A chink in the armor: The influence of training on generalization learning impairments after viewing traumatic stimuli

Studies have demonstrated that similarly to individuals with PTSD, non-PTSD individuals with repeated traumatic-exposure display selective impairments in hippocampal-related functions. A central example is their impaired generalization learning. Interestingly, previous findings revealed that the nature of this impairment varied as a function of occupation; while firefighters display impaired generalization of negative context, police crime scene investigators (CSI) display impaired generalization of negative cue. One possible explanation for these discrepancies may relate to the different job requirements and unique training. Specifically, firefighters are primed to regard the context during traumatic events whereas CSI police are primed to regard specific objects (cues) in the environment. The aim of the present study was to examine the interactive effect of exposure and training on generalization learning. Eighty-two healthy volunteers were exposed to either neutral or traumatic images while receiving instructions to refer either to the images' general contexts or to their specific cues. It was found that while both groups equally acquired and retained stimulus-outcome associations, only participants who were exposed to traumatic images showed impaired generalization learning. This impairment demonstrated a particular difficulty to generalize negative but not positive outcomes. Most importantly, as expected, there was a significant interaction between type of training and the observed impairments. Specifically, individuals who were previously trained to refer to general contexts showed a selective overgeneralization of negative contexts, while individuals who were trained to refer to specific cues displayed a selective overgeneralization of negative cues. The results suggest that trauma exposed individuals show the most vulnerability in precisely the areas in which they were most trained. We discuss the ways in which improving generalization learning may impact individuals' process of trauma recovery and might set the ground for developing treatment and prevention methods.