Final answer:
Calmness/relaxation is the emotion not activated by an increased rate of neural firing, as it is associated with the parasympathetic nervous system and a decreased neural firing rate.
Step-by-step explanation:
The emotion not activated by an increased rate of neural firing is calmness/relaxation. Emotions such as anger, sadness, and contentment are tied to different neural mechanisms, but typically, calmness or relaxation is associated with a decreased rate of neural firing and the activation of the parasympathetic nervous system, which promotes rest and digestion.
In contrast, emotions like anger would involve an increased neural firing rate and are often linked with the sympathetic nervous system's fight-or-flight response. This response includes physiological changes like pupil dilation, increased heart rate, and an increased oxygen supply to the lungs.