The experience of agency in sequence production with altered auditory feedback

When speaking or producing music, people rely in part on auditory feedback - the sounds associated with the performed action. Three experiments investigated the degree to which alterations of auditory feedback (AAF) during music performances influence the experience of agency (i.e., the sense that your actions led to auditory events) and the possible link between agency and the disruptive effect of AAF on production. Participants performed short novel melodies from memory on a keyboard. Auditory feedback during performances was manipulated with respect to its pitch contents and/or its synchrony with actions. Participants rated their experience of agency after each trial. In all experiments, AAF reduced judgments of agency across conditions. Performance was most disrupted (measured by error rates and slowing) when AAF led to an ambiguous experience of agency, suggesting that there may be some causal relationship between agency and disruption. However, analyses revealed that these two effects were probably independent. A control experiment verified that performers can make veridical judgments of agency.     

Adult Attachment Ratings (AAR): An Item Response Theory Analysis

The Adult Attachment Ratings (AAR) include 3 scales for anxious, ambivalent attachment (excessive dependency, interpersonal ambivalence, and compulsive care-giving), 3 for avoidant attachment (rigid self-control, defensive separation, and emotional detachment), and 1 for secure attachment. The scales include items (ranging from 6–16 in their original form) scored by raters using a 3-point format (0 = absent, 1 = present, and 2 = strongly present) and summed to produce a total score. Item response theory (IRT) analyses were conducted with data from 414 participants recruited from psychiatric outpatient, medical, and community settings to identify the most informative items from each scale. The IRT results allowed us to shorten the scales to 5-item versions that are more precise and easier to rate because of their brevity. In general, the effective range of measurement for the scales was 0 to +2 SDs for each of the attachment constructs; that is, from average to high levels of attachment problems. Evidence for convergent and discriminant validity of the scales was investigated by comparing them with the Experiences of Close Relationships–Revised (ECR–R) scale and the Kobak Attachment Q-sort. The best consensus among self-reports on the ECR–R, informant ratings on the ECR–R, and expert judgments on the Q-sort and the AAR emerged for anxious, ambivalent attachment. Given the good psychometric characteristics of the scale for secure attachment, however, this measure alone might provide a simple alternative to more elaborate procedures for some measurement purposes. Conversion tables are provided for the 7 scales to facilitate transformation from raw scores to IRT-calibrated (theta) scores.     

Acoustic masking disrupts time-dependent mechanisms of memory encoding in word-list recall

Recall of recently heard words is affected by the clarity of presentation: Even if all words are presented with sufficient clarity for successful recognition, those that are more difficult to hear are less likely to be recalled. Such a result demonstrates that memory processing depends on more than whether a word is simply “recognized” versus “not recognized.” More surprising is that, when a single item in a list of spoken words is acoustically masked, prior words that were heard with full clarity are also less likely to be recalled. To account for such a phenomenon, we developed the linking-by-active-maintenance model (LAMM). This computational model of perception and encoding predicts that these effects will be time dependent. Here we challenged our model by investigating whether and how the impact of acoustic masking on memory depends on presentation rate. We found that a slower presentation rate causes a more disruptive impact of stimulus degradation on prior, clearly heard words than does a fast rate. These results are unexpected according to prior theories of effortful listening, but we demonstrated that they can be accounted for by LAMM.     

The Role of Personality Factors in the Dynamics of Context and Psychological Well-Being

The purpose of this study was to determine personality factors that mediate between context and psychological well-being. A convenience sample of 514 mutlicultural participants from Potchefstroom (n=384) and Mafikeng (n=130) comprising mainly of black and white students was drawn. The participants completed measures on extraversion and agreeableness and psychological well-being in a cross-sectional survey. Context was defined in terms of differentials pertaining to race, socioeconomic differentials and infrastructural resources. Regression analyses indicated the viability of relationships among context, personality and psychological well-being. Structural equation models showed that both extraversion and agreeableness mediate the relationship between context and psychological well-being. Future research using longitudinal designs may study the importance of social context, personality factors and psychological well-being within and between groups.     

