Brain and Intelligence – Findings in Neurpsychology

There is a general a belief that a person with a large head and high forehead is likely to be intelligent. But, more than brain size, intelligence shows meaningful relations to brain efficiency. Psychologist Richard J. Haier and his colleagues found that the brains of people who perform well on mental tests consume less energy than the brains of poor performers.
Haier measured brain activity with a PET scan. PET (Positron Emission Tomography) scan detects positrons (subatomic particles) emitted by weakly radioactive glucose (sugar) as it is consumed by the brain. Since the brain runs on glucose, a PET scan shows which brain areas are used more energy. Higher energy use is assumed to correspond with higher activity. Haier applied this scan while the subjects took a difficult reasoning test.
Surprisingly for the Haier, the brains of those who scored lowest on the test used the most glucose. Although we might assume that smart brains are hard working brains, the reverse appears to be true. Brighter subjects actually used less energy than poor performers did. Haier believes this shows that intelligence is related to brain efficiency. Less efficient brain work harder and still accomplish less (Obligations to “Essential of Psychology – 6th ed. By Dennis Coon)