To test this possibility, we obtained genotype and cognitive phenotype data from the Collaborative Study of the Genetics of Alcoholism (COGA). Using this dataset, we tested the association between genotypes and three of the most relevant phenotypes, namely scores on the Wechsler Adult Intelligence Scale (WAIS) Block Design, WAIS Digit Symbol and WAIS Information tests. These tests were designed to measure aspects of perceptual organization, processing speed and verbal comprehension, respectively [29].
