Interpolated retrieval retroactively increases recall and promotes cross-episode memory interdependence

Abstract

Retrieving existing memories before new learning can lead to retroactive facilitation. Three experiments examined whether interpolated retrieval is associated with retroactive facilitation and memory interdependence that reflects integrative encoding. Participants studied two lists of cue-response word pairs that repeated across lists (A-B, A-B), appeared in list 1 (A-B, -), or included the same cues with changed responses in each list (A-B, A-C). For A-B, A-C pairs, the tasks interpolated between lists required recall of list 1 (B) responses (with or without feedback) or restudy of complete list 1 (A-B) pairs. In list 2, participants only studied pairs (experiment 1) or studied pairs, attempted to detect changed (C) responses, and attempted to recall list 1 responses for detected changes (experiments 2 and 3). On a final cued recall test, participants attempted to recall list 1 responses, indicated whether responses changed between lists, and if so, attempted to recall list 2 responses. Interpolated retrieval was associated with subsequent retroactive facilitation and greater memory interdependence for B and C responses. These correlational findings are compatible with the view that retrieval retroactively facilitates memories, promotes coactivation of existing memories and new learning, and enables integrative encoding that veridically binds information across episodes.

Figure 1.

Schematics illustrating manipulations across conditions (A) and trial structures across all phases using examples of A–B, A–C item types (B). (A) Experiments 1 and 2 included five conditions, and experiment 3 included four conditions comprising combinations of varying relationships between cue–response word pairs in each list and tasks interpolated between lists. (B) During list 1, participants read aloud and studied word pairs. During the interpolated phase, participants restudied A–B pairs and attempted to retrieve B responses from other A–B pairs with or without feedback. During list 2, participants read aloud and studied word pairs (experiment 1) or studied word pairs, indicated whether responses changed from list 1, and if so, attempted to recall list 1 responses (experiments 2 and 3). On the final test, participants attempted to recall list 1 responses, indicated whether responses changed between lists, and if so, attempted to recall list 2 responses.

Figure 2.

List 1 recall on interpolated tests (A) and in list 2 (B). The interpolated task labels on the X-axis of each panel indicate what happened with A–B pairs in the interpolated phase before participants learned A–C pairs in list 2. The interpolated tasks comprised cued recall tests of B responses without feedback (A–B test, no feedback) or with feedback (A–B test, feedback), and restudy of complete A–B pairs (A–B restudy). The item type coloring indicates whether pairs appeared in an A–B, A–C condition that included the same cues (A) in each list and different responses in list 1 (B) and list 2 (C) or in an A–B, — condition that included list 1 A–B pairs that did not correspond to any list 2 pairs. The colored points are marginal means estimated from mixed-effect models, and error bars are the corresponding 95% confidence intervals. The gray points are individual participant probabilities.

Figure 3.

Correct list 1 recall (A), intrusions from list 2 (B), and correct list 2 recall (C) on the final test. The interpolated task labels on the X-axis of each panel indicate what happened with A–B pairs in the interpolated phase before participants learned A–C pairs in list 2. The interpolated tasks comprised cued recall tests of B responses without feedback (A–B test, no feedback), restudy of complete A–B pairs (A–B restudy), and cued recall tests of B responses with feedback (A–B test, feedback). The item type coloring indicates whether pairs appeared in an A–B, A–B condition that included the same cues (A) and responses (B) in lists 1 and 2; in an A–B, — condition that included list 1 A–B pairs that did not correspond to any list 2 pairs; or in an A–B, A–C condition that included the same cues (A) in each list and different responses in list 1 (B) and list 2 (C). Note that all C responses produced in the A–B, A–B and A–B, — conditions are extraexperimental intrusions. Those C response probabilities in B and C therefore show baseline estimates of participants guessing what would have been C responses for those items had they appeared in an A–B, A–C condition. The colored points are marginal means estimated from mixed-effect models, and error bars are the corresponding 95% confidence intervals. The gray points are individual participant probabilities.

Figure 4.

Final test list 1 recall conditioned on list 2 recall for A–B, A–C item types for which the interpolated tasks included tests of A–B pairs. The interpolated task labels on the X-axis of each panel indicate what happened with A–B pairs in the interpolated phase before participants learned A–C pairs in list 2. The probabilities for “conditional” items were conditioned on whether the C response was recalled correctly. The point heights are the marginal means estimated from mixed-effect models, and error bars are 95% confidence intervals. The conditional point sizes indicate observation differences.

Figure 5.

Final test list 1 recall, conditioned on recall in the interpolated phase and list 2. The interpolated task labels on the X-axis of each panel indicate what happened with A–B pairs in the interpolated phase before participants learned A–C pairs in list 2. The probabilities for “conditional” items were conditioned on whether the B response was recalled during the interpolated phase (interrecall) and whether the C response was recalled correctly (C recall) following correct interpolated B response recall. The point heights are the marginal means estimated from mixed-effect models, and error bars are 95% confidence intervals. The conditional point sizes indicate observation differences.

Figure 6.

List 1 recall on list 2, conditioned on recall during the interpolated phase for A–B, A–C item types. The interpolated task labels on the X-axis of each panel indicate what happened with A–B pairs in the interpolated phase before participants learned A–C pairs in list 2. The probabilities for items labeled “conditional” were conditioned on whether the B response was recalled during the interpolated phase. The point heights are the marginal means estimated from mixed-effect models, and error bars are 95% confidence intervals. The conditional point sizes indicate observation differences.