ORIGINAL ARTICLE Event-related potentials of emotional and neutral memories: The role of encoding position and delayed testing Janine Wirkner 1 | Carlos Ventura-Bort 2 | Paul Schulz 1 | Alfons O. Hamm 1 | Mathias Weymar 2 1 Department of Biological and Clinical Psychology, University of Greifswald, Greifswald, Germany 2 Department of Psychology, University of Potsdam, Potsdam, Germany Correspondence Janine Wirkner, Department of Biological and Clinical Psychology, University of Greifswald, Franz-Mehring-Str. 47, 17487 Greifswald, Germany. Email: janine.wirkner@uni-greifswald.de Abstract Previous research found that memory is not only better for emotional information but also for neutral information that has been encoded in the context of an emotional event. In the present ERP study, we investigated two factors that may influence mem- ory for neutral and emotional items: temporal proximity between emotional and neutral items during encoding, and retention interval (immediate vs. delayed). Forty- nine female participants incidentally encoded 36 unpleasant and 108 neutral pictures (36 neutral pictures preceded an unpleasant picture, 36 followed an unpleasant pic- ture, and 36 neutral pictures were preceded and followed by neutral pictures) and participated in a recognition memory task either immediately (N 5 24) or 1 week (N 5 25) after encoding. Results showed better memory for emotional pictures rela- tive to neutral pictures. In accordance, enhanced centroparietal old/new differences (500–900 ms) during recognition were observed for unpleasant compared to neutral pictures, most pronounced for the 1-week interval. Picture position effects, however, were only subtle. During encoding, late positive potentials for neutral pictures were slightly lower for neutral pictures following unpleasant ones, but only at trend level. To summarize, we could replicate and extend previous ERP findings showing that emotionally arousing events are better recollected than neutral events, particularly when memory is tested after longer retention intervals. Picture position during encod- ing, however, had only small effects on elaborative processing and no effects on memory retrieval. KEYWORDS attention, emotion, ERPs, memory, old/new effect, serial position effect 1 | INTRODUCTION There is numerous evidence that emotionally arousing stim- uli draw more attention than neutral stimuli, and that this preferential processing results in better long-term memory (LaBar & Cabeza, 2006; Lang, Bradley, & Cuthbert, 1997). ERPs are good neural measures to study such attentional and mnemonic processes due to their advantage in high tem- poral resolution. For instance, during picture viewing, emo- tional compared to neutral pictures elicit larger late positive potentials (LPPs) starting at about 400 ms poststimulus (Cuthbert, Schupp, Bradley, Birbaumer, & Lang, 2000; Schupp et al., 2007; Weymar, Schwabe, L€ ow, & Hamm, 2012; Wirkner et al., 2017). This increased positive potential has been related to more elaborate stimulus processing, reflecting stimulus-driven motivated attention toward emo- tionally arousing items (Cuthbert et al., 2000). When testing recognition memory, emotional pictures are better remem- bered than neutral pictures and elicit a stronger ERP old/new effect (correctly recognized old items evoke more positive- going ERP waveforms than correctly identified new ones), which has been related to explicit memory (Rugg & Curran, 2007). Two temporally and spatially distinct ERP old/new effects have reliably been found over frontal (300–500 ms) Psychophysiology. 2018;e13069. https://doi.org/10.1111/psyp.13069 wileyonlinelibrary.com/journal/psyp V C 2018 Society for Psychophysiological Research | 1 of 12 Received: 26 January 2017 | Revised: 9 January 2018 | Accepted: 15 January 2018 DOI: 10.1111/psyp.13069