Perceptual learning in speech

This study demonstrates that listeners use lexical knowledge in perceptual learning of speech sounds. Dutch listeners first made lexical decisions on Dutch words and nonwords. The final fricative of 20 critical words had been replaced by an ambiguous sound, between [f] and [s]. One group of listeners heard ambiguous [f]-final words (e.g., [WItlo?], from witlof, chicory) and unambiguous [s]-final words (e.g., naaldbos, pine forest). Another group heard the reverse (e.g., ambiguous [na:ldbo?], unambiguous witlof). Listeners who had heard [?] in [f]-final words were subsequently more likely to categorize ambiguous sounds on an [f]-[s] continuum as [f] than those who heard [?] in [s]-final words. Control conditions ruled out alternative explanations based on selective adaptation and contrast. Lexical information can thus be used to train categorization of speech. This use of lexical information differs from the on-line lexical feedback embodied in interactive models of speech perception. In contrast to on-line feedback, lexical feedback for learning is of benefit to spoken word recognition (e.g., in adapting to a newly encountered dialect).     

Motion and edge sensitivity in perception of object unity

Although much evidence indicates that young infants perceive unitary objects by analyzing patterns of motion, infants' abilities to perceive object unity by analyzing Gestalt properties and by integrating distinct views of an object over time are in dispute. To address these controversies, four experiments investigated adults' and infants' perception of the unity of a center-occluded, moving rod with misaligned visible edges. Both alignment information and depth information affected adults' and infants' perception of object unity in similar ways, and infants perceived object unity by integrating information about object features over time. However, infants perceived a moving, misaligned, three-dimensional object as indeterminate in its connectedness, whereas adults perceived it as connected behind the occluder. These findings indicate that the effectiveness of common motion in specifying unified surfaces across an occluder is reduced by misalignment of edges. Alignment information enhances perception of object unity either by serving directly as information for unity or by optimizing the detectability of motion-carried information for unity. In addition, young infants are able to retain information about edge orientation over short intervals in determining connectedness via a process of spatiotemporal integration.     

Risk-taking behavior and adolescent suicide attempts

This study examined the overall rates of common risk-taking behaviors in a sample of 109 adolescents, aged 13 to 18 years, who made a suicide attempt, compared to a matched control sample of 218 adolescents in the community. No differences in either the total number of risk-taking behavior or the frequency of individual risk-taking behaviors were found. These findings suggest that suicide attempts in adolescents are not a function of risk-taking behavior.     

Psychometric properties of the Spanish Beck Depression Inventory-II in a medical sample

The authors examined the psychometric properties of the Spanish Beck Depression Inventory-II (BDI-II; A. T. Beck, R. A. Steer, & G. K. Brown, 1996) in a sample of individuals undergoing hemodialysis. They performed a confirmatory factor analysis of a previously reported 2-factor solution for the English BDI-II derived from a medical sample. Results indicate that the established model for the English-speaking medical sample provided adequate fit in the present sample. Spanish BDI-II scores were not significantly associated with age or gender in their sample, but they were significantly associated with disease severity. Bilingual participants completed the inventory in both Spanish and English, and their data revealed that BDI-II total scores were similar across language administration. The preliminary data suggest that the Spanish BDI-II can be reliably used in medical samples.     

Assessing worry in older adults: confirmatory factor analysis of the Penn State Worry Questionnaire and psychometric properties of an abbreviated model

The assessment of worry among older adults typically has involved measures designed with younger cohorts. Because of special concerns in assessing older adults, modifications to existing instruments may be necessary. Addressing equivocal factor analytic data on the Penn State Worry Questionnaire (PSWQ) among younger adults, the authors conducted confirmatory factor analyses to evaluate the generalizability of previous models to older adults with generalized anxiety disorder. Data fit poorly with established single- and two-factor models. The single-factor model was modified, resulting in the elimination of 8 items, strong fit indices, high internal consistency, adequate test-retest reliability, and good convergent and divergent validity. Further psychometric work is required to assess whether the revised model is a more parsimonious method to assess late-life anxiety.     

