Which theorist believed, smart people are smart and unintelligent people are not smart.

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

Answer: (C)

The main idea is that intelligence is driven by a single general factor, often called g, that influences performance across a wide range of cognitive tasks. Charles Spearman argued that people’s scores on different mental tests tend to rise and fall together because they share this common underlying ability. In other words, stronger overall mental ability leads to better performance in many areas, so those deemed “smart” across tests reflect a higher level of g, while those with lower g tend to show weaker performance in general.

This view fits the statement because it links broad, cross-domain performance to one overarching capacity. Other theorists proposed more nuanced structures—Guilford with many distinct abilities, Thurstone with several primary mental abilities, or Vernon with a hierarchical mix of g and group factors—so they don’t reduce intelligence to a single universal factor in the same way Spearman does.