Short-term storage and mental speed account for the relationship between working memory and fluid intelligence.

Here, we explore the role of short-term storage, mental speed, processing efficiency, and controlled attention to account for the relationship between working memory and fluid intelligence. Ninety-six secondary school students were assessed by several tests and tasks to tap these psychological constructs. Specifically, each construct was measured by two tests or tasks from different content domains (verbal-numerical and spatial). The findings show that short-term storage and, to a lesser degree, mental speed, account for the relationship between working memory and fluid intelligence. Further, processing efficiency and controlled attention do not play a significant role.