<p> Pupil dilation measures provide a useful index of test-taking processes. Prior research has established a simple positive relationship between pupil dilation magnitude and (i) threat levels, (ii) task difficulty levels, and (iii) working memory capacity. Surprisingly few studies have investigated the interaction of these three pupil response drivers. Do they add in a linear fashion, like separate weights on a single scale (as the "load" metaphor suggests), or is their relationship more complicated? To test of this question, I used a 2 X (2 X 3) mixed experimental design with random assignment to working memory resource depletion and nondepletion groups. These groups completed two versions of the same task, where response inhibition is required repeatedly in the depleting but is not required in the nondepleting version. Next, all subjects completed a test (90 factor-multiple judgment items) that employed two levels of difficulty (easy and difficult) and three levels of threat (safe, partially cued threat, and fully cued threat). Test-taking pupil data were collected at 60 Hz using a Tobii eye-tracker. Results indicated that levels of threat and task difficulty independently contribute to pupil response magnitude and they do not moderate one another. Apparently, the effects of difficulty and threat are not moderated by resource depletion; however, this study lacked power to detect anything less than a strong depletion effect. Results indicate that test-taking pupil responses are sensitive to testing conditions (e.g., threat and difficulty), but it remains unclear whether these responses are also sensitive to priming conditions (e.g., resource depletion).</p>

<p> Authentication is the process of validating the identity of an entity, e.g., a person, a machine, etc.; the entity usually provides a proof of identity in order to be authenticated. When the entity &mdash; to be authenticated &mdash; is a human, the authentication process is called end-user authentication. Making an end-user authentication usable entails making it easy for a human to obtain, manage, and input the proof of identity in a secure manner. In machine-to-machine authentication, both ends have comparable memory and computational power to securely carry out the authentication process using cryptographic primitives and protocols. On the contrary, as a human has limited memory and computational power, in end-user authentication, cryptography is of little use. Although password based end-user authentication has many well-known security and usability problems, it is the de facto standard. Almost half a century of research effort has produced a multitude of end-user authentication methods more sophisticated than passwords; yet, none has come close to replacing passwords. </p><p> In this dissertation, taking advantage of the built-in sensing capability of smartphones, we propose an end-user authentication framework for smartphones &mdash; called ePet &mdash; which does not require any active participation from the user most of the times; thus the proposed framework is highly usable. Using data collected from subjects, we validate a part of the authentication framework for the Android platform. For web authentication, in this dissertation, we propose a novel password creation interface, which helps a user remember a newly created password with more confidence &mdash; by allowing her to perform various memory tasks built upon her new password. Declarative and motor memory help the user remember and efficiently input a password. From a within-subjects study we show that declarative memory is sufficient for passwords; motor memory mostly facilitate the input process and thus the memory tasks have been designed to help cement the declarative memory for a newly created password. This dissertation concludes with an evaluation of the increased usability of the proposed interface through a between-subjects study.</p>

<p> Techniques to accurately measure situation awareness (SA) are important when designing systems that optimize operator performance. The two most prominent SA probe techniques vary based on screen visibility and situation pause during question presentation. The current study used four probe techniques based on all possible configurations of these factors. Air traffic control students controlled traffic in 10 scenarios that included all four probe techniques and a baseline no-probe condition across two degrees of automation. Probe questions varied on two levels of priority and specificity, creating four question types. Based on operator performance variations and subjective ratings, results support administration of probes with a visible screen and while the situation is paused. No method showed superior sensitivity to SA differences. Finally, the current study replicated findings that low priority information is offloaded to the environment and accessed as needed, supporting the situated approach towards SA.</p>

<p> When a person estimates their global (overall) performance on a test they just completed, low performers often overestimate their performance whereas high performers estimate more accurately or slightly underestimate. Thus, low performers have been described as 'unskilled and unaware' (Kruger &amp; Dunning, 1999). However, recent evidence (Hartwig &amp; Dunlosky, in press) demonstrates that low performers sometimes estimate accurately. What determines whether a participant estimates accurately vs. inaccurately remains unclear. Thus, the present research asks: What might participants use as the basis for their global estimates, and can it explain the accuracy of those estimates? One intuitive possibility is that participants use their response confidence in test items as the basis of their global estimates. A simple instantiation of this idea is described by the item-frequency hypothesis, which posits that participants compute the frequency of their high-confidence responses, and this frequency serves as an estimate of their global performance. A corollary of this hypothesis is that items that produce high confidence in wrong answers (i.e., false alarms, or FAs) will contribute to global overestimates, whereas items that produce low confidence in correct answers (i.e., misses) will contribute to global underestimates. Study 1 found preliminary support for the hypothesis, because the frequency of high-confidence responses on a typical trivia test was correlated with participants' global estimates, and the imbalance of FAs vs. misses predicted the accuracy of those estimates. To evaluate the hypothesis experimentally, Studies 2 and 3 manipulated the frequencies of FAs and misses that a trivia test was expected to yield, and participants were randomly assigned to receive one of the tests. Tests designed to yield many FAs (relative to misses) produced global overestimation, tests designed to yield more misses (relative to FAs) produced underestimation, and tests designed to yield a balance of FAs and misses produced accurate estimation. Thus, the selection of test items affects global estimates and their accuracy. The imbalance of FAs and misses could not explain all individual differences in estimation accuracy, but it nonetheless was a moderate predictor of global estimation accuracy. </p>

