The Architecture of Intelligence: Converging Evidence From Studies of Humans and Animals

A person's performance across multiple cognitive tests tends to covary. This ubiquitous observation suggests that various cognitive domains are regulated in common, and this covariance underlies the interpretation of many quantitative tests of intelligence. We find that, as in humans, differences in intelligence exist across genetically heterogeneous mice. Specifically, we have observed a covariance in the performance of mice across diverse tests of learning, reasoning, and attention. As in humans, the processing efficacy of working memory is both correlated with animals' general cognitive abilities and may in some instances serve to regulate behaviors indicative of intelligence. Beyond its axiomatic significance in demonstrating the evolutionary conservation of a cognitive trait, studies of mice may provide unique opportunities to assess the molecular (e.g., brain-specific RNA expression; transgenics) and neuroanatomic substrates for intelligence. One such approach is briefly described here. Using this approach, we have determined that the signaling efficacy of the dopamine D1 receptor in the prefrontal cortex is one potential link between performance on both working-memory tasks and tests of intelligence. In combination, studies of both humans and nonhuman animals provide converging lines of evidence that might evade either approach in isolation.