Knowledge and imagery of contractile mechanisms do not improve muscle strength

Improving performance in strength tasks requires modifications charateristic of motor skill learning, such as more efficacious motor-unit firing behavior. Because domain-specific knowledge is integral to learning and performing motor kills, the present purpose was to examine selected factors of strength-specific knowledge and effects they might have on acquiring strength. Following baseline testing for maximal strength on a knee-extension task, participants were matched by sex and strength and placed into control (n=8) and treatment (n=8) groups. Quadriceps muscle electromyographic data were also collected. The treatment group underwent two educational sessions detailing muscle physiology, neural control of muscle force, and imagery training using this knowledge. The control group underwent two educational sessions about health and fitness. Following the educational sessions the participants were retested for strength. Analysis indicated that the education and imagery treatment had no effect on strength, nor did electromyographic measures indicate that the treatment group benefitted from intervention. It was concluded that the knowledge was simply not relevant to knee extension-force production or that use of the knowledge involved a disadvantageous internal focus of attention away from relevant task demands.     

A common oscillator for perceptual rivalries?

Perceptual rivalry is an oscillation of conscious experience that takes place despite univarying. if ambiguous, sensory input. Much current interest is focused on the controversy over the neural site of binocular rivalry, a variety of perceptual rivalry for which a number of different cortical regions have been implicated. Debate continues over the relative role of higher levels of processing compared with primary visual cortex and the suggestion that different forms of rivalry involve different cortical areas. Here we show that the temporal pattern of disappearance and reappearance in motion-induced blindness (MIB) (Bonneh et al, 2001 Nature 411 798-801) is highly correlated with the pattern of oscillation reported during binocular rivalry in the same individual. This correlation holds over a wide range of inter-individual variation. Temporal similarity in the two phenomena was strikingly confirmed by the effects of the hallucinogen LSD, which produced the same, extraordinary, pattern of increased rhythmicity in both kinds of perceptual oscillation. Furthermore. MIB demonstrates the two properties previously considered characteristic of binocular rivalry. Namely the distribution of dominance periods can be approximated by a gamma distribution and, in line with Levelt's second proposition of binocular rivalry, predominance of one perceptual phase can be increased through a reduction in the predominance time of the opposing phase. We conclude that (i) MIB is a form of perceptual rivalry, and (ii) there may be a common oscillator responsible for timing aspects of all forms of perceptual rivalry.     

An information-processing model of the BOLD response in symbol manipulation tasks

Two imaging experiments were performed—one involving an algebraic transformation task studied by Anderson, Reder, and Lebiere (1996) and the other an abstraction symbol manipulation task studied by Blessing and Anderson (1996). ACT-R models exist that predict the latency patterns in these tasks. These models require activity in an imaginal buffer to represent changes to the problem representation, in a retrieval buffer to hold information from declarative memory, and in a manual buffer to hold information about motor behavior. A general theory is described about how to map activity in these buffers onto the fMRI blood oxygen level dependent (BOLD) response. This theory claims that the BOLD response is integrated over the duration that a buffer is active and can be used to predict the observed BOLD function. Activity in the imaginal buffer is shown to predict the BOLD response in a left posterior parietal region; activity in the retrieval buffer is shown to predict the BOLD response in a left prefrontal region; and activity in the manual buffer is shown to predict activity in a motor region. More generally, this article shows how to map a large class of information-processing theories (not just ACT-R) onto the BOLD response and provides a precise interpretation of the cognitive significance of the BOLD response.     

Children with lesbian parents: a community study

Existing research on children with lesbian parents is limited by reliance on volunteer or convenience samples. The present study examined the quality of parent-child relationships and the socioemotional and gender development of a community sample of 7-year-old children with lesbian parents. Families were recruited through the Avon Longitudinal Study of Parents and Children, a geographic population study of 14,000 mothers and their children. Thirty-nine lesbian-mother families, 74 two-parent heterosexual families, and 60 families headed by single heterosexual mothers were compared on standardized interview and questionnaire measures administered to mothers, co-mothers/fathers, children, and teachers. Findings are in line with those of earlier investigations showing positive mother-child relationships and well-adjusted children.