Tell Us Your Story: Investigating the Linguistic Features of Trauma Narrative

Tell Us Your Story: Investigating the Linguistic Features of Trauma Narrative Jeremy A. Luno (jaluno@memphis.edu) Department of Psychology / Institute for Intelligent Systems, University of Memphis 400 Innovation Drive, Memphis, TN 38152 USA J. Gayle Beck (jgbeck@memphis.edu) Department of Psychology / University of Memphis 202 Psychology Building, Memphis, TN 38152 USA Max Louwerse (maxlouwerse@gmail.com) Department of Psychology / Institute for Intelligent Systems, University of Memphis 400 Innovation Drive, Memphis, TN 38152 USA Tilburg Centre for Cognition and Communication (TiCC), Tilburg University PO Box 90153, 5000 LE, Tilburg, The Netherlands Abstract Linguistic features can predict several aspects of human behavior. Little is known, however, about whether syntactic, semantic and structural language features can also predict psychological disorders such as posttraumatic stress disorder (PTSD). The current study investigated whether the linguistic properties in trauma narratives written by survivors of a Motor Vehicle Accident (MVA), change as function of the intensity of PTSD symptoms. A short form diagnostic tool known as the Posttraumatic Stress Disorder Checklist (PCL) was used to determine the severity of participant PTSD symptomatology. Using a text capture paradigm participants were then asked to write a neutral narrative or a narrative that described their traumatic event. PCL scores were compared to linguistic variables from eight different computational linguistic algorithms. Results from this study suggested that the relative intensity of PTSD symptomatology affects syntactic, semantic, and structural aspects of the narrative. Keywords: Posttraumatic Stress Disorder; PTSD; Trauma Narrative; Linguistic Features. Introduction Language patterns can be good predictors of relations in the world. For instance, language statistics can predict the modality of a word (Louwerse & Connell, 2011), the iconic relationship of words (Louwerse, 2008), social networks (Hutchinson, Datla, & Louwerse, 2011), and even geographical locations of cities (Louwerse & Benesh, 2012; Louwerse & Zwaan, 2009). Language patterns have also shown to be predictors of aspects of human behavior. For instance, linguistic features predict fraudulent events (Louwerse, Lin, & Semin, 2010), predict an individual’s personality type (Gill, Nowson, & Oberlander, 2009), whether they are lying (Hancock, 2004), and even to what extent they visit their doctor’s office (Campbell & Pennebaker, 2003). Despite the predictive utility of language, there is very little computational linguistic research that investigates whether language features predict psychological symptoms such as those associated with Posttraumatic Stress Disorder (PTSD). Considering the ability of linguistic patterns to demonstrate mental processes and behaviors, and the concise delineations of PTSD symptomatology, the question can be raised whether linguistic patterns in written narratives from trauma survivors can be related to the severity of the trauma. More specifically, can language use reflect PTSD symptoms and their relative intensity? This research question was investigated in the current study. PTSD is an anxiety disorder diagnosed to persons having “experienced, witnessed, or having been confronted with events that involve potential death, serious injury, or a threat to the physical integrity of oneself or others” (DSM-IV, 2000, p. 467). PTSD patients will persistently re-experience the event, while simultaneously avoiding thoughts, and/or environmental reminders of the event, with some or all of these symptoms lasting for longer than one month. Specific symptoms include re-experiencing the traumatic event, avoiding thoughts of the event, mental/emotional numbing, as well as hyper-arousal. These symptoms are further delineated to include flashbacks, nightmares, sleep difficulties, and irritability. These symptoms are clustered into three overarching categories, “Re-experiencing Symptoms”, “Avoidance Symptoms”, and “Hyperarousal Symptoms (DSM-IV, 2000), even though not all symptoms are necessary for a PTSD diagnosis. In recent years the prevalence of PTSD has increased. Studies indicate that 20% of women and 9% of men will develop PTSD, while 6.8% of those diagnosed will live with the disorder indefinitely (Kessler et al., 1995). This increase is due not only to an awareness of the disorder in the clinical community, but also to the development of diagnostic tools such as the PTSD Checklist (PCL). The PCL is a 17-item self-report measure that monitors trauma symptomatology much like the 30-item structured interview, Clinician Administered PTSD Scale (CAPS). Despite the CAPS being the longstanding method to PTSD diagnosis, current research validates that the PCL correlates highly with the CAPS measure as well as with its diagnostic efficiency (Blanchard, Jones-Alexander, Buckley, & Fomeris, 1996).