Neuroscience and Intelligence

• Does having a big head or brain have anything to do with intelligence?

Head and Brain Size

• Ratio of brain weight to body weight

• 1:5000

• 1:1500

• 1:220

• 1:180

• 1:50

Head and Brain Size

• Larger head size and larger brain size are associated with higher intelligence

• IQ test + brain imaging

Head and Brain Size

• Males have bigger brains• Are males more intelligent than females?• In one study, scientists converted the SAT

scores of 100,000 17- and 18-year-olds to a corresponding IQ score and found that males averaged 3.63 IQ points higher than the females

• The greater the brain tissue, the greater the ability for cognitive processing.

• Magnitude of the correlation is not very large

• Larger brains more neurons, greater myelination of neurons, etc.

• Larger brain size greater intelligence• Behaving intelligently larger brain size

Head and Brain Size• It may not be overall size that matters, but

size of certain sections beyond just the frontal lobe.

• perfectly normal-size brain, but certain parts of it were larger than normal, including the inferior parietal region, which

affects mathematical thought

Information Processing Speed

• Brain size only matters if the rest of the brain is organized properly to facilitate information processing.

• Let’s Play• Reaction Time• Higher IQ scores- faster/ shorter reaction time

Electrical Activity in the Brain• Actual neural transmission and intelligence• Nerve Conduction velocity (NCV)- speed with

which electrical impulses are transmitted along nerve fibers and across synapses

• Less consistency in results• Evoked Potential- electrical activity that is caused

by some external stimulus• Individuals who register such stimuli more quickly

score higher on intelligence tests than perceptually slower counterparts

Energy Consumption in the Brain• The extent to which the brain is “working” is the

rate at which it break downs glucose to compensate for the energy it uses

• When individuals are at rest and can engage in any activity they choose, those with higher intelligence demonstrate increased brain activity and their brains use more glucose.

• Higher intelligence- less energy• Ind’ls with intelligence have levels of brain

activity at their disposal and can use it more efficiently than less intelligent ind’ls.