What is chronometry?

Arthur Jensen argued that reaction time (RT) chronometry taps the brain's underlying "neural oscillatory clock". In his view, every cognitive act relies on rhythmic cycles of neural excitation and inhibition, and faster, more stable oscillations allow sensory input to be registered, compared, and acted upon more quickly and consistently.

By measuring the central tendency (speed) and dispersion (intra-individual variability) of simple RTs, chronometric tasks provide an indirect window onto the tempo and regularity of these oscillations. Hence, shorter median RTs and smaller RT standard deviations are interpreted as markers of a high-frequency, low-noise neural timing mechanism that Jensen believed underpins g, the general factor of intelligence.