Interfaces: toward a new generation of systemic models in family research and practice

After reviewing Engel's bio-psycho-social proposal and Kandel's "principles for an integration between mind and brain," the author introduces a set of akin propositions that aim at integrating neurosciences, genetics, the mind, and the social world into a succinct set of systemic formulations focusing on interlevel interfaces, with profound implications for the training, practice, and research in the field of family processes and therapy.     

Working memory deficit in children with mathematical difficulties: a general or specific deficit?

This study examined whether children with mathematical difficulties (MDs) or comorbid mathematical and reading difficulties have a working memory deficit and whether the hypothesized working memory deficit includes the whole working memory system or only specific components. In the study, 31 10-year-olds with MDs and 37 10-year-olds with both mathematical and reading difficulties were compared with 47 age-matched and 50 younger controls (9-year-olds) on a number of working memory tasks. Compared with the age-matched controls, both groups of children with MDs performed worse on tasks tapping the central executive (e.g., visual matrix span) and the phonological loop (e.g., word span). More important, the MD group performed worse than the younger controls on the counting span task, whereas the group with comorbid mathematical and reading difficulties performed worse on the counting span task and the visual matrix span task. These findings provide support for the assumption that children with MDs have a working memory deficit. More specifically, children with MDs have a central executive deficit connected to concurrent processing and storage of numerical and visual information.     

Stereotype internalization and women’s math performance: The role of interference in working memory

It has long been argued that stigmatized individuals can ultimately internalize the stereotype alleging their inferiority. The present article investigated whether the internalization of the reputation of math inferiority that targets women can affect their math performance and whether this influence is caused by a disruption of working memory. A first study showed that stereotype endorsement had a significant impact on women’s statistic performance by lowering their self-evaluation of math ability even when controlling for prior achievement. A second study was designed to assess the possibility that the lower math performance displayed by women with low self-evaluation of math ability was due to interference in working memory. Using a dual task paradigm, this study showed that indeed women with low math self-evaluation displayed more errors and spent more time solving additions than women with high math self-evaluation, but mainly on difficult items of the dual task. The findings, which are congruent with an explanation in terms of a temporary disruption of working memory, are discussed.     

A model of working memory capacity in the radial-arm maze task

The radial arm maze is one of the most commonly used tests for assessing working memory in laboratory animals. However, to date, there exists no quantitative method of estimating working memory capacity from performance on this task. Here, we present a mathematical model of performance on the radial arm maze from which we can derive estimates of capacity. We derive explicit results for the two most commonly used measures of performance as functions of number of arms in the maze and memory capacity, assuming a uniform random search. We simulate random non-uniform search strategies. Comparing our model to previous experiments, we show that our model predicts a working memory capacity in the range of 3-9 at the level of performance observed in these experiments. This estimate is within the typical estimate of human working memory capacity. Performance of rats on large mazes (e.g. 48 arms) has been used as evidence that the working memory capacity of rats may be significantly larger than that of humans. We report that memory capacity in the range 3-9 is sufficient to explain the performance of rats in very large radial mazes. Furthermore, when we simulate non-uniform random search strategies observed in the experiments, the resulting estimates do not differ significantly from those assuming a uniform random search. We conclude that a list-based model of working memory with modest capacity is more powerful than previously expected.     

Cognition and hearing aids

The perceptual information transmitted from a damaged cochlea to the brain is more poorly specified than information from an intact cochlea and requires more processing in working memory before language content can be decoded. In addition to making sounds audible, current hearing aids include several technologies that are intended to facilitate language understanding for persons with hearing impairment in challenging listening situations. These include directional microphones, noise reduction, and fast-acting amplitude compression systems. However, the processed signal itself may challenge listening to the extent that with specific types of technology, and in certain listening situations, individual differences in cognitive processing resources may determine listening success. Here, current and developing digital hearing aid signal processing schemes are reviewed in the light of individual working memory (WM) differences. It is argued that signal processing designed to improve speech understanding may have both positive and negative consequences, and that these may depend on individual WM capacity.     

