Linking working memory and long-term memory: a computational model of the learning of new words

The nonword repetition (NWR) test has been shown to be a good predictor of children's vocabulary size. NWR performance has been explained using phonological working memory, which is seen as a critical component in the learning of new words. However, no detailed specification of the link between phonological working memory and long-term memory (LTM) has been proposed. In this paper, we present a computational model of children's vocabulary acquisition (EPAM-VOC) that specifies how phonological working memory and LTM interact. The model learns phoneme sequences, which are stored in LTM and mediate how much information can be held in working memory. The model's behaviour is compared with that of children in a new study of NWR, conducted in order to ensure the same nonword stimuli and methodology across ages. EPAM-VOC shows a pattern of results similar to that of children: performance is better for shorter nonwords and for wordlike nonwords, and performance improves with age. EPAM-VOC also simulates the superior performance for single consonant nonwords over clustered consonant nonwords found in previous NWR studies. EPAM-VOC provides a simple and elegant computational account of some of the key processes involved in the learning of new words: it specifies how phonological working memory and LTM interact; makes testable predictions; and suggests that developmental changes in NWR performance may reflect differences in the amount of information that has been encoded in LTM rather than developmental changes in working memory capacity.     

Is perceptual space inherently non-Euclidean?

It is often assumed that the space we perceive is Euclidean, although this idea has been challenged by many authors. Here we show that if spatial cues are combined as described by Maximum Likelihood Estimation, Bayesian, or equivalent models, as appears to be the case, then Euclidean geometry cannot describe our perceptual experience. Rather, our perceptual spatial structure would be better described as belonging to an arbitrarily curved Riemannian space.     

Impact of Traumatic Life Events in a Community Sample of Toddlers

Toddlers may be at particularly high risk for a number of psychiatric, developmental and neurobiological consequences in the aftermath of trauma. The social and emotional impact of potentially traumatic life events experienced between 6 and 36-months of age was assessed in an epidemiological birth cohort of 18- to 36-month-olds from the Greater New Haven Area. Event-exposed toddlers evidenced greater symptom severity on the ITSEA Internalizing, Externalizing, Dysregulation, Atypical and Maladaptive scales, as well on the CBCL Internalizing and Externalizing scales than those not exposed. Approximately one-fifth of event-exposed toddlers were reported by their parents to have experienced a dramatic change in functioning following the event, and were described as experiencing higher levels of symptoms consistent with Post-Traumatic Stress Disorder (PTSD), namely re-experiencing and arousal, than exposed toddlers whose parents did not report a change in their functioning. Implications for clinicians and child care providers working with toddlers and their parents are discussed.     

Implementing the Netherlands Code of Conduct for Scientific Practice—A Case Study

Widespread enthusiasm for establishing scientific codes of conduct notwithstanding, the utility of such codes in influencing scientific practice is not self-evident. It largely depends on the implementation phase following their establishment—a phase which often receives little attention. The aim of this paper is to provide recommendations for guiding effective implementation through an assessment of one particular code of conduct in one particular institute. Based on a series of interviews held with researchers at the Department of Biotechnology of Delft University of Technology, this paper evaluates how the Netherlands Code of Conduct for Scientific Practice is received by those it is supposed to govern. While respondents agreed that discussion of the guiding principles of scientific conduct is called for, they did not consider the code as such to be a useful instrument. As a tool for the individual scientific practitioner, the code leaves a number of important questions unanswered in relation to visibility, enforcement, integration with daily practice and the distribution of responsibility. Recommendations are provided on the basis of these questions. There is more at stake than merely holding scientific practitioners to a proper exercise of their duties; implementation of scientific society codes of conduct also concerns the further motives and value commitments that gave rise to their establishment in the first place.

Syntactic Representations Are Both Abstract and Semantically Constrained: Evidence From Children’s and Adults’ Comprehension and Production/Priming of the English Passive

All accounts of language acquisition agree that, by around age 4, children’s knowledge of grammatical constructions is abstract, rather than tied solely to individual lexical items. The aim of the present research was to investigate, focusing on the passive, whether children’s and adults’ performance is additionally semantically constrained, varying according to the distance between the semantics of the verb and those of the construction. In a forced-choice pointing study (Experiment 1), both 4- to 6-year olds (N = 60) and adults (N = 60) showed support for the prediction of this semantic construction prototype account of an interaction such that the observed disadvantage for passives as compared to actives (i.e., fewer correct points/longer reaction time) was greater for experiencer-theme verbs than for agent-patient and theme-experiencer verbs (e.g., Bob was seen/hit/frightened by Wendy). Similarly, in a production/priming study (Experiment 2), both 4- to 6-year olds (N = 60) and adults (N = 60) produced fewer passives for experiencer-theme verbs than for agent-patient/theme-experiencer verbs. We conclude that these findings are difficult to explain under accounts based on the notion of A(rgument) movement or of a monostratal, semantics-free, level of syntax, and instead necessitate some form of semantic construction prototype account.     

Researching self-help/mutual aid groups and organizations: Many roads, one journey

Self-help and mutual help groups are defined and the status of the literature described and reviewed. Self-help groups are different from peer and nonprofessional services under the supervision of professionals. Controlled studies of mutual help groups may be neither possible nor desirable as the method of choice by which to understand the phenomena of interest. Other approaches to research, including worldly evaluations, and ways of construing self-help organizations, that is, as normative communities and political action organizations rather than as psychological treatments, are discussed, and suggestions for future research are presented.