Who created the structure of intelligence theory?

• A. Spearman
• B. Vernon
• C. Thurstone
• D. Guilford

Answer: (D)

Guilford is the psychologist who created the Structure of Intellect theory. He argued that intelligence isn’t a single general ability but a system built from multiple dimensions organized along three independent axes: the type of mental operation (such as thinking, memory, divergent or convergent thinking, evaluation), the kind of material being manipulated (contents like figural, verbal, symbolic, or semantic), and the form in which the information is represented (products such as units, classes, relations, systems, transformations, implications). This framework yields many distinct abilities, illustrating why intelligence can’t be captured by one score alone. It contrasts with Spearman’s single g plus specific abilities, Thurstone’s primary mental abilities, and Vernon’s hierarchical model, which is why Guilford’s Structure of Intellect is the one that fits the description.