Displacement Activities as a Behavioral Measure of Stress in Nonhuman Primates and Human Subjects

Abstract

Traditionally, research on human stress has relied mostly on physiological and psychological measures with a relatively minor emphasis on the behavioral aspects of the phenomenon. Such an approach makes it difficult to develop valid animal models of the human stress syndrome. A promising approach to the study of the behavioral correlates of stress is to analyze those behavior patterns that ethologists have named displacement activities and that, in primates, consist mostly of self-directed behaviors. In both nonhuman primates and human subjects, displacement behavior appears in situations characterized by social tension and is likely to reflect increased autonomic arousal. Pharmacological studies of nonhuman primates have shown that the frequency of occurrence of displacement behavior is increased by anxiogenic compounds and decreased by anxiolytic drugs. Ethological studies of healthy persons and psychiatric patients during interviews have found that increased displacement behavior not only correlates with a subjective feeling state of anxiety and negative affect but also gives more veridical information about the subject's emotional state than verbal statements and facial expression. The measurement of displacement activities may be a useful complement to the physiological and psychological studies aimed at analyzing the correlates and consequences of stress.

Handedness as a marker of cerebral lateralization in children with and without autism

“…These findings are consistent with studies that have reported a left-handed preference for self-directed face touching in adults who were otherwise right-handed [87], and a further study that revealed that individuals reflexively raise their non-dominant hand to protect their faces [88]. Although untested in the current study, it is possible that SDBs might represent displacement behaviors found to be correlated with levels of stress in studies of both human and nonhuman primates [89].…”

Stress reduction through consolation in chimpanzees

“…Postconflict stress levels were assessed by using self-directed behaviors (31,32). In particular, we used rates of self-scratching (bouts per minute) and the duration of self-grooming (seconds per minute), both previously used in postconflict studies (6).…”

“…We used self-directed behaviors, such as self-scratching and self-grooming, as indicators of stress because these are known to increase in primates under stressful conditions (31,32). The link between selfdirected behaviors and stress levels is further supported by pharmacological evidence (33).…”

Why are bystanders friendly to recipients of aggression?

“…While direct evidence that these behaviors are linked to stressrelated physiological changes is lacking, there is a growing body of circumstantial evidence that suggests that self-directed behaviors are reliable indicators of stress and anxiety in primates. 55,56 Indirect physiological evidence is provided by the fact that allo-grooming reduces both self-directed behaviors 50 and heart rate. 51,57 There is also pharmacological evidence to support the link, as anxiogenic and anxiolytic drugs selectively increase and decrease levels of self-directed behavior respectively.…”