Epoch construction

We partitioned encoding or retrieval trials into two event classes. During the encoding of a list, we defined successful memory events as words that were subsequently recalled within the corresponding recall period of the list, and unsuccessful memory events as words that were not recalled. During retrieval, we defined successful memory events as the memory search intervals immediately preceding recalls of list items (correct recalls). Unsuccessful memory search periods preceded recall errors, including recall of words from previous lists (prior-list intrusions, PLIs) and from outside of the word pool (extra-list intrusions, ELIs). To minimize speech artifacts, we excluded recall responses which began within 1 s after the onset of the previous recall. For the encoding events, we averaged the spectral patterns from 250 ms to 1350 ms after word onset, effectively covering the 0–1600 ms presentation window. For memory search intervals in the free recall phases, we extracted the spectral patterns at 250 ms prior to speech onset, effectively covering a 500 ms memory search window before the observed onset of recall responses.