Remembering faces : the effects of emotional valence and temporal recency

It is known that the longer an information has been memorized, the stronger is its memory trace, and that emotionally-valenced information is more solid than neutral one. We investigated whether the emotional content of recent information might enhance its memory, making it as familiar as information known for a long time. We compared ERPs alternately recorded in response to old and solid information from long term memory (i.e., faces of popular movie stars), to recently acquired emotional information (faces of fictional characters), and to completely new information (faces of previously unknown people). Initially participants familiarized with the fictional police dossiers of 10 victims of dramatic deaths (recent faces), twice a day for seven days before EEG recordings. Recent faces were compared with faces of movie stars and unknown faces in an old/new recognition task. N200 and FN400 responses were affected by face familiarity (with no difference between old and recent faces), while parietal late positivity (LP) was sensitive to temporal recency, being it greater to old than recent faces. Interestingly, LP amplitude was similar for old and recent own-sex faces (victims) that were therefore equally memorable. It is shown that emotional memory can overcome temporal recency thus improving memory recall.