<p> Previous research has suggested that both alcohol cues and positive affect increase the tendency to incorporate false information into memory. This series of studies sought to determine if affect mediates the influence of alcohol cues on incorporation of false information into memory. Initially, a pilot study was completed to determine the individual differences that predict which individuals experience a heightening of positive affect following visualization exercises involving alcoholic beverages. Next, a study was conducted to determine if this affect increase from exposure to alcohol cues leads to increased acceptance of misinformation into memory. Participants' memories were tested while they were in the presence of an alcoholic or control beverage, rather than merely visualizing these beverages. The pilot study found that individuals engaging in alcohol thoughts exhibited a lower reduction in positive affect compared to those in the control condition. In addition, the relationship between cue exposure and positive affect was moderated by alcohol cognitions, such that individuals with stronger positive alcohol outcome expectancies experienced a greater boost in positive affect after engaging in an alcohol imagery exercise. However in study 1, there was no relationship between exposure to alcohol cues and change in positive affect. In addition, there was no influence of alcohol cognitions on change in affect. Cue exposure, alcohol cognition, and change in positive affect also showed no influence on responses to misinformation items. Regardless of cue type exposure, an overall misinformation effect was observed, whereas individuals made more errors on misinformation items while at the same time expressing more confidence in their responses to misinformation items.</p>

<p> The perception of visual motion is an integral aspect of many organisms' engagement with the world. In this dissertation, a theory for the perception of visual object-motion is developed. Object-motion perception is distinguished from objectless-motion perception both experimentally and theoretically. A continuous-time dynamical neural model is developed in order to generalize the findings and provide a theoretical framework for continued refinement of a theory for object-motion perception. Theoretical implications as well as testable predictions of the model are discussed.</p>

The present study investigated bilingual lexical organization in two groups of French-English bilinguals: (1) Compound bilinguals, who acquired both languages in early childhood and speak both with high proficiency; and (2) Subordinate bilinguals, who started speaking their second language during or after adolescence and have reduced L2 proficiency. Subjects were tested on a cross-language auditory primed lexical decision task containing translations and associated words with both cognate and noncognate equivalents. Both subject groups demonstrated significant translation and associative priming, indicating that both groups of subjects had access to a conceptual route of processing. However, no significant facilitation was found for cognates over noncognates in the auditory modality, contrary to previous studies using visual presentation. A general model of compound bilingual lexical organization is derived, and the results are discussed in terms of their implications for second language acquisition.

This study investigated the hypothesis that delayed first language acquisition impedes syntactic learning in a second language. English syntactic skills of two deaf groups and one control group were investigated. One group of deaf subjects acquired a first language on schedule in early childhood, American Sign Language (ASL), and commenced learning English at school age. The other deaf group had significantly delayed first language acquisition, and began learning both ASL and English at school. Two English tasks were administered, grammatical judgement and syntactic comprehension. The stimuli were grammatical and ungrammatical exemplars of six types of syntactic structure ranging from simple to complex. The results supported the hypothesis and were consistent across all tasks. The delayed, first language learners were significantly less accurate in grammatical judgement and comprehension and significantly slower in response latency. These findings indicate that early first language acquisition is critical for successful second language syntactic learning.

<p> Lack of common vocabulary has been an obstacle to the psychotherapy integration movement. This deficit has been particularly significant in the research on the psychotherapy relationship. The concept of meaningful involvement is central to the practice of reality therapy, a practice model developed by William Glasser, MD, which has not been studied extensively. The purpose of the present study was to contribute to a common vocabulary for psychotherapy integration and to clarify the definition of <i>meaningful involvement</i>. The selected research methodology was the framework method of narrative analysis coupled with the use of AnSWR, a computer-assisted data management and analysis tool. This methodology was applied to a written text, <i>Counseling with Choice Theory: The New Reality Therapy</i>. Results from the current study indicated that patterns of communication were most consistent with an instructional stance. These results were consistent with the instructional nature of reality therapy of psychotherapy, yet were not consistent with Glasser&rsquo;s focus on the therapeutic relationship as the central element of this school of psychotherapy. Further study is recommended on meaningful involvement within reality therapy in future research with data that allows for observation of nuances of communication, such as body language and tone of voice, is recommended to address this inconsistency.</p>

Three tasks of selective attention were administered to test inhibition, visuospatial selective attention, and Decision-making in subjects with Alzheimer's disease (AD). Compared to normal elderly controls (NECs), subjects were significantly slower on the visuospatial and inhibitory tasks. The inhibitory measure revealed the largest (proportional reaction time) group difference. There were no significant inter-task correlations, suggesting the potential to fractionate selective attention. / To assess the relationship between inhibition and atrophy in the anterior cingulate cortex (ACC), a manual segmentation was performed on T1 weighted MRI scans in NECs and AD subjects. We calculated the cerebrospinal fluid (CSF):grey matter ratio to obtain a biomarker of atrophy. The CSF:grey matter ratio was significantly greater in AD subjects than NECs. There was a significant correlation between task performance and the CSF:grey matter ratio in ADs, but not in NECs, suggesting that a relationship exists between inhibitory processes and atrophy in the ACC in AD.