Typicality and Familiarity Effects in Children\u27s Memory: the Interaction of Processing and the Knowledge Base.

Third- and sixth-graders and adults participated in an experiment based upon Hunt and Einstein\u27s (1981) theory which relates study activities or processing task to subsequent memory performance. Participants performed a processing task designed to emphasize either relational or item-specific information. In addition, the information about the words available in each subject\u27s knowledge base was measured in two ways: relational information was assessed with a typicality rating task and item-specific information was assessed with an attribute listing task. The experiment consisted of three phases. In the first phase subjects performed one of two processing tasks on a list containing typical, atypical and unfamiliar exemplers of a semantic category. One group of subjects sorted the words into categories (the relational task) the other group rated the words for pleasantness (the item-specific task). In the second phase, subjects\u27 memory for the words was tested on a free recall test. In the third phase the knowledge base assessment tasks were performed. The knowledge base measures indicated: the relative amount of relational versus item-specific information available for typical, atypical and unfamiliar words is different for each type of word and that amount of relational and item-specific information in the knowledge base changes with age. As predicted by the theory, recall was influenced by the interaction of word type with processing task. Finally, parallels between free recall results and the knowledge base measures indicated that knowledge base development interacts with the processing task to influence what is recalled by subjects at the three age levels

Genomic Relationships, Novel Loci, and Pleiotropic Mechanisms across Eight Psychiatric Disorders

Genetic influences on psychiatric disorders transcend diagnostic boundaries, suggesting substantial pleiotropy of contributing loci. However, the nature and mechanisms of these pleiotropic effects remain unclear. We performed analyses of 232,964 cases and 494,162 controls from genome-wide studies of anorexia nervosa, attention-deficit/hyper-activity disorder, autism spectrum disorder, bipolar disorder, major depression, obsessive-compulsive disorder, schizophrenia, and Tourette syndrome. Genetic correlation analyses revealed a meaningful structure within the eight disorders, identifying three groups of inter-related disorders. Meta-analysis across these eight disorders detected 109 loci associated with at least two psychiatric disorders, including 23 loci with pleiotropic effects on four or more disorders and 11 loci with antagonistic effects on multiple disorders. The pleiotropic loci are located within genes that show heightened expression in the brain throughout the lifespan, beginning prenatally in the second trimester, and play prominent roles in neurodevelopmental processes. These findings have important implications for psychiatric nosology, drug development, and risk prediction.Peer reviewe