Reconciling change blindness with long-term memory for objects

How can we reconcile remarkably precise long-term memory for thousands of images with failures to detect changes to similar images? We explored whether people can use detailed, long-term memory to improve change detection performance. Subjects studied a set of images of objects and then performed recognition and change detection tasks with those images. Recognition memory performance exceeded change detection performance, even when a single familiar object in the postchange display consistently indicated the change location. In fact, participants were no better when a familiar object predicted the change location than when the displays consisted of unfamiliar objects. When given an explicit strategy to search for a familiar object as a way to improve performance on the change detection task, they performed no better than in a 6-alternative recognition memory task. Subjects only benefited from the presence of familiar objects in the change detection task when they had more time to view the prechange array before it switched. Once the cost to using the change detection information decreased, subjects made use of it in conjunction with memory to boost performance on the familiar-item change detection task. This suggests that even useful information will go unused if it is sufficiently difficult to extract.     

An implicit basis for the retention benefits of random practice

The cognitive effort explanations of contextual interference (CI) and implicit motor learning represent a paradox in which cognitive involvement is seen to be advantageous or disadvantageous for learning. The authors aimed to resolve this paradox by measuring cognitive effort and working memory dependence during low and high CI practice on two Australian Rules Football tasks (kicking and handball). Measures of cognitive effort included: kicking and handball outcome performance during acquisition and during a test of retention, performance on a probe reaction time task during a sample of acquisition trials, and self-reported levels of cognitive effort. Measures of implicit and explicit learning included kicking and handball performance during a secondary task transfer, and self-report verbal protocols (number of verbal rules and hypotheses reported). The results suggest that high CI may cause an implicit mode of learning, perhaps due to the interference caused by task switching. However, these findings are restricted to the more complex of the 2 tasks (kicking).     

Attention and relative novelty in human perceptual learning

Four experiments examined the role of attention in human perceptual learning. In Experiment 1, participants were preexposed to a pair of visual (checkerboard) stimuli AX and BX, with common elements X and unique features A and B. A same-different task was then used to assess discrimination of AX and BX and a pair of control stimuli, CY and DY. In addition, participants' eye movements were recorded to assess the role of attentional processes. The results showed that preexposure enhanced discrimination between AX and BX. Furthermore, participants showed greater attention to the preexposed unique features A and B than to the novel unique features C and D, as measured by the eye gaze monitor. Experiments 2 and 3 examined the prediction that perceptual learning is due to the relative familiarity of the common and unique stimulus features. Experiment 4 replicated the intermixed-blocked effect and showed that the way in which AX and BX are presented is also important for perceptual learning. The results generally support the idea that intermixed preexposure to AX and BX increases attention to the unique stimulus features A and B. Some aspects of the results are consistent with a relative novelty account, whereas others implicate a high-level attentional process that is not driven by stimulus novelty.     

Young adult female fragile X premutation carriers show age- and genetically-modulated cognitive impairments

The high frequency of the fragile X premutation in the general population and its emerging neurocognitive implications highlight the need to investigate the effects of the premutation on lifespan cognitive development. Until recently, cognitive function in fragile X premutation carriers (fXPCs) was presumed to be unaffected by the mutation. Here we show that young adult female fXPCs show subtle, yet significant, age- and FMR1 gene mutation-modulated cognitive impairments as tested by a quantitative magnitude comparison task. Our results begin to define the neurocognitive endophenotype associated with the premutation in adults, who are at risk for developing a neurodegenerative disorder associated with the fragile X premutation. Results from the present study may potentially be applied toward the design of early interventions wherein we might be able to target premutation carriers most at risk for degeneration for preventive treatment.     

