The impact of increasing similar interfering experiences on mnemonic discrimination: Electrophysiological evidence.

The accumulation of similar interfering experiences hampers our ability to retrieve information. To reduce interference, pattern separation allows the separation of similar memories and build detailed memory representations that are less easily confused. To investigate mnemonic interference, previous research has used a mnemonic discrimination paradigm in which the participants have to mnemonically discriminate between two similar items. Unique from previous studies, electrophysiological brain activity was recorded while 26 healthy participants performed a visual mnemonic discrimination task in which we parametrically manipulated the number of studied exemplars from each category. According to our expectations, as the number of exemplars from the same object category increased, participants were less able to discriminate between old and similar presented items. A 'parietal' old/new effect in a temporal window associated with recollection was observed when interference was higher. Increasing the number of exemplars presented also modulated the ERP amplitude in a temporal window associated with familiarity.