Creating a stem cell donor: a case study in reproductive genetics

During the nearly 10 years since its introduction, preimplantation genetic diagnosis (PGD) has been used predominantly to avoid giving birth to a child with identified genetic disease. Recently, PGD was used by a couple not only to test IVF-created embryos for genetic disease, but also to test for a nondisease trait related to immune compatibility with a child in the family in need of an hematropoetic stem cell transplant. This article describes the case, raises some ethical and policy issues, highlights gaps in U.S. policy, and finally makes some recommendations for addressing advancing genetic and reproductive technologies.     

Semantic priming of different affective categories

The authors investigated affective semantic priming using a lexical decision task with 4 affective categories of related word pairs: neutral, happy, fearful, and sad. Results demonstrated a striking and reliable effect of affective category on semantic priming. Neutral and happy prime-targets yielded significant semantic priming. Fearful pairs showed no or modest priming facilitation, and sad primes slowed reactions to sad targets. A further experiment established that affective primes do not have generalized facilitatory-inhibitory effects. The results are interpreted as showing that the associative mechanisms that support semantic priming for neutral words are also shared by happy valence words but not for negative valence words. This may reflect increased vigilance necessary in adverse contexts or suggest that the associative mechanisms that bind negative valence words are distinct.     

Self-directed affiliation and autonomy across acute and continuation phase cognitive therapy for recurrent depression

Using Benjamin's (2000) Structural Analysis of Social Behavior, we evaluated change in "self-directed" affiliation and autonomy and prediction of treatment response and relapse/recurrence among adult outpatients with recurrent major depressive disorder consenting to acute phase cognitive therapy (A-CT; Beck, Rush, Shaw, & Emery, 1979; N=156); A-CT responders randomized (N=84) to 8 months of continuation phase cognitive therapy (C-CT; Jarrett, 1989; Jarrett et al., 1998; Jarrett & Kraft, 1997) or assessment-only control; and C-CT and control patients entering a 16-month, assessment-only follow-up (N=74). Self-directed affiliation and autonomy increased after A-CT, and C-CT further increased affiliation and autonomy. Affiliation and autonomy did not predict A-CT response, but lower affiliation and higher autonomy pre-A-CT predicted relapse/recurrence post-A-CT. We discuss potential clinical implications of these results and present case examples to illustrate patterns of change.     

Transitive responding in hooded crows requires linearly ordered stimuli

Eight crows were taught to discriminate overlapping pairs of visual stimuli (A+ B-, B+ C-, C+ D-, and D+ E-). For 4 birds, the stimuli were colored cards with a circle of the same color on the reverse side whose diameter decreased from A to E (ordered feedback group). These circles were made available for comparison to potentially help the crows order the stimuli along a physical dimension. For the other 4 birds, the circles corresponding to the colored cards had the same diameter (constant feedback group). In later testing, a novel choice pair (BD) was presented. Reinforcement history involving stimuli B and D was controlled so that the reinforcement/nonreinforcement ratios for the latter would be greater than for the former. If, during the BD test, the crows chose between stimuli according to these reinforcement/nonreinforcement ratios, then they should prefer D; if they chose according to the diameter of the feedback stimuli, then they should prefer B. In the ordered feedback group, the crows strongly preferred B over D; in the constant feedback group, the crows' choice did not differ significantly from chance. These results, plus simulations using associative models, suggest that the orderability of the postchoice feedback stimuli is important for crows' transitive responding.     

Induction and categorization in young children: a similarity-based model

The authors present a similarity-based model of induction and categorization in young children (SINC). The model suggests that (a). linguistic labels contribute to the perceived similarity of compared entities and (b). categorization and induction are a function of similarity computed over perceptual information and linguistic labels. The model also predicts young children's similarity judgment, induction, and categorization performance under different stimuli and task conditions. Predictions of the model were tested and confirmed in 6 experiments, in which 4- to 5-year-olds performed similarity judgment, induction, and categorization tasks using artificial and real labels (Experiments 1-4) and recognition memory tasks (Experiments 5A and 5B). Results corroborate the similarity-based account of young children's induction and categorization, and they support both qualitative and quantitative predictions of the model.     

