Learnability of embedded syntactic structures depends on prosodic cues

The ability to process center-embedded structures has been claimed to represent a core function of the language faculty. Recently, several studies have investigated the learning of center-embedded dependencies in artificial grammar settings. Yet some of the results seem to question the learnability of these structures in artificial grammar tasks. Here, we tested under which exposure conditions learning of center-embedded structures in an artificial grammar is possible. We used naturally spoken syllable sequences and varied the presence of prosodic cues. The results suggest that mere distributional information does not suffice for successful learning. Prosodic cues marking the boundaries of the major relevant units, however, can lead to learning success. Thus, our data are consistent with the hypothesis that center-embedded syntactic structures can be learned in artificial grammar tasks if language-like acoustic cues are provided.     

Should all stationary objects move when hit? Developments in infants’ causal and statistical expectations about collision events

Four experiments examined 8- and 9-month-old infants’ expectations about collision events. The infants saw test events in which a small cylinder rolled down a ramp and hit one of several different boxes. These boxes varied in width and height and always remained stationary when hit. The results revealed two separate developments. The first involved infants’ knowledge of the variables relevant to collision events. At 8 months, the infants expected all of the boxes to move when hit, regardless of their sizes; at 9 months, the infants began to take into account the size of the boxes to predict whether they should move when hit. The second development concerned infants’ ability to generate explanations for outcomes that violated their collision knowledge. At both ages, upon observing that a box with a salient vertical dimension did not move when hit, the infants apparently concluded that the box must be one of those objects we term pillars—vertical objects that are attached at one or both ends to adjacent surfaces. At 8 months, the infants considered any vertical box as a potential pillar; at 9 months, the infants considered only boxes that were both vertical and narrow as potential pillars. The development of infants’ knowledge about collision events is thus one that is complex and protracted and weaves together many separate developments.     

Grammatical pattern learning by human infants and cotton-top tamarin monkeys

There is a surprising degree of overlapping structure evident across the languages of the world. One factor leading to cross-linguistic similarities may be constraints on human learning abilities. Linguistic structures that are easier for infants to learn should predominate in human languages. If correct, then (a) human infants should more readily acquire structures that are consistent with the form of natural language, whereas (b) non-human primates' patterns of learning should be less tightly linked to the structure of human languages. Prior experiments have not directly compared laboratory-based learning of grammatical structures by human infants and non-human primates, especially under comparable testing conditions and with similar materials. Five experiments with 12-month-old human infants and adult cotton-top tamarin monkeys addressed these predictions, employing comparable methods (familiarization-discrimination) and materials. Infants rapidly acquired complex grammatical structures by using statistically predictive patterns, failing to learn structures that lacked such patterns. In contrast, the tamarins only exploited predictive patterns when learning relatively simple grammatical structures. Infant learning abilities may serve both to facilitate natural language acquisition and to impose constraints on the structure of human languages.     

Dynamic Structure in Diagnostic Structured Interviewing: A Comparative Test of Accuracy and Efficiency

The incorporation of Bayesian logic into diagnostic interviewing may assist with empirically based diagnostic assessment strategies in practice settings, balancing cost effectiveness, administration demands, and accuracy, yet few demonstrations of such a system have been undertaken in the context of mental health diagnosis. The present study represented an initial feasibility demonstration of whether a simplified Bayesian approach offered comparative advantages in interview accuracy and efficiency against a standard assessment procedure. Two different diagnostic algorithms were compared targeting three selected diagnoses: generalized anxiety disorder (GAD), major depressive disorder (MDD), and social phobia (SP). The first algorithm was from a standard semi-structured diagnostic interview, and the second was from a dynamic system using diagnostic base rate information to select interview content. The dynamic algorithm reduced administration time and uniformly matched or improved accuracy over standard procedures. Preparation of this article was supported in part by National Institute of Mental Health Grant R03 MH60134, an award from the University of Hawai‘i Research Council, and awards from the Hawaii Departments of Health and Education to the first author.     

Utilisation des intervalles de confiance au lieu des tests de signification : aspects épistémologiques et pratiques

The use of confidence intervals instead of significance tests is strongly recommended by the fifth edition of the manual of the American Psychological Association (2001). This possibility as well as other improvements in statistical practice are discussed in the framework of the major theoretical options subtending statistical inference and the way they have been applied in psychology for about 50 years. First, the suggestion of a complete ban on statistical testing is examined and rejected. Next, a procedure consisting in measuring the fit of two competing models based on the likelihood ratio is judged interesting and commendable. Finally, the superiority of an approach based on confidence intervals instead of significance tests is assessed and illustrated by its application to an experimental study aiming to demonstrate the absence instead of the presence of an effect of the independent variable.     

Paul Meehl and the evolution of statistical methods in psychology

In his landmark 1978 paper, Paul Meehl delineated, with remarkable clarity, some fundamental challenges facing soft psychology as it attempts to test theory with data. In the quarter century that followed, Meehl’s views stimulated much debate and progress, while continually evolving to keep pace with that progress. This paper pays homage to Meehl’s prescience, and traces the impact of his ideas on the recent shift of emphasis away from hypothesis testing and toward confidence interval estimates of effect size.     

Two-dimensional Langevin approach to the human stabilogram

Two-dimensional Langevin equation is considered as a model of the center of pressure (COP) random walk at quiet standing condition. The matrix of the mean square displacement describes quantitatively the COP random walk. Twenty-six young subjects were included in the study. Elements of the matrix of the mean square displacement derived from experimental data are well approximated by theoretical expressions derived from the Langevin equation, in the short-term regime. We have studied statistical properties of the COP displacements. Non-Gaussian behaviour of the displacements is indicated by the characteristic functions. New coordinate system constituted and utilised by the postural control system (PCS) was found for every subject. This new coordinate system is turned with respect to the system defined by the anatomy of the body. In this new coordinate system the matrix of the mean square displacement takes the form close to diagonal. The status of PCS in this new coordinate system can be quantified by the elements of the diffusion matrix, which are the measure of the stochastic activity of that system, rotation angle of new coordinate system and the friction coefficient. We have applied this analysis to examine how the visual inputs affect the PCS. We have found that the stochastic activity of the PCS increases after exclusion of the visual inputs. We have also shown that the visual system does not affect the friction coefficient. Furthermore, we have found that orientation of the new coordinate system chosen by PCS at included visual inputs differs from the orientation at excluded visual inputs.