Compulsive Internet Use Among Adolescents: Bidirectional Parent–Child Relationships

Although parents experience growing concerns about their children’s excessive internet use, little is known about the role parents can play to prevent their children from developing Compulsive Internet Use (CIU). The present study addresses associations between internet-specific parenting practices and CIU among adolescents, as well as the bidirectionality of these associations. Two studies were conducted: a cross-sectional study using a representative sample of 4,483 Dutch students and a longitudinal study using a self-selected sample of 510 Dutch adolescents. Results suggest that qualitatively good communication regarding internet use is a promising tool for parents to prevent their teenage children from developing CIU. Besides, parental reactions to excessive internet use and parental rules regarding the content of internet use may help prevent CIU. Strict rules about time of internet use, however, may promote compulsive tendencies. Finally, one opposite link was found whereby CIU predicted a decrease in frequency of parental communication regarding internet use.     

Frontal cortex functioning in the infant broader autism phenotype

Atypical attention has been proposed as a marker of the broader autism phenotype. In the present study we investigated this and the related process of inhibitory control at the youngest possible age through the study of infant siblings of children with an autism spectrum disorder (Sibs-ASD). Both attention and inhibition have been related to the frontal cortex of the brain. Nine- to ten-month-old Sibs-ASD and low-risk control infants completed the Freeze-Frame task, in which infants are encouraged to inhibit looks to peripherally presented distractors whilst looking at a central animation. The attractiveness of the central stimulus is varied in order to investigate the selectivity of infants’ responses. In line with previous studies, it was found that a subset of Sibs-ASD infants had difficulty disengaging attention from a central stimulus in order to orient to a peripheral stimulus. The Sibs-ASD group also showed less Selective Inhibition than controls. However, Sibs-ASD infants did demonstrate Selective Inhibitory Learning. These results provide preliminary evidence for atypical frontal cortex functioning in the infant broader autism phenotype.     

An extended motor network generates beta and gamma oscillatory perturbations during development

This study examines the time course and neural generators of oscillatory beta and gamma motor responses in typically-developing children. Participants completed a unilateral flexion–extension task using each index finger as whole-head magnetoencephalography (MEG) data were acquired. These MEG data were imaged in the frequency-domain using spatial filtering and the resulting event-related synchronizations and desynchronizations (ERS/ERD) were subjected to voxel-wise statistical analyses to illuminate time–frequency specific activation patterns. Consistent with adult data, these children exhibited a pre-movement ERD that was strongest over the contralateral post-central gyrus, and a post-movement ERS response with the most prominent peak being in the contralateral precentral gyrus near premotor cortices. We also observed a high-frequency (∼80 Hz) ERS response that coincided with movement onset and was centered on the contralateral precentral gyrus, slightly superior and posterior to the beta ERS. In addition to pre- and post-central gyri activations, these children exhibited beta and gamma activity in supplementary motor areas (SMA) before and during movement, and beta activation in cerebellar cortices before and after movement. We believe the gamma synchronization may be an excellent candidate signal of basic cortical motor control, as the spatiotemporal dynamics indicate the primary motor cortex generates this response (and not the beta oscillations) which is closely yoked to the initial muscle activation. Lastly, these data suggest several additional neural regions including the SMA and cerebellum are involved in basic movements during development.     

Effects of COMT genotype on behavioral symptomatology in the 22q11.2 Deletion Syndrome.

The 22q11.2 Deletion Syndrome (DiGeorge/velocardiofacial syndrome) is associated with elevated rates of psychosis, and is also characterized by severe attentional difficulties and executive dysfunction. Behavioral manifestations of this syndrome could result from haploinsufficiency of the catechol-O-methyltransferase (COMT) gene, located within the 22q11 region. The goal of the present study was to examine COMT genotype in relation to behavioral symptomatology in this syndrome. Val158/108Met was genotyped in 38 patients (16 Met/-, 22 Val/-) with confirmed 22q11.2 deletions who had received the Child Behavior Checklist (CBCL) as part of a comprehensive evaluation. Results indicated that the Val genotype was associated with significantly greater internalizing and externalizing behavioral symptomatology in children with 22q11.2 deletions. Val allele status was associated with a greater-than-four-fold increase in risk for clinically significant behavior problems in children with this syndrome. These data are consistent with previous findings of increased psychopathology associated with the Val genotype in normal individuals and suggest that a functional genetic polymorphism in the 22q11 region may influence behavior in individuals with COMT haploinsufficiency.