Socioeconomic background,nonverbal IQ and school absence affects the development of vocabulary and reading comprehension in children living in severe poverty

Few studies have examined how socioeconomic status (SES) affects two essential parts of human development, namely vocabulary and reading comprehension, in children facing severe poverty. The Roma population is the largest minority group in Europe, the majority of whom live in severe poverty. This study compared the development of 322 Roma children with the development of 178 non‐Roma children, between the ages of 7 and 10 years, living in Romania. The Roma children had poorer initial vocabulary and reading comprehension skills as well as slower growth rates for both compared to the non‐Roma children. Importantly, SES had a direct influence on growth in both reading comprehension and vocabulary. The effect of SES was partly mediated by school absence and nonverbal IQ. This is a powerful finding since it suggests that poverty may have detrimental effects not only on reading but also on the development of verbal abilities.     

Effector dynamics of rhythmic wrist activity and its implications for (modeling) bimanual coordination

To examine the role of the effector dynamics of the wrist in the production of rhythmic motor activity, we estimated the phase shifts between the EMG and the task-related output for a rhythmic isometric torque production task and an oscillatory movement, and found a substantial difference (45-52 degrees) between the two. For both tasks, the relation between EMG and task-related output (torque or displacement) was adequately reproduced with a physiologically motivated musculoskeletal model. The model simulations demonstrated the importance of the contribution of passive structures to the overall dynamics and provided an account for the observed phase shifts in the dynamic task. Additional simulations of the musculoskeletal model with added load suggested that particular changes in the phase relation between EMG and movement may follow largely from the intrinsic muscle dynamics, rather than being the result of adaptations in the neural control of joint stiffness. The implications of these results are discussed in relation to (models of) interlimb coordination in rhythmic tasks.     

Neurocognitive mechanisms underlying the experience of flow

Recent theoretical and empirical work in cognitive science and neuroscience is brought into contact with the concept of the flow experience. After a brief exposition of brain function, the explicit-implicit distinction is applied to the effortless information processing that is so characteristic of the flow state. The explicit system is associated with the higher cognitive functions of the frontal lobe and medial temporal lobe structures and has evolved to increase cognitive flexibility. In contrast, the implicit system is associated with the skill-based knowledge supported primarily by the basal ganglia and has the advantage of being more efficient. From the analysis of this flexibility/efficiency trade-off emerges a thesis that identifies the flow state as a period during which a highly practiced skill that is represented in the implicit system's knowledge base is implemented without interference from the explicit system. It is proposed that a necessary prerequisite to the experience of flow is a state of transient hypofrontality that enables the temporary suppression of the analytical and meta-conscious capacities of the explicit system. Examining sensory-motor integration skills that seem to typify flow such as athletic performance, writing, and free-jazz improvisation, the new framework clarifies how this concept relates to creativity and opens new avenues of research.     

The facilitated processing of threatening faces: an ERP analysis

Threatening, friendly, and neutral faces were presented to test the hypothesis of the facilitated perceptual processing of threatening faces. Dense sensor event-related brain potentials were measured while subjects viewed facial stimuli. Subjects had no explicit task for emotional categorization of the faces. Assessing early perceptual stimulus processing, threatening faces elicited an early posterior negativity compared with nonthreatening neutral or friendly expressions. Moreover, at later stages of stimulus processing, facial threat also elicited augmented late positive potentials relative to the other facial expressions, indicating the more elaborate perceptual analysis of these stimuli. Taken together, these data demonstrate the facilitated perceptual processing of threatening faces. Results are discussed within the context of an evolved module of fear (A. Ohman & S. Mineka, 2001).     

Born to fear: non-associative vs associative factors in the etiology of phobias

Poulton and Menzies (Behaviour Research & Therapy 40 (2001) 127-149) review two lines of evidence as supporting a non-associative pathway to the origins of "evolutionary relevant phobias". First, in retrospective studies of mode of onset some recall they have always had this fear. We review here solid evidence that retrospective recall is notoriously unreliable. Second, they note as many nonphobics recall relevant associative learning experiences as do phobics. We argue such studies are very inconclusive because they fail to consider many experiential and personality vulnerability (and invulnerability) factors that strongly impact the outcome of any putative learning experience. Their argument also does not explain the transition from developmental fears to phobias that is central to their thesis. Overall, we call for major methodological improvements in this area, in the context of theoretical developments pointing to interacting vulnerability and invulnerability factors.     

Proactive sensitizing effects of acute stress on acoustic startle responses and experimentally induced colitis in rats: relationship to corticosterone

In humans, some individuals develop a syndrome after trauma (post-traumatic stress disorder, PTSD) characterized by increased startle responses and lower than normal cortisol secretion. We explored a rat model using the acoustic startle response (ASR) as a behavioral indicator of the effect of a short series of shocks. Because gastrointestinal disorders have been associated with prior stress, we also studied the rats' vulnerability to a chemically-induced colitis. After initial blood sampling, 12 rats were exposed to ten 1 mA 5 s foot-shocks while 12 rats served as controls. Nineteen days later the rats were tested for ASR. Thirty trials (10 trials at each of 95, 105, and 115 dB, pseudo-randomized) were given. After exposure for 6 days to dextran sulphate sodium in their drinking water, the rats were killed and the colons examined for erosions. Shocked rats showed greater startle responses and more colonic erosion than unshocked rats, but the shock effects were significant only for animals with low initial plasma corticosterone levels. Shocked rats also showed higher levels of granulocyte marker protein (GMP) in their faeces. These results suggest that low corticosterone secretion may represent a marker for vulnerability to long term effects of shocks as indicated by increased startle responses and colonic pathology.     

‘Preparedness’ and ‘arousability’ as determinants of electrodermal conditioning

‘Arousability’, as defined through spontaneous electrodermal responses, has been empirically linked to anxiety, phobic symptoms and outcome of systematic desensitization. Previous data from our laboratory indicate that ‘preparedness’, as defined through potentially phobic vs. fear-irrelevant or ‘neutral’ conditioned stimuh, is an important determinant of electrodermal conditioning. The present experiment compared groups selected to be high or low in spontaneous responding during differential conditioning to potentially phobic or neutral stimuh. It was found that the effects of these two factors were essentially additive, i.e. conditioning and resistance to extinction were better for phobic stimuli and for high-arousal groups. The high-aroused group with phobic stimuh showed diffuse responding during acquisition, not differentiating between reinforced and unreinforced cues. However, it was the only group that failed to extinguish during 20 trials, which indicates that high arousal gives superior resistance to extinction particularly for phobic stimuli.