The study of internal attention and its dysregulation has evaded direct cognitive-experimental study for decades. Despite the theorized functional importance of internal attention (to thoughts) and external attention (to sensory information) in cognitive vulnerability and mental health, research has focused almost exclusively on the latter. We thus developed the Simulated Thoughts Paradigm (STP) to simulate the content and experience of thinking. STP is grounded in embodied cognition accounts of verbal thought as well as behavioral, phenomenological and cognitive neuroscience of own-voice perception and self-representations. Utilising STP we present participant’s own idiographic negative (or neutral) self-referential thoughts, sentences recorded in their own voice (e.g., “I am a failure”), as stimuli within cognitive-experimental tasks. Consistent with theory, we found evidence of serial multiple mediation wherein (1) emotional reactivity to negative self-referential thoughts predicts (2) degree of difficulty disengaging internal attention from those thoughts which predicts (3) degree of cognitive vulnerability (e.g., negative repetitive thinking) which predicts (4) degree of anxiety and depression symptomatology. The study and findings may have implications for the experimental study of internal attentional (dys)control as well as for experimental therapeutics designed to train meta-awareness of- and attentional control over- one’s thoughts. Finally, we propose that the integration of STP with natural language processing may facilitate novel avenues for studying maladaptive thought processes. For example, the dataset of audio recorded STP stimuli generated in this study may be used as train-test set for machine learning approaches. Such approaches may identify novel semantic and/or sonic features (of STP stimuli) which differentiate (classify) between emotionally reactive states and/or persons with heightened levels of rumination or worry.