The dimension of somatization is related to an increased color-word Stroop effect

Abstract

CONGRUENT INCONGRUENT RED RED Example Stroop Stimuli The classic color-word Stroop task is a wellknown and widely used neuropsychological measure that requires individuals to view color-words (e.g., “red”) in an ink color that is either congruent (the word “red” in red ink) or incongruent ( the word “red” in blue ink). The individual’s task is to identify the color of the ink while ignoring the written word. During the task, the individual’s average reaction time within each condition is measured. The Stroop effect refers to an increase in reaction time in identifying the color of the incongruent compared to the congruent stimuli. Recent neuroimaging reviews indicate that the anterior cingulate cortex (ACC) is involved in regulating cognitive demands during the Stroop task, including error detection and response conflict (Bush et al., 2000; Carter and van Veen, 2007). Therefore, it has been suggested that performance on the Stroop task is sensitive to individual differences in ACC functioning (Carter et al., 1995). A recent study has demonstrated that an increase in the dimension of delusion-proneness, or propensity to hold beliefs that are dismissed as false or bizarre by members of the same socio-cultural group (Gilleen & David, 2005), was related to a greater color-word Stroop effect (Orem & Bedwell, 2010). Therefore, this association may relate to a deficiency in the ACC in monitoring errors in beliefs vs. reality. As different dimensions of psychopathology include different levels of delusional thought processes, we were interested in examining how a wide range of dimensions of psychopathology would relate to the Stroop effect. The Brief Symptom Inventory, or BSI, assesses for a wide variety of psychological symptoms. Within the various domains assessed by this measure, Somatization, Paranoid Ideation, and Psychoticism all include varying levels of delusionproneness. Specifically, Somatization includes complaints of physical symptoms that appear to be related primarily to psychological distress, Paranoid Ideation includes explicit delusional thought, and Psychoticism includes hallucinations and perceived thought control. Therefore, we hypothesized that the Stroop effect would be positively related to these three domains, supporting the ACC’s role in monitoring errors in beliefs vs. reality. Participants:  42 undergraduate students  Mean age of 19.30 years (SD = 2.28; Range = 18 – 32)  71.4% Female  71.4% Caucasian