A strict test of the phonological loop hypothesis with Libyan data

In Arabic, there are two ways, differing in length, of pronouncing each digit. This feature of word pairs that are conceptually identical but of different length allows for a stricter test of the phonological loop hypothesis than has been reported previously. Libyan schoolchildren, both boys and girls, of two grades took part in a quasi-experimental study in which shorter and longer digits and shorter and longer words were presented in recall and pronunciation tasks. The results confirmed the validity of the phonological loop model in that memory span was longer for shorter stimuli. Analysis of the data with structural equation modeling showed that only 17% of the individual-level variation in memory span could be explained by pronunciation speed. In an analysis of covariance, it was determined that pronunciation speed could account for a substantial proportion of the variation found across age (8-year-olds vs. 10-year-olds), stimulus modality (digits vs. words), and stimulus length (short vs. long), but not for gender differences.     

Educating Genetic Counselors in Australia: Developing an International Perspective

The demand for genetic counseling services is increasing worldwide. This paper highlights the Australian experience of genetic counselor education and the history of the profession. The relevance of local factors, including the healthcare system, the education system and the small population in the evolution of the 1-year training programs are considered as an alternative model for emerging programs. The development of the education and training processes compared to that of other countries namely the United States of America (USA), the United Kingdom (UK) and Canada is discussed. The importance of international collaborations between the programs, to facilitate academic discussion and possible curriculum innovations, and to maintain professional understanding between genetic counselors is emphasized. Core genetic counseling competencies have been published for the UK and USA and an Australian set is proposed. In conclusion future directions are considered, including international issues around genetic counseling certification, reciprocity, and the potential for an Australian role in training genetic counselors in South East Asia.     

The influence of accuracy as a function of leader's bias: the role of trustworthiness in the psychology of procedural justice

The present research examined the combined effect of accuracy of procedures and leader's bias on fairness judgments and the experience of positive emotions. The results of two studies showed that the strongest positive effects on both types of reactions were found when procedures were accurate and the leader was unbiased. In addition, accuracy of procedures only revealed an impact when the leader was perceived as unbiased rather than biased. Moreover, this interactive effect was found to be mediated, at least partly, by perceptions of trustworthiness. These findings show that more research is needed on examining different types of procedural fairness, both as single and combined predictors of people's reactions.     

Contributions of metaknowledge to retrieval of natural categories in semantic memory

Retrieving the answer to a general knowledge question has been shown to involve two metacognitive processes--a feeling-of-knowing that initiates the search of long-term memory and a willingness to continue searching until an answer can be confidently stated. To extend this model, college students were asked to retrieve as many members of 2 natural categories as they could in 1 min. Examination of the points at which they switched categories revealed that they searched longer in categories of higher potency, and they switched earlier when the other category was of higher potency. They also searched the first category longer when they were allowed to switch only once during a trial rather than as often as they wished. It was concluded that feeling-of-knowing maintained search of a category and also contributed to the willingness to continue searching, and the constraint on switching impacted the willingness to continue.     

Spatial Simon effects with nonspatial responses

Recent studies have shown that spatial Simon effects can be modulated by short-term associations that are set up as a result of task instructions. I examined whether spatial Simon effects can also be produced by short-term associations even when the responses are unrelated to spatial position. Participants were to say “cale” or “cole” on the basis of the direction of arrows (i.e., left or right), the meaning of words (i.e.,left orright), and the color of squares presented left or right of the screen center. Responses to squares were faster when the correct response was associated with the same position as the irrelevant position of the square (e.g., say “cale” to a square on the left when “cale” was assigned to the wordleft and the left arrow). This new type of stimulus-response compatibility effect provides the first evidence for short-term associations that involve mode-independent representations.     

