments are necessary, we found an efficient way for speakers to rely on auditory feedback more than their prediction. Furthermore, this research opens the door to future investigations in adaptation in speech and presents implications for clinical purposes (e.g. speech therapy).
ContributorsLukowiak, Ariana (Author) / Daliri, Ayoub (Thesis director) / Rogalsky, Corianne (Committee member) / Sanford School of Social and Family Dynamics (Contributor) / College of Health Solutions (Contributor, Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
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Description
Past studies have shown that auditory feedback plays an important role in maintaining the speech production system. Typically, speakers compensate for auditory feedback alterations when the alterations persist over time (auditory motor adaptation). Our study focused on how to increase the rate of adaptation by using different auditory feedback conditions.

Past studies have shown that auditory feedback plays an important role in maintaining the speech production system. Typically, speakers compensate for auditory feedback alterations when the alterations persist over time (auditory motor adaptation). Our study focused on how to increase the rate of adaptation by using different auditory feedback conditions. For the present study, we recruited a total of 30 participants. We examined auditory motor adaptation after participants completed three conditions: Normal speaking, noise-masked speaking, and silent reading. The normal condition was used as a control condition. In the noise-masked condition, noise was added to the auditory feedback to completely mask speech outputs. In the silent reading condition, participants were instructed to silently read target words in their heads, then read the words out loud. We found that the learning rate in the noise-masked condition was lower than that in the normal condition. In contrast, participants adapted at a faster rate after they experience the silent reading condition. Overall, this study demonstrated that adaptation rate can be modified through pre-exposing participants to different types auditory-motor manipulations.
ContributorsNavarrete, Karina (Author) / Daliri, Ayoub (Thesis director) / Peter, Beate (Committee member) / College of Health Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05