Fewer intrusive memories in aphantasia: using the trauma film paradigm as a laboratory model of PTSD

When we live through a traumatic event some of us will go on to experience uncontrollable unpleasant memories of the event. These intrusive memories are one of the hallmarks of post-traumatic stress disorder. Intrusive memories or flashbacks are typically described as visual, and their vividness predicts the severity of PTSD. If visual imagery is central to the development and continuation of flashbacks then people without visual imagery (aphantasia) should experience less, or different, intrusive memories. To test this, a group of individuals with aphantasia and a group with visual imagery underwent a lab-based PTSD model: the trauma film paradigm. Aphantasic individuals reported fewer intrusions immediately after watching the traumatic film, as well as fewer intrusions in a digital diary app over the course of a week. Despite the significant reduction in intrusive memories, aphantasic individuals still reported having some intrusions, however, the sensory qualities of these intrusions were markedly different from individuals with visual imagery. While individuals with visual imagery reported their intrusions as being mostly visual, aphantasic individuals reported mostly verbal intrusions. These findings demonstrate that visual imagery is related to the number of intrusive memories experienced after witnessing a traumatic event, which may have important implications for the development of PTSD. Further, it does appear that aphantasic individuals can experience intrusions, albeit less frequently and in a different format than people with visual imagery.