A cross‐syndrome study of the differential effects of sleep on declarative memory consolidation in children with neurodevelopmental disorders

Sleep plays an active role in memory consolidation. Because children with Down syndrome (DS) and Williams syndrome (WS) experience significant problems with sleep and also with learning, we predicted that sleep‐dependent memory consolidation would be impaired in these children when compared to typically developing (TD) children. This is the first study to provide a cross‐syndrome comparison of sleep‐dependent learning in school‐aged children. Children with DS (n = 20) and WS (n = 22) and TD children (n = 33) were trained on the novel Animal Names task where they were taught pseudo‐words as the personal names of ten farm and domestic animals, e.g. Basco the cat, with the aid of animal picture flashcards. They were retested following counterbalanced retention intervals of wake and sleep. Overall, TD children remembered significantly more words than both the DS and WS groups. In addition, their performance improved following night‐time sleep, whereas performance over the wake retention interval remained stable, indicating an active role of sleep for memory consolidation. Task performance of children with DS did not significantly change following wake or sleep periods. However, children with DS who were initially trained in the morning continued to improve on the task at the following retests, so that performance on the final test was greater for children who had initially trained in the morning than those who trained in the evening. Children with WS improved on the task between training and the first retest, regardless of whether sleep or wake occurred during the retention interval. This suggests time‐dependent rather than sleep‐dependent learning in children with WS, or tiredness at the end of the first session and better performance once refreshed at the start of the second session, irrespective of the time of day. Contrary to expectations, sleep‐dependent learning was not related to baseline level of performance. The findings have significant implications for educational strategies, and suggest that children with DS should be taught more important or difficult information in the morning when they are better able to learn, whilst children with WS should be allowed a time delay between learning phases to allow for time‐dependent memory consolidation, and frequent breaks from learning so that they are refreshed and able to perform at their best.     

Changes in the relationship between movement velocity and movement distance in primary focal hand dystonia

The authors examined the relationship between movement velocity and distance and the associated muscle activation patterns in 18 individuals with focal hand dystonia (FHD) compared with a control group of 18 individuals with no known neuromuscular condition. Participants performed targeted voluntary wrist and elbow flexion movements as fast as possible across 5 movement distances. Individuals with FHD were slower than controls across all distances, and this difference was accentuated for longer movements. Muscle activation patterns were triphasic in the majority of individuals with FHD, and muscle activation scaled with distance in a similar manner to controls. Cocontraction did not explain movement slowing in individuals with dystonia, but there was a trend toward underactivation of the 1st agonist burst in the dystonic group. The authors concluded that slowness is a consistent feature of voluntary movement in FHD and is present even in the absence of dystonic posturing. Underactivation of the 1st agonist burst appears to be the most likely reason to explain slowing.     

When attitudes do not fit: discordance of acculturation attitudes as an antecedent of intergroup threat

Recent research has shown that the perspectives of both minorities and majorities should be taken into account to reach a deeper understanding of the acculturation process and its consequences for intergroup relations. The authors report two experiments that investigated the impact of discordant acculturation attitudes on perceived threat. In Study 1 (N=183), Germans were asked for their attitudes toward Turks and Italians. Different levels of concordance of acculturation attitudes were induced by presenting participants with newspaper articles describing the acculturation attitude of the respective out-group and perceived threat was measured. In Study 2 (N=100), two fictitious immigrant groups were used as target groups. Results in both studies showed that discordance of acculturation attitudes leads to higher perceptions of intergroup threat than concordance of acculturation attitudes. Furthermore, both studies supported the assumption that a similar out-group is perceived as less threatening than a dissimilar out-group.     

Effects of acceptance-oriented versus evaluative emotional processing on heart rate recovery and habituation

The effects of emotional processing on stress response trajectories may depend on the nature of processing, as evaluative rumination about emotions can prolong distress. In contrast, observing negative emotions in an accepting manner may promote efficient recovery from stressful situations. The present study examined the effect of acceptance-oriented versus evaluative emotional processing on cardiovascular habituation and recovery. Across two experimental sessions, 81 participants were randomly assigned to write about an ongoing stressful experience while either (1) evaluating the appropriateness of their emotional response (EVAL), (2) attending to their emotions in an accepting way (ACC), or (3) describing the objective details of the experience (CTL). Heart rate was assessed continuously throughout baseline, writing, and recovery. Results suggest that writing about emotions in an evaluative way leads to less efficient heart rate habituation and recovery than processing emotions in an accepting manner. These findings highlight a potential mechanism of mindfulness- and acceptance-based interventions' effects on health outcomes and further suggest that habitually evaluating the appropriateness of one's emotional responses rather than accepting them as they unfold may have consequences for cardiovascular health.     

