The term was based on a 1973 hostage incident, in which one hostage gradually changed from being merely a pleading defender in the interests of her own survival to being a passionate advocate on behalf of her captors. The term contains the following five elements: (1) a period of captivity with an apparently ruthless captor, (2) the hostage's perception that survival depends on acceding to the captor's demands, (3) the victim's conversion to perceptions of the captors as friends and of authorities as enemies, and (4) the victim's acting out of the changed feelings toward the captor, and (5) persistence of the changed feelings beyond the duration of the hostage event. Victims may experience other perceptual changes which resemble the Stockholm Syndrome but which should not be confused with it. For example, the true syndrome involves lack of a critical, self-questioning faculty, although both the syndrome and its pseudo-analog contain the seeming necessity to explain the captor's bad treatment of the victim. Hacker's 'poor devil' theory is less pertinent as an explanation of the syndrome than it is of the analog, because the syndrome appears to be sexually generated. Analysis of the stages of feelings involved in the syndrome also suggest that the victim identifies with the aggressor as a human being rather than with the aggression and that the hostage-captor relationship is a symbiotic one which also changes the hostage-taker. A description of sympathetic feelings produced by the death of a man-eating leopard illustrates the feeling of relief experienced by victims when the captor is rendered powerless. Further research into hostages' perceptions toward their captors is needed, and should be based on evidence given by the hostages themselves. Forty-five footnotes are provided.