<unk>  is the scientific term describing a lack of emotional reactivity on the part of an individual. The precise boundary between the generally positive personality trait "serious" and the generally pathological<unk> " is impossible to describe precisely because it is culture specific and relies on subjective values. For example, the Japanese are often described as "unemotional" (even to the point of<unk>  in<unk> ") by Americans, and so the same individual may be considered to display a<unk>  in one culture and be merely "serious" or "unemotional" in another. See culture-specific syndrome.
Victims of post-traumatic stress syndrome are often said to display<unk> .  Veterans of intense combat have been described as having the thousand-yard stare (or thousand-yard gaze). Some of these veterans clearly suffer from a grave disorder commonly known as shell shock and may suffer from recurring nightmares or otherwise experience psychological distress. Others have developed less emotional reactivity as an arguably natural reaction to stress. Those displaying on this end of the spectrum may self-report dissociation but no psychological distress per se. At least one analyst of military basic training has described one primary goal of said training to be inducing this state of being, considered desirable for maintaining calm and rational decision-making capability during combat situations.[citation needed]<unk>  should not be confused with anhedonia although the two share some characteristics.  Anhedonia is the decrease or cessation of all feelings of pleasure (which thus<unk> s enjoyment, happiness, fun, interest, and satisfaction).  In the case of anhedonia, emotions relating to pleasure will not be expressed as much or at all because they are literally not experienced or are decreased.  A person with anhedonia may be unable to laugh or smile, for example.  Conversation will not be pleasurably stimulating for a person with extreme anhedonia, and thus that person may not be as responsive to conversation or its emotional subject matter.  Both<unk>  and anhedonia are considered negative symptoms of schizophrenia, meaning that they are indicative of a lack of something.  Other negative symptoms of schizophrenia include:  alogia, lack of concentration, social withdrawal (sometimes called social anhedonia), etc.  People with depression also sometimes experience anhedonia and it is a major component of the diagnosis for clinical depression.
One final consideration worth noting is that adults generally display less<unk> ion than children. This suggests blunting one's<unk>  may be a normal part of maturation.
Blunted affect
Labile affect
Jealousy
Euphoria
Satiety
Intrusive thoughts
Emotional detachment
Disgust