-innate, biologically based, - arise from sensory experience, -same for all humans regardless of culture, and many animals as well, Sensory inputs go directly to the limbic areas
-Learned & social. Dependent on learning and social environment, sensory inputs must first go to the cortex (frontal lobe), and then to the limbic areas.
showed the amygdala is crucial part of the fear circuit. The amygdala is also heavily involved in sex, anger and aggression. The hypothalamus is also implicated.