Feeling psychologically restrained: the effect of social exclusion on tonic immobility.
BACKGROUND
A variety of studies have demonstrated posttraumatic stress disorder (PTSD) symptoms in victims of bullying. Because bullying with only relational aggression, such as social exclusion, does not involve physical aggression that could explain PTSD symptoms, it remains unclear why these relational aggression situations are also linked to PTSD symptoms.


OBJECTIVE
The aim of the present study was to investigate whether the fear-response tonic immobility (Ti) can occur during social exclusion. Since Ti, as an indicator of peritraumatic dissociation, is an important predictor of PTSD symptoms, we expected that the presence of Ti during social exclusion might contribute to possible explanations of PTSD symptoms in victims of relational aggression.


METHODS
Social exclusion was manipulated by a virtual Cyberball game in which participants were excluded and included by virtual confederates. During the game, Ti was measured, both physiologically (heart rate) and psychologically (subjective symptoms). Also, the underlying concepts of Ti, high levels of fear and psychological restraint (threatened sense of control), were measured.


RESULTS
Excluded participants experienced higher levels of subjective and physiological Ti symptoms (lower heart rates) in comparison to social inclusion. Also, as expected, social exclusion resulted in higher levels of fear and psychological restraint in comparison to social inclusion.


CONCLUSIONS
Social exclusion can evoke symptoms of Ti, fear, and psychological restraint, which might be important mechanisms to consider in explaining PTSD symptoms after relational forms of bullying in the absence of physical aggression.


CONCLUSIONS
The sample only contains healthy, female participants. Whether our results translate to bullying victims of relational aggression is therefore not known. Also, the physiological measurement of Ti (average heart rate) was rather limited and could be expanded in future studies.
Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands.
Nora
N
Mooren
Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands ; Overwaal, Centre for Anxiety Disorders Overwaal, Nijmegen, The Netherlands.
Agnes
A
van Minnen
PTSD; Tonic immobility; bullying; fear; psychological restraint; relational aggression; social exclusion; trauma