While asleep, people heard sounds that had earlier been associated with objects at specific spatial locations. Upon waking, they recalled these locations more accurately than other locations for which no reminder cues were provided. Consolidation thus operates during sleep with high specificity and is subject to systematic influences through simple auditory stimulation.Initially fragile memories can gain stability via consolidation, but the extent to which sleep contributes to this process is unresolved (1,2). Sleep between encoding and retrieval, relative to wakefulness, promotes memory storage in some circumstances, perhaps from internally generated memory reactivation (3,4). Moreover, reinstating a learning context (an odor) during slow-wave sleep enhances retrieval of spatial information learned in that context (5). It remains unclear whether exposure during sleep to cues associated with newly learned information can selectively enhance the storage of individual memories.We taught people to associate each of 50 unique object images with a location on a computer screen prior to a nap (Fig. 1A). Each object was paired with a characteristic sound delivered over a speaker (e.g., cat/meow, kettle/whistle). For the entirety of the nap, white noise was presented at an unobtrusive intensity (~62dB sound-pressure level), and during non-REM sleep the sounds for 25 of the objects were presented, with white-noise intensity lowered so that overall levels were approximately constant (Fig. 1B).After waking, individuals viewed all 50 objects and attempted to position each one in its original location. Absolute distance measures showed that object placements were more accurate for objects that were cued by their sounds during sleep than for those not cued (1.07 cm ± 0.08 SE vs. 1.23 cm ± 0.10 SE, respectively, t 11 = 2.6, p < .05). Forgetting occurred between the final stage of learning and the post-nap test, with a smaller decline for cued compared to uncued objects (Fig. 1C). An advantage for cued-object locations computed in this manner