Novel Properties of Frustrated Low Dimensional Magnets with Pentagonal Symmetry

In the context of magnetism, frustration arises when a group of spins cannot find a configuration that minimizes all of their pairwise interactions simultaneously. We consider the effects of the geometric frustration that arises in a structure having pentagonal loops. Such five-fold loops can be expected to occur naturally in quasicrystals, as seen for example in a number of experimental studies of surfaces of icosahedral alloys. Our model considers classical vector spins placed on vertices of a subtiling of the two dimensional Penrose tiling, and interacting with nearest neighbors via antiferromagnetic bonds. We give a set of recursion relations for this system, which consists of an infinite set of embedded clusters with sizes that increase as a power of the golden mean. The magnetic ground states of this fractal system are studied analytically, and by Monte Carlo simulation.Comment: 7 pages, 7 figures, contribution to ICQ11 (Sapporo, Japan 2010) conference proceeding

When Online Courses Became the Student Union: Technologies for Peer Interaction and Their Association With Improved Outcomes During COVID-19

While a variety of learning technologies are presently available to facilitate student-to-student peer interactions and collaborative learning online, recent research suggests that students’ opportunities to interact with their peers were significantly reduced following the abrupt transition to remote instruction due to coronavirus disease. This raises concerns because peer interaction is known to be a key ingredient in effective online learning environments, and during remote instruction, the primary connection between a student and their identity as a member of a college community would have been online courses. In this study, we investigate whether and how collaborative technologies supported peer interaction, and students’ learning, during remote instruction. Specifically, we used results from a multicampus survey of students and instructors, as well as data from our online learning management system, to explore the use of collaborative tools at a large scale and their associations with student outcomes. Findings indicate that instructors, as was typical before the pandemic, generally favored individual learning activities over collaborative activities during campus closure. But in those situations where collaborative activities were present during remote instruction, triangulation analyses indicate that their use was related to improved performance as measured by instructors’ survey responses, by students’ performance in their courses, and by an increased sense of belonging among students

A Pandemic of Busywork: Increased Online Coursework Following the Transition to Remote Instruction is Associated with Reduced Academic Achievement

Under normal circumstances, when students invest more effort in their schoolwork, they generally show evidence of improved academic achievement.  But when universities abruptly transitioned to remote instruction in Spring 2020, instructors assigned rapidly-prepared online learning activities, disrupting the normal relationship between effort and outcomes.  In this study, we examine this relationship using data observed from a large-scale survey of undergraduate students, from logs of student activity in the online learning management system, and from students’ estimated cumulative performance in their courses (n = 4,636).  We find that there was a general increase in the number of assignments that students were expected to complete following the transition to remote instruction, and that students who spent more time and reported more effort carrying out this coursework generally had lower course performance and reported feeling less successful.  We infer that instructors, under pressure to rapidly put their course materials online, modified their courses to include online busywork that did not constitute meaningful learning activities, which had a detrimental effect on student outcomes at scale.  These findings are discussed in contrast with other situations when increased engagement does not necessarily lead to improved learning outcomes, and in comparison with the broader relationship between effort and academic achievement

A LAK of Direction Misalignment Between the Goals of Learning Analytics and its Research Scholarship

Learning analytics defines itself with a focus on data from learners and learning environments, with corresponding goals of understanding and optimizing student learning. In this regard, learning analytics research, ideally, should be characterized by studies that make use of data from learners engaged in education systems, should measure student learning, and should make efforts to intervene and improve these learning environments

Visual Search Asymmetry Due to the Relative Magnitude Represented by Number Symbols

In visual search tasks, physically large target stimuli are more easily identified among small distractors than are small targets among large distractors. The present study extends this finding by presenting preliminary evidence of a new search asymmetry: stimuli that symbolically represent larger magnitude are identified more easily among featurally equivalent distractors that represent smaller magnitude. Participants performed a visual search task using line-segment digits representing the numbers 2 and 5, and the numbers 6 and 9, as well as comparable non-numeric control stimuli. In three experiments, we found that search times are faster when the target is a digit that represents a larger magnitude than the distractor, although this pattern was not evident in one additional experiment. The results provide suggestive evidence that the magnitude of a number symbol can affect perceptual comparisons between number symbols, and that the semantic meaning of a target stimulus can systematically affect visual search

Expectations during the Perception of Auditory Rhythms

When someone hears regular, periodic sounds, such as drum beats, footsteps, or stressed syllables in speech, these individual stimuli tend to be grouped into a perceived rhythm. One of the hallmarks of rhythm perception is that the listener generates expectations for the timing of upcoming stimuli, which theorists have described as endogenous periodic modulations of attention around the time of anticipated sounds. By constructing an internal representation of a rhythm, perceptual processes can be augmented by proactively deploying attention at the expected moment of an upcoming stressed syllable, the next step in an observed stride, or during the stroke of a co-speech hand gesture. A hypothetical benefit of this anticipatory allocation of attention is that it might facilitate temporal integration across the senses, binding multisensory aspects of our experiences into a unified “now,” anchored by temporally-precise auditory expectations. The current dissertation examines this hypothesis, exploring the effects of auditory singletons, and auditory rhythms, on electrophysiological indices of perception and attention to a visual stimulus, using the flash-lag paradigm. An electroencephalography study was conducted, where sounds, either isolated or presented rhythmically, occurred in alignment with a task-relevant visual flash. Results suggest a novel dissociation between the multisensory effects of discrete and rhythmic sounds on visual event perception, as assessed by the N1 component of the event-related potential, and by oscillatory power in the beta (15–20 Hz) frequency range. This dissociation is discussed in the context of classic and contemporary research on rhythm perception, temporal orienting, and temporal binding across the senses, and contributes to a more refined understanding of rhythmically-deployed attention

The Cognitive Costs of Context: The Effects of Concreteness and Immersiveness in Instructional Examples

Prior research has established that while the use of concrete, familiar examples can provide many important benefits for learning, it is also associated with some serious disadvantages, particularly in learners’ ability to recognize and transfer their knowledge to new analogous situations. However, it is not immediately clear whether this pattern would hold in real world educational contexts, in which the role of such examples in student engagement and ease of processing might be of enough importance to overshadow any potential negative impact. We conducted two experiments in which curriculum-relevant material was presented in natural classroom environments, first with college undergraduates and then with middle-school students. All students in each study received the same relevant content, but the degree of contextualization in these materials was varied between students. In both studies, we found that greater contextualization was associated with poorer transfer performance. We interpret these results as reflecting a greater degree of embeddedness for the knowledge acquired from richer, more concrete materials, such that the underlying principles are represented in a less abstract and generalizable form