ch 9.7 & 9.8 - Intelligence & the Brain, Sex Differences

Brain size & Intelligence

Brain size once believed to be related to intelligence

Einstein a brain was smaller than average

Well developed white matter pathways

Convolutions of the Cortex

Convolutions of the brain associated with scores on WAIS (correlation)

Number & size of gyri greater in species with more complex cognitive abilities

But, Avian brains lack convulsions, yet also capable of complex cognition

Relative Brain Size

relative brain size to body size, neuron density & organization all combine to allows complex cognitive processes

humans have the largest brain compared to their body size

sex differences

no differences in average intelligence scores

slight difference in sub scores: women stronger at verbal tests, men better at spacial abilities

statistical vs practical significance

Some research finds more variation in men