Familiarity and Preference for Pitch Probability Profiles

We investigated familiarity and preference judgments of participants toward a novel musical system. We exposed participants to tone sequences generated from a novel pitch probability profile. Afterward, we either asked participants to identify more familiar or we asked participants to identify preferred tone sequences in a two-alternative forced-choice task. The task paired a tone sequence generated from the pitch probability profile they had been exposed to and a tone sequence generated from another pitch probability profile at three levels of distinctiveness. We found that participants identified tone sequences as more familiar if they were generated from the same pitch probability profile which they had been exposed to. However, participants did not prefer these tone sequences. We interpret this relationship between familiarity and preference to be consistent with an inverted U-shaped relationship between knowledge and affect. The fact that participants identified tone sequences as even more familiar if they were generated from the more distinctive (caricatured) version of the pitch probability profile which they had been exposed to suggests that the statistical learning of the pitch probability profile is involved in gaining of musical knowledge.

Design of Transparent Conducting Electrodes and Surface Relief Gratings for Plasmonic Polymer Solar Cells

As the concept of renewable energy becomes increasingly important in the modern society, a considerable amount of research has been conducted in the field of organic photovoltaics in recent years. Although organic solar cells generally have had lower efficiencies compared to silicon solar cells, they have the potential to be mass produced via solution processing. A common polymer solar cell architecture relies on the usage of P3HT (electron donor) and PCBM (electron acceptor) bulk heterojunction. One of the main issues with this configuration is that in order to compensate for the high exciton recombination rate, the photoactive layer is often made very thin (on the order of 100 $%). This results in low solar cell photocurrents due to low absorption. This thesis investigates a novel method of light trapping by coupling surface plasmons at the electrode interface via surface relief gratings, leading to EM field enhancements and increased photo absorption. Experimental work was first conducted on developing and optimizing a transparent electrode of the form &'()/+,/&'() to replace the traditional ITO electrode since the azopolymer gratings cannot withstand the high temperature processing of ITO films. It was determined that given the right thickness profiles and deposition conditions, the MAM stack can achieve transmittance and conductivity similar to ITO films. Experimental work was also conducted on the fabrication and characterization of surface relief gratings, as well as verification of the surface plasmon generation. Surface relief gratings were fabricated easily and accurately via laser interference lithography on photosensitive azopolymer films. Laser diffraction studies confirmed the grating pitch, which is dependent on the incident angle and wavelength of the writing beam. AFM experiments were conducted to determine the surface morphology of the gratings, before and after metallic film deposition. It was concluded that metallic film deposition does not significantly alter the grating morphologies.

Design of Transparent Conducting Electrodes and Surface Relief Gratings for Plasmonic Polymer Solar Cells

As the concept of renewable energy becomes increasingly important in the modern society, a considerable amount of research has been conducted in the field of organic photovoltaics in recent years. Although organic solar cells generally have had lower efficiencies compared to silicon solar cells, they have the potential to be mass produced via solution processing. A common polymer solar cell architecture relies on the usage of P3HT (electron donor) and PCBM (electron acceptor) bulk heterojunction. One of the main issues with this configuration is that in order to compensate for the high exciton recombination rate, the photoactive layer is often made very thin (on the order of 100 $%). This results in low solar cell photocurrents due to low absorption. This thesis investigates a novel method of light trapping by coupling surface plasmons at the electrode interface via surface relief gratings, leading to EM field enhancements and increased photo absorption. Experimental work was first conducted on developing and optimizing a transparent electrode of the form &'()/+,/&'() to replace the traditional ITO electrode since the azopolymer gratings cannot withstand the high temperature processing of ITO films. It was determined that given the right thickness profiles and deposition conditions, the MAM stack can achieve transmittance and conductivity similar to ITO films. Experimental work was also conducted on the fabrication and characterization of surface relief gratings, as well as verification of the surface plasmon generation. Surface relief gratings were fabricated easily and accurately via laser interference lithography on photosensitive azopolymer films. Laser diffraction studies confirmed the grating pitch, which is dependent on the incident angle and wavelength of the writing beam. AFM experiments were conducted to determine the surface morphology of the gratings, before and after metallic film deposition. It was concluded that metallic film deposition does not significantly alter the grating morphologies.

Investigating Multiple Roles of Vocal Confidence in Persuasion

Although persuasion often occurs via oral communication, it remains a comparatively understudied area. This research tested the hypothesis that changes in three properties of voice influence perceptions of speaker confidence, which in turn differentially affects attitudes according to different underlying psychological processes that the Elaboration Likelihood Model (ELM, Petty & Cacioppo, 1984), suggests should emerge under different levels of thought. Experiment 1 was a 2 (Elaboration: high vs. low) x 2 (Vocal speed: increased speed vs. decreased speed) x 2 (Vocal intonation: falling intonation vs. rising intonation) between participants factorial design. Vocal speed and vocal intonation influenced perceptions of speaker confidence as predicted. In line with the ELM, under high elaboration, confidence biased thought favorability, which in turn influenced attitudes. Under low elaboration, confidence did not bias thoughts but rather directly influenced attitudes as a peripheral cue. Experiment 2 used a similar design as Experiment 1 but focused on vocal pitch. Results confirmed pitch influenced perceptions of confidence as predicted. Importantly, we also replicated the bias and cue processes found in Experiment 1. Experiment 3 investigated the process by which a broader spectrum of speech rate influenced persuasion under moderate elaboration. In a 2 (Argument quality: strong vs. weak) x 4 (Vocal speed: extremely slow vs. moderately slow vs. moderately fast vs. extremely fast) between participants factorial design, results confirmed the hypothesized non-linear relationship between speech rate and perceptions of confidence. In line with the ELM, speech rate influenced persuasion based on the amount of processing. Experiment 4 investigated the effects of a broader spectrum of vocal intonation on persuasion under moderate elaboration and used a similar design as Experiment 3. Results indicated a partial success of our vocal intonation manipulation. No evidence was found to support the hypothesized mechanism. These studies show that changes in several different properties of voice can influence the extent to which others perceive them as confident. Importantly, evidence suggests different vocal properties influence persuasion by the same bias and cue processes under high and low thought. Evidence also suggests that under moderate thought, speech rate influences persuasion based on the amount of processing.