No-think, No drink? Assessing the ability of reconsolidation interference by intentional forgetting to suppress alcohol memories in hazardous drinkers

Memory reconsolidation offers an opportunity to modify previously consolidated memories by first reactivating them. The process is triggered by the presentation of retrieval cues (reminders of the memory to be reactivated). However, reconsolidation is not universally triggered upon retrieval. Here we investigate one boundary condition thought to constrain memory reactivation: retrieval length. We also investigate the effects of a novel post-retrieval manipulation: intentional suppression. We assessed this with the think/no-think (TNT) task, in a clinically relevant sample of hazardous drinkers, using alcohol-related paired associate learning. 73 participants took part in four online sessions. On the first session participants were required to learn 36 image-word pairs. On the second session participants received 0, 4, 18 or 36 retrieval cues followed by the TNT task. The recall of the pairs was assessed 2 and 7 days after the retrieval + TNT procedure. The 4-trial retrieval procedure was the most consistent with triggering memory reconsolidation. This group showed greater practice effects and was the only group in which suppression-induced forgetting was observed at test. However, suppression-induced forgetting of alcohol cues was lower than in normative samples, indicating that intentional forgetting effects may depend upon population, salience of material and time between suppression and retrieval.