Coordinate high-frequency pattern of stimulation and calcium levels control the induction of LTP in striatal cholinergic interneurons

Current evidence appoints a central role to cholinergic interneurons in modulating striatal function. Recently, a long-term potentiation (LTP) of synaptic transmission has been reported to occur in these neurons. The relationship between the pattern of cortico/thalamostriatal fibers stimulation, the consequent changes in the intracellular calcium concentration ([Ca2+]i), and the induction of synaptic plasticity was investigated in striatal cholinergic interneurons from a rat corticostriatal slice preparation by means of combined electrophysiological intracellular recordings and microfluorometric techniques. Different protocols of stimulation were considered, varying both the frequency and the duration of the train of stimuli. High-frequency stimulation (HFS) (three trains at 100 Hz for 3 sec, 20-sec interval) induced a rise in [Ca2+]i, exceeding by fivefold the resting level, and caused a LTP of synaptic transmission. Tetanic stimulation delivered at lower frequencies (5-30 Hz) failed to induce long-term changes of synaptic efficacy. The observed elevation in [Ca2+]i during HFS was primarily mediated by L-type high-voltage activated (HVA)-Ca2+ channels, as it was fully prevented by nifedipine. Conversely, blockade of NMDA and AMPA glutamate receptor did not affect either LTP or the magnitude of the [Ca2+]i rise. Interestingly, the pharmacological analysis of the post-tetanic depolarizing postsynaptic potential (DPSP) revealed that LTP was attributable, to a large extent, to the potentiation of the GABA(A)-mediated component. In conclusion, the expression of LTP in striatal cholinergic interneurons is a selective response to a precise stimulation pattern of induction requiring a critical rise in [Ca2+]i.     

Imposing structure on a Corsi-type task: evidence for hierarchical organisation based on spatial proximity in serial-spatial memory

Structure was imposed on a tapping task by requiring participants to reproduce sequences of responses to icons organised in spatial clusters. A first experiment featured sequences either segregated or not segregated by clusters. Accuracy was higher for sequences segregated by clusters. Moreover, inter-response times were longer at cluster boundaries than within cluster boundaries. To rule out possible confounding effects of movement length, this temporal pattern was replicated in a second experiment requiring a single response indicating the next sequential step, following the presentation of a portion of a previously practised sequence. These results suggest that sequence reproduction can be sustained by a hierarchical representation based on spatial proximity and provide a first indication of the role of spatial structure in serial-spatial memory.     

The Role of Cognitive Deficits in the Development of Eating Disorders

Eating disorders (ED), including anorexia and bulimia nervosa, are chronic illnesses with periods of symptom exacerbation and remission. Because symptoms are usually present from 6 to 24 months before a diagnosis is made, aetiological agents are believed to be active well before symptoms appear. It is proposed that neuropsychological deficits in various cognitive domains preexist and underlie the aetiology of ED. This paper provides a comprehensive review of the literature relevant to neuropsychological deficits in ED patients and explores the relationship between cognitive deficits, psychosocial development, and the development of ED. Although the role of neuropsychological deficits in the evolution of ED requires further research, the proposed association has significant implications for clinical practice.     

On the role of stimulus-response and stimulus-stimulus compatibility in the Stroop effect

Stroop effects might be due to differences in stimulus-response compatibility (SRC) and/or to differences in stimulus-stimulus compatibility (SSC). Recent evidence for the role of SSC is inconclusive, because there were no controls for effects of SRC that are based on short-term associations between stimuli and responses (i.e., associations set up as the result of task instructions). In two experiments, SRC effects were controlled for. Regardless of whether the irrelevant and the relevant stimulus features were separated (Experiment 1) or integrated in one stimulus (Experiment 2), the results revealed an effect of SSC and an effect of SRC that was based on short-term associations. The results thus confirm that both processes at the level of encoding and processes at the level of response selection contribute to the Stroop effect.     

Roles of working memory capacity and long-term working memory skill in complex task performance

In the present research, we examined the relative roles of domain-general and domain-specific individual difference characteristics in complex cognitive task performance. Specifically, we examined the impact both of working memory (WM) capacity and of acquired skills used to encode presented information in an accessible form in long-term working memory (LTWM) on performance in a complex aviation task environment. Measures of WM capacity and LTWM skill served as performance predictors. A criterion measure of task performance was related to the predictor measures. The results indicated that an increase in LTWM skill decreases the role of WM capacity as the determinant of complex task performance, although both measures are important performance predictors. We discuss how the two distinct WM constructs coexist and interact to support complex task performance.