Psychometric Properties of Various Scales Measuring Psychological Well-Being in a South African Context: The FORT 1 Project

The aim of this study was to do a first phase screening of psychometric properties of various scales measuring facets of psychological well-being so as to address further questions in the FORT 1 project (FORT 1 = Clarifying the nature of psychological strengths). All scales (except one) were developed in a Western context, and measure facets of cognitive, affective, conative, social, and spiritual psychological well-being. As it could not be assumed that scales are valid in South African contexts, a broad screening of their psychometric properties was necessary before specific questions could be adressed. A convenience sample (N=514) including white (n=384) and black (n=130) students and adults from the North West Province and Gauteng areas completed all questionnaires. Psychometric properties of scales varied from acceptable to unacceptable for use in a specific subgroup.     

Individuals with congenital amusia imitate pitches more accurately in singing than in speaking: Implications for music and language processing

In this study, we investigated the impact of congenital amusia, a disorder of musical processing, on speech and song imitation in speakers of a tone language, Mandarin. A group of 13 Mandarin-speaking individuals with congenital amusia and 13 matched controls were recorded while imitating a set of speech and two sets of song stimuli with varying pitch and rhythm patterns. The results indicated that individuals with congenital amusia were worse than controls in both speech and song imitation, in terms of both pitch matching (absolute and relative) and rhythm matching (relative time and number of time errors). Like the controls, individuals with congenital amusia achieved better absolute and relative pitch matching and made fewer pitch interval and contour errors in song than in speech imitation. These findings point toward domain-general pitch (and time) production deficits in congenital amusia, suggesting the presence of shared pitch production mechanisms but distinct requirements for pitch-matching accuracy in language and music processing.     

Simulation of adatom clustering on a stepped surface

Study of the interaction and evolution behaviour of adatoms is fundamental to many surface phenomena. In the present paper, a continuum mechanics method, based on the force dipole concept, is presented to study the evolution of adatoms adsorbed on a smooth or stepped surface. The effects of elastic and van der Waals interactions are examined. It is found that the elastic interaction among adatoms usually serves as the main driving force for the clustering behaviour of adatoms and that the presence of surface defects, such as steps, may significantly influence the evolutionary arrangement of interacting adatoms.     

Phase-field model for ferromagnetic shape-memory alloys

A computational model is developed to predict the ferroelastic and ferromagnetic domain structures in ferromagnetic shape-memory alloys by combining the phase-field approach, micromagnetics and the microelasticity theory of Khachaturyan [Theory of Structural Transformations in Solid (Wiley, New York, 1983)]. As an example, the NiMnGa ferromagnetic shape-memory alloy is considered. Both the magnetic domain structures and martensite microstructures are studied. The emphasis is on the overall strain response and associated evolution of both magnetic domain structure and martensite microstructure under an applied magnetic field with different initial conditions. The results are compared with existing experiment measurements and observations.     

Enhanced visible-light absorption in heavily nitrogen-doped TiO2

Heavy nitrogen doping of TiO₂ thin films has been achieved by ion-beam-assisted deposition. The heavily doped films have a distorted anatase crystal structure and show an increase in visible-light absorption compared to films with only light nitrogen doping. The enhanced absorption is shown by a first-principles density-functional calculation to result from an electronic band-gap narrowing, in contrast to the appearance of isolated N 2p states above the valence-band maximum that occur with light nitrogen doping.     

Atomistic study of structural fluctuations during radiation-induced amorphization in the ordered intermetallic compound NiTi

We have carried out an atomistic study of electron-induced amorphization of an ordered intermetallic compound NiTi by means of in-situ high-resolution high-voltage electron microscopy observations and molecular dynamics simulations. Both theoretical and experimental results show that metastable nanometre-size atomic clusters form and disappear during irradiation, so that a spatiotemporal fluctuation under amorphization is induced. Mean-lifetime measurements of these clusters demonstrate that high-energy particle irradiation provides a useful tool to study dynamic fluctuations of the local atomic structure in the non-equilibrium open systems.