Changes in anabolic and catabolic activity among women taking part in an alternative labour market programme

Thirty-two female participants in a mobilising labour market programme offering temporary, alternative employment in Sweden were followed longitudinally for one year, including a six month post participation follow-up period. It can be hypothesised that an important aspect of the physiological effects of unemployment is a change in the balance between anabolic and catabolic activities in the body and that re-employment should lead to a shift towards anabolism. An earlier study of a smaller subset of the data, however, including both men and women, showed increased prolactin and decreased dehydroepiadrosterone sulphate (DHEA-s) levels, contrary to the initial hypothesis. In the present analysis, intended to elucidate these results, psychophysiological data were summarised in two indices, one connected with anabolism (made up of testosterone and DHEA-s) and one with catabolism (prolactin, γ-glutamyl transferase, aspartate amino transferase, α levuline amino transferase, and body mass index). In addition, self-rated anxiety, depression, hopelessness and personal control were analysed. The results indicate that the effect of ‘better’ activities within the programme was a temporary increase in anabolism, possibly indicating lower stress levels, and the effect of ‘worse’ activities, on the one hand, a temporary decrease in the catabolic index, probably reflecting repressed alcohol consumption, and, on the other hand, impaired anabolism. There was also a general but transient decrease in depressiveness measured by the Hospital Anxiety and Depression Scale. The results seem to imply that it is difficult to achieve lasting effects through a relatively short participation in a mobilising programme.     

Spatio-temporal working-memory and short-term object-location tasks use different memory mechanisms

Spatial short-term memory for objects' locations was investigated in a spatial relocation task. During maintenance, dynamic visual noise or spatial tapping were administered as visual or spatial secondary tasks, respectively. Because memory for location should tap the visual component of working memory, a visual but not a spatial secondary task should impair location memory. In fact, neither of the tasks impaired memory (Experiment 1), although the expected dissociation between visual and spatial components was clearly confirmed for a spatio-temporal main task (Corsi test) (Experiment 2). We then contrasted location memory for pictures of objects and of nonsense figures under visual interference. Real objects were relocated much better than nonsense figures, and visual noise was again ineffective (Experiment 3). When spatial tapping was combined with the same material (Experiment 3a), again no influence on memory for locations of objects was observed and only a small influence on remembering nonsense figures. We suggest that the Corsi and the relocation VSWM-tasks use different memory mechanisms. The configuration of objects is reconstructed from perceptual records in an episodic buffer, provided by the same structures that enable visual memory after longer intervals. Rehearsal is not necessary for the persistence of these traces. In contrast, in the Corsi task remembering, a temporal sequence across homogeneous locations needs spatio-temporal marking and therefore active rehearsal of the locations by shifting spatial attention. A spatially demanding secondary task during retention interrupts this rehearsal.     

Developmental dyslexia in different languages: language-specific or universal?

Most of the research on developmental dyslexia comes from English-speaking countries. However, there is accumulating evidence that learning to read English is harder than learning to read other European orthographies (Seymour, Aro, & Erskine, 2003). These findings therefore suggest the need to determine whether the main English findings concerning dyslexia can be generalized to other European orthographies, all of which have less irregular spelling-to-sound correspondences than English. To do this, we conducted a study with German- and English-speaking children (n=149) in which we investigated a number of theoretically important marker effects of the reading process. The results clearly show that the similarities between dyslexic readers using different orthographies are far bigger than their differences. That is, dyslexics in both countries exhibit a reading speed deficit, a nonword reading deficit that is greater than their word reading deficit, and an extremely slow and serial phonological decoding mechanism. These problems were of similar size across orthographies and persisted even with respect to younger readers that were at the same reading level. Both groups showed that they could process larger orthographic units. However, the use of this information to supplement grapheme-phoneme decoding was not fully efficient for the English dyslexics.