Neuroscience of Personality and Intelligence Brain · The Amazing Brain · Measuring Brains · Cortical Thickness - grey matter (cortex) - quantify individuals' level of cortical thickness using MRI scanning - surface area of cortical thickness may vary - differences may relate to intelligence · White Matter Microstructure - measure intensity of system - gaps in system may affect information flow, perhaps affecting intelligence - measure white matter structure to see if more allows more info transfer · Neurotransmitter - measure activity of neurotransmitters using MRI Bigger brain · Smarter? Maybe not as elephants and whales have much larger brains. However, Pietschnig et al. (2015) found in 148 healthy and clinical mixed-sex samples (>8000 individuals) significant positive associations of brain volume and IQ that generalise over age (children and adults) - elephants and whales don't have intelligence humans do - not comparable because different evolutionary backgrounds - significant correlation w intelligence & brain volume · More neurons? Perhaps, but not much clear evidence yet of this. It's a somewhat mysterious, albeit, robust, association P-FIT (Parieto-Frontal Integration Theory) (Jung & Haier) · Robust evidence for the involvement of frontal and parietal regions in intelligence from lesions; fMRI; PET; neuroanatomy; converging neuroimaging evidence . Why? "We are inclined to propose that intelligence may be defined as the degree to which the frontal parietal network integrates and controls the flow of information throughout the brain" · brain more active when ppl do cognitive ability type tasks · specific brain structures affected in damage which affects intelligence · regions important in terms of intelligence, tell smth about structure White Matter Integrity as a neural foundation for general intelligence (Penke et al., 2012) White matter, processing speed, and g · Why do brain measures predict g? g is argued to reflect processing speed
· White matter integrity is a plausible neural marker of brain processing capacity - information transfer is greater with high integrity · Prediction: white matter will predict g via processing speed · segmentation of tracts · take brain and measure integrity of different tracts of info flow · g = general intelligence gray matter measures a 0.08 BIA 0.13 -0.26 0.31 0.25 0.12 b 0.08 -0.19 mediation model 0.02 0.03 0.30 0.31 Bigerd -0.81 g 0.25 -0.12 0.04 gspeed (processing speed) mediates WM and g · g = ability to transfer info around your brain quickly & efficiently · g = ability to transfer info around your brain quickly & efficiently · brain measures modestly predict g · can pathway be explained by processing speed? · ^ WM integrity, ^ higher g Eysenck · Eysenck was first to look @ personality from a neuro perspective · where in the brain is personality? . Suggested the human brain has two sets of neural mechanisms: excitatory and
inhibitory. The first relates to keeping the individual alert and the second relates to inactivity and lethargy. An individual seeks to maintain a balance between both these mechanisms and this is regulated by the ARAS. *homeostasis, under