Levels of Intelligence
Intelligence is the ability to find solutions to complex problems a life faces in a complex and uncertain environment. This cannot be captured by a standardized numerical score, such as IQ, that focuses on a narrow range of cognitive capabilities, such as working memory or verbal fluency. Intelligence also cannot be separated from the most essential property of all life forms, which is self-replication. This chapter briefly reviews the evolutionary history and diversity of intelligence from single-cell organisms to humans. The chapter includes a definition of intelligence and a discussion of how the nervous system works, the simple behavior of reflexes and the limitations of reflexes, connectome (the comprehensive map of all the connections in an animal’s nervous system), the multiple controllers for muscles, and the social nature of many behaviors. The chapter also includes a case study on eye movements.