Two human studies have found that viewing early items in an encoding list are associated with greater low-frequency power decreases than viewing later items [81,82], and one of these studies also found that successful memory for earlier items is associated with greater low-frequency power decreases [81]. In other words, the successful encoding of early items is associated with stronger power decreases than the successful encoding of late items. Considered with the classic “primacy effect” finding that early list items are recalled more frequently -- perhaps due to an upregulation of attentional mechanisms -- this evidence further suggests that heightened attention is associated with low-frequency power decreases, in the setting of a memory task.