The processing of interlexical homographs in translation recognition and lexical decision: Support for non-selective access to bilingual memory

In three experiments we looked at the processing of interlexical homographs by Dutch-English bilinguals. In Experiment 1 we employed the translation recognition task, a task that forces the participants to activate both language systems simultaneously. In this task the processing of interlexical homographs was inhibited substantially compared to the processing of matched control words, especially when the homograph reading to be selected was the less frequent of the homograph's two readings. In Experiments 2 and 3 we used the lexical decision task: In one condition we asked the participants to categorize letter strings as words or nonwords in Dutch; in a second condition we asked them to do so in English. The makeup of the stimulus set in Experiment 2 permitted the participants to ignore the instructions and to instantiate the task in a language-neutral form-that is, to categorize the letter strings as words in either Dutch or English. Under these circumstances a small, frequency-dependent inhibitory effect for homographs was obtained, but only in condition Dutch. In Experiment 3 the participants were forced in a language-specific processing mode by the inclusion of "nonwords" that were in fact words in the non-target language. Large frequency-dependent inhibitory effects for homographs were now obtained in both language conditions. The combined results are interpreted as support for the view that bilingual lexical access is non-selective.     

The emergence of interest in the ethics of psychological research with humans

We describe the growth of interest in the ethics of research with human participants based on articles abstracted in Psychological Abstracts and PsycLIT. Interest was low and variable until 1974, after which there was a marked increase in the number of articles published. We explain this emergence of ethical interest in terms of the social climate of concern for human rights in the 1960s and 1970s, the 1973 revision of the American Psychological Association's ethical principles, and the development of federal regulation of research with human participants.     

Maya Angelou's Inaugural Poem

Maya Angelou's performance of her poem On the Pulse of Morning at the inauguration of William Jefferson Clinton as 42nd President of the United States on January 20, 1993, was compared with other poetry and prose performances. Measurements of her pause frequency, pause location, pause duration, phrase length, speech rate, articulation rate, and percentage of pause time all uniquely characterized her performance. Printed versions of Angelou's inaugural poem were also analyzed. Inconsistencies in spelling, punctuation, spacing, and line and stanza breaks, along with additions, omissions, and sequence changes of words and phrases, were found. The poem performed possesses a richness unpredictable from either the extant literature on poetry readings or from Angelou's own printed pages.     

The over‐pruning hypothesis of autism

This article outlines the over‐pruning hypothesis of autism. The hypothesis originates in a neurocomputational model of the regressive sub‐type (Thomas, Knowland & Karmiloff‐Smith, 2011a, 2011b). Here we develop a more general version of the over‐pruning hypothesis to address heterogeneity in the timing of manifestation of ASD, including new computer simulations which reconcile the different observed developmental trajectories (early onset, late onset, regression) via a single underlying atypical mechanism; and which show how unaffected siblings of individuals with ASD may differ from controls either by inheriting a milder version of the pathological mechanism or by co‐inheriting the risk factors without the pathological mechanism. The proposed atypical mechanism involves overly aggressive synaptic pruning in infancy and early childhood, an exaggeration of a normal phase of brain development. We show how the hypothesis generates novel predictions that differ from existing theories of ASD including that (1) the first few months of development in ASD will be indistinguishable from typical, and (2) the earliest atypicalities in ASD will be sensory and motor rather than social. Both predictions gain cautious support from emerging longitudinal studies of infants at‐risk of ASD. We review evidence consistent with the over‐pruning hypothesis, its relation to other current theories (including C. Frith's under‐pruning proposal; C. Frith, 2003, 2004), as well as inconsistent data and current limitations. The hypothesis situates causal accounts of ASD within a framework of protective and risk factors (Newschaffer et al., 2012); clarifies different versions of the broader autism phenotype (i.e. the implication of observed similarities between individuals with autism and their family members); and integrates data from multiple disciplines, including behavioural studies, neuroscience studies, genetics, and intervention studies.