Exploring the relationship between retrieval disruption from collaboration and recall

When people recall together in a collaborative group they recall less than their potential. This phenomenon of collaborative inhibition is explained in terms of retrieval disruption. However, collaborative recall also re-exposes individuals to items recalled by others that they themselves might otherwise have forgotten. This re-exposure produces post-collaborative benefits in individual recall. The current study examined whether reduced retrieval disruption during group recall is related not only to less collaborative inhibition, but also to greater post-collaborative recall benefits. To test this we devised a paradigm to calculate the extent to which each individual experienced retrieval disruption during group recall. We also included two types of collaborative groups, one of which was expected to experience greater retrieval disruption than the other. Results suggest that the relationship between retrieval disruption and recall performance depends on the level at which retrieval disruption is measured. When retrieval disruption was assessed at the individual level, then minimising retrieval disruption was associated with higher recall (i.e., less collaborative inhibition and greater post-collaborative individual recall). However, when retrieval disruption was assessed at the group level there was no relationship with recall. Furthermore, the findings from this design suggest a role of cross-cueing in modulating group recall levels.     

Memory for dangers past: threat contexts produce more consistent learning than do non-threatening contexts

In earlier work we showed that individuals learn the spatial regularities within contexts and use this knowledge to guide detection of threatening targets embedded in these contexts. While it is highly adaptive for humans to use contextual learning to detect threats, it is equally adaptive for individuals to flexibly readjust behaviour when contexts once associated with threatening stimuli begin to be associated with benign stimuli, and vice versa. Here, we presented face targets varying in salience (threatening or non-threatening) in new or old spatial configurations (contexts) and changed the target salience (threatening to non-threatening and vice versa) halfway through the experiment to examine if contextual learning changes with the change in target salience. Detection of threatening targets was faster in old than new configurations and this learning persisted even after the target changed to non-threatening. However, the same pattern was not seen when the targets changed from non-threatening to threatening. Overall, our findings show that threat detection is driven not only by stimulus properties as theorised traditionally but also by the learning of contexts in which threatening stimuli appear, highlighting the importance of top-down factors in threat detection. Further, learning of contexts associated with threatening targets is robust and speeds detection of non-threatening targets subsequently presented in the same context.     

The effects of attention on perceptual implicit memory

Reports on the effects of dividing attention at study on subsequent perceptual priming suggest that perceptual priming is generally unaffected by attentional manipulations as long as word identity is processed. We tested this hypothesis in three experiments by using the implicit word fragment completion and word stem completion tasks. Division of attention was instantiated with the Stroop task in order to ensure the processing of word identity even when the participant's attention was directed to a stimulus attribute other than the word itself. Under these conditions, we found that even though perceptual priming was significant, it was significantly reduced in magnitude. A stem cued recall test in Experiment 2 confirmed a more deleterious effect of divided attention on explicit memory. Taken together, our findings delineate the relative contributions of perceptual analysis and attentional processes in mediating perceptual priming on two ubiquitously used tasks of word fragment completion and word stem completion.     

When two is too many: Collaborative encoding impairs memory

Humans routinely encode and retrieve experiences in interactive, collaborative contexts. Yet much of what we know about human memory comes from research on individuals working in isolation. Some recent research has examined collaboration during retrieval, but not much is known about how collaboration during encoding affects memory. We examined this issue. Participants created episodes by elaborating on study materials alone or collaboratively, and they later performed a cued-recall task alone, with the study partner, or with a different partner (Experiment 1). Collaborative encoding impaired recall. This counterintuitive outcome was found for both individual and group recall, even when the same partners collaborated across encoding and retrieval. This impairment was significantly reduced, but persisted, when the encoding instructions encouraged free-flowing collaboration (Experiment 2). Thus, the collaborative-encoding deficit is robust in nature and likely occurs because collaborative encoding produces less effective cues for later retrieval.     

Effects of repeated collaborative retrieval on individual memory vary as a function of recall versus recognition tasks

Our research examines how prior group collaboration modulates later individual memory. We recently showed that repeated collaborative recall sessions benefit later individual recall more than a single collaborative recall session (Blumen & Rajaram, 2008). Current research compared the effects of repeated collaborative recall and repeated collaborative recognition on later individual recall and later individual recognition. A total of 192 participants studied a list of nouns and then completed three successive retrieval sessions in one of four conditions. While two collaborative recall sessions and two collaborative recognition sessions generated comparable levels of individual recall (CRecall-CRecall-I Recall ～ CRecognition-CRecognition-I Recall , Experiment 1a), two collaborative recognition sessions generated greater levels of individual recognition than two collaborative recall sessions (CRecognition-CRecognition- IRecognition > CRecall-CRecall- I Recognition , Experiment 1b). These findings are discussed in terms of two opposing mechanisms that operate during collaborative retrieval—re-exposure and retrieval disruption—and in terms of transfer-appropriate processing across collaborative and individual retrieval sessions.     

Collaborative memory and part-set cueing impairments: The role of executive depletion in modulating retrieval disruption

When people are exposed to a subset of previously studied list items they recall fewer of the remaining items compared to a condition where none of the studied items is provided during recall. This occurs both when the subset of items is provided by the experimenter (i.e., the part-set cueing deficit in individual recall) and when they are provided during the course of a collaborative discussion (i.e., the collaborative inhibition effect in group recall). Previous research has identified retrieval disruption as a common mechanism underlying both effects; however, less is known about the factors that may make individuals susceptible to such retrieval disruption. In the current studies we tested one candidate factor: executive control. Using an executive depletion paradigm we directly manipulated an individual's level of executive control during retrieval. Results revealed no direct role of executive depletion in modulating retrieval disruption. In contrast, executive control abilities were indirectly related to retrieval disruption through their influence at encoding. Together these results suggest that executive control des not directly affect retrieval disruption at the retrieval stage, and that the role of this putative mechanism may be limited to the encoding stage.     

Distinguishing states of awareness from confidence during retrieval: evidence from amnesia

Two experiments were conducted to determine whether recollective experience is distinguishable from confidence. In Experiment 1, we tested college participants in a within-subjects design and replicated Gardiner and Java's (1990) findings from a between-subjects design. We observed higher remember judgments for words than for nonwords, but higher know judgments for nonwords than for words. For confidence judgments, we obtained greater sure than unsure responses for both words and nonwords. In Experiment 2, we tested amnesic participants and matched control participants. Control participants produced the same pattern of results as college participants, but the results of amnesic participants diverged in an important way. For confidence judgments, the amnesic participants, like the control and college participants, made more sure than unsure judgments to both words and nonwords. But for recollective judgments, amnesic participants did not produce the crossover interaction for words and nonwords. This striking difference between the performance of memory-intact and amnesic participants demonstrates that recollective judgments and confidence that accompany retrieval are not isomorphic psychological experiences.