Acquired Equivalence in U.S. Veterans With Symptoms of Posttraumatic Stress: Reexperiencing Symptoms Are Associated With Greater Generalization

The severity and number of reexperiencing symptoms (e.g., flashbacks) show considerable variability across individuals with posttraumatic stress disorder (PTSD). One interpretation of reexperiencing symptoms invokes generalization: Specifically, the traumatic memory may be stored in such a way that neutral stimuli that only vaguely resemble some feature of the traumatic event are sufficient to trigger the memory. If this is the case, then individuals with higher levels of reexperiencing symptoms might show greater generalization, even in contexts unrelated to trauma. In the current study, an acquired equivalence test was used to assess associative learning and generalization in 114 U.S. veterans who were also given a test of declarative memory. PTSD symptoms were rated by the veteran. After adjusting for demographic variables, psychoactive medication use, and initial learning, regression analyses showed that the number of PTSD reexperiencing symptoms significantly improved the model for generalization (β = -23, R² = .34) but not associative learning or declarative memory. The results support the idea that generalization is linked to reexperiencing symptoms, is not limited to learning about traumatic events, and can emerge even in a relatively innocuous computer-based learning task.