CORE 3 will utilize the Caltech Psychological Assessment Laboratory (PAL), whose mission is to provide recruitment and comprehensive, centralized testing of human research participants on psychological measures. Currently the PAL provides one day per week for obtaining measures of cognitive abilities, personality traits, psychiatric history, and psychosocial background, as part of the Caltech Brain Imaging Center. Researchers at Caltech use this information for inclusion and exclusion screening, for statistical use as covariates in group analyses, and for statistical comparison across subjects in research studies that investigate individual differences. This scope will be expanded for the Projects in the Conte Center, all of which include Aims regarding individual differences, and all of which rely on adequate recruitment, screening, and characterization of research participants. Thus, Core 3, like Core 2, will leverage an existing mechanism to enable a critical service for all of the four scientific Projects of the Center. Core 3 will not provide any clinical services. Core 3 will be directed by Dr. Lynn Paul, a licensed clinical psychologist; Dr. Ralph Adolphs will be a co-Pl. There are four Aims: subject recruitment; subject screening; basic psychological assessment (including demographics, IQ, basic perception); and assessment of problem solving skills relevant to the experiments described under the Projects (reasoning, logic, sophistication in math).