Short answers, pulled from the story.
Affect in psychology is the underlying experience of feeling, emotion, attachment, or mood. It encompasses positive states such as happiness, joy, and excitement, as well as negative states such as sadness, anger, fear, and disgust. It is understood as a combination of three components: emotion, mood, and affectivity.
Wilhelm Wundt developed the modern conception of affect in the 19th century. The term derives from the German word Gefuhl, meaning "feeling."
Affective states vary along three principal dimensions: valence, arousal, and motivational intensity. Valence is the positive-to-negative spectrum of evaluation; arousal is measurable as activation of the sympathetic nervous system; motivational intensity refers to the strength of the urge to move toward or away from a stimulus.
The Positive and Negative Affect Schedule (PANAS) is the most commonly used measure in scholarly research on affect. It is a lexical measure consisting of 20 single-word items developed in a North American setting, including words such as excited, alert, and determined for positive affect, and upset, guilty, and jittery for negative affect. An internationally validated short form, the I-PANAS-SF, was later developed using two 5-item scales.
Affects high in motivational intensity, such as anger and fear, narrow cognitive scope so that attention focuses on central information. Affects low in motivational intensity, such as sadness, broaden cognitive scope and allow for faster global interpretation. This pattern is evolutionarily adaptive because high-intensity states like fear prompt focused, goal-directed action.
Alexithymia is a subclinical phenomenon involving difficulty in identifying and describing feelings and in distinguishing feelings from the bodily sensations of emotional arousal. It is closely related to low affect tolerance. Research by Dalya Samur and colleagues found that persons with alexithymia show correlations with increased suicide rates, mental discomfort, and deaths.