lizard brain

== English == === Noun === lizard brain (plural lizard brains) (informal) The most primitive part of the brain; the brain stem. (by extension) Any part of a person's psyche or personality dominated by instinct or impulse rather than rational thought. Synonyms: id, reptilian brain (by extension) Any part of a person's mind concerned with automatic, repetitive tasks rather than emotion. ==== Derived terms ==== lizard-brained