Mouse tracking: a tool to detect fake good and fake bad behaviours

The rate of suspected simulation in the clinical population is estimated to be around 20%. This data underlines important consequences both in terms of health care cost and in terms of absences from work, as well as it introduces a strong issue in the legal context for the assessment of the psychological damage and the evaluation of mental insanity. Similarly, it is estimated a dissimulation rate of 30% in job applicants and parents who are involved in child custody litigations. Presently, few instruments offer clinical support in the identification of psychiatric disorders simulation and dissimulation. This contribute will introduce a new method for the automatic detection of fake bad and fake good behaviours that exceed the limitations of the currently available instruments. The method proposed is based on kinematic analysis of mouse movements while the patient is engaged in a double choice computerized questionnaire that investigates the presence of certain psychological symptoms. Recent studies proved that the kinematics of hand movements may provide a reliable track of the mental processes underlying a task and can be effective in detecting the processes of a lie production. Based on this scientific evidence, we analysed the response trajectories of groups of subjects instructed to simulate or dissimulate a psychological disorder (depression, anxiety disorder, personality disorder) while they are answering to questions about their symptoms. The analysis of the kinematic parameters showed a statistically significant difference between fakers and control groups, both in the shape of the trajectory along time and in the response time