Neural efficiency hypothesis

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

The neural efficiency hypothesis says that people with higher intelligence use their brains more efficiently. When solving the same thinking task, smarter individuals show less brain activation and use fewer neural resources than those with lower intelligence.

How it started and what it means
- In 1988, Haier and colleagues used PET scans to measure brain activity while participants did cognitive tasks, like Raven’s Progressive Matrices. They found that people with higher IQs had lower brain glucose metabolism during task performance, even when they did well.
- This suggested that smarter brains work more efficiently, getting the job done with less energy.

What later research showed
- The idea has been tested beyond simple intelligence tests. Some studies used decision-making tasks and even looked at athletes. Across these tasks, higher intelligence or expertise often meant using only the brain areas that are needed, with lower activity in other areas and faster responses.
- In some cases, very smart individuals used more brain activity when tasks were harder, indicating flexible use of brain regions to meet task demands.

What can influence the neural efficiency pattern
- Task difficulty: The neural efficiency pattern tends to hold for easy tasks. For harder tasks, highly intelligent people may show more brain activation as they recruit extra resources.
- Sex and task type: Some research suggests that sex and the kind of task matter. For example, verbal tasks may show stronger neural efficiency patterns in women, while figural (visual-spatial) tasks may show such patterns more in men.

Takeaways and limitations
- Overall, the neural efficiency hypothesis has good support, but it isn’t universal. The amount and pattern of brain activity depend on how hard the task is, the person’s sex, and the type of task.
- Early studies often used uniform tasks and mostly male participants, so modern research emphasizes a more nuanced view: higher intelligence is linked to more efficient brain processing, especially for easier tasks, but the relationship can change with task demands and context.