Cognition and aided speech recognition in noise: Specific role for cognitive factors following nine-week experience with adjusted compression settings in hearing aids

The working memory model for Ease of Language Understanding (ELU) proposes that language understanding under taxing conditions is related to explicit cognitive capacity. We refer to this as the mismatch hypothesis, since phonological representations based on the processing of speech under established conditions may not be accessed so readily when input conditions change and a match becomes problematic. Then, cognitive capacity requirements may differ from those used for processing speech hitherto. In the present study, we tested this hypothesis by investigating the relationship between aided speech recognition in noise and cognitive capacity in experienced hearing aid users when there was either a match or mismatch between processed speech input and established phonological representations. The settings in the existing digital hearing aids of the participants were adjusted to one of two different compression settings which processed the speech signal in qualitatively different ways ("fast" or "slow"). Testing took place after a 9-week period of experience with the new setting. Speech recognition was tested under different noise conditions and with match or mismatch (i.e. alternative compression setting) manipulations of the input signal. Individual cognitive capacity was measured using a reading span test and a letter monitoring test. Reading span, a reliable measure of explicit cognitive capacity, predicted speech recognition performance under mismatch conditions when processed input was incongruent with recently established phonological representations, due to the specific hearing aid setting. Cognitive measures were not main predictors of performance under match conditions. These findings are in line with the ELU model.     

Idealization and modeling

This paper examines the role of mathematical idealization in describing and explaining various features of the world. It examines two cases: first, briefly, the modeling of shock formation using the idealization of the continuum. Second, and in more detail, the breaking of droplets from the points of view of both analytic fluid mechanics and molecular dynamical simulations at the nano-level. It argues that the continuum idealizations are explanatorily ineliminable and that a full understanding of certain physical phenomena cannot be obtained through completely detailed, nonidealized representations.     

Computing the uncomputable; or,The discrete charm of second-order simulacra

We examine a case in which non-computable behavior in a model is revealed by computer simulation. This is possible due to differing notions of computability for sets in a continuous space. The argument originally given for the validity of the simulation involves a simpler simulation of the simulation, still further simulations thereof, and a universality conjecture. There are difficulties with that argument, but there are other, heuristic arguments supporting the qualitative results. It is urged, using this example, that absolute validation, while highly desirable, is overvalued. Simulations also provide valuable insights that we cannot yet (if ever) prove.     

On the language specificity of basic number processing: transcoding in a language with inversion and its relation to working memory capacity

Transcoding Arabic numbers from and into verbal number words is one of the most basic number processing tasks commonly used to index the verbal representation of numbers. The inversion property, which is an important feature of some number word systems (e.g., German einundzwanzig [one and twenty]), might represent a major difficulty in transcoding and a challenge to current transcoding models. The mastery of inversion, and of transcoding in general, might be related to nonnumerical factors such as working memory resources given that different elements and their sequence need to be memorized and manipulated. In this study, transcoding skills and different working memory components in Austrian (German-speaking) 7-year-olds were assessed. We observed that inversion poses a major problem in transcoding for German-speaking children. In addition, different components of working memory skills were differentially correlated with particular transcoding error types. We discuss how current transcoding models could account for these results and how they might need to be adapted to accommodate inversion properties and their relation to different working memory components.     

Visual versus phonological abilities in Spanish dyslexic boys and girls

Phonological and visual theories propose different primary deficits as part of the explanation for dyslexia. Both theories were put to test in a sample of Spanish dyslexic readers. Twenty-one dyslexic and 22 typically-developing children matched on chronological age were administered phonological discrimination and awareness tasks and coherent motion perception tasks. No differences were found between groups on the coherent motion tasks, whereas dyslexic readers were impaired relative to controls on phonological discrimination tasks. Gender differences followed the opposite pattern, with no differences on phonological tasks, and dyslexic girls performing significantly worse than dyslexic boys in coherent motion perception. These results point to the importance of phonological deficits related to speech perception in Spanish, and to possible gender differences in the neurobiological bases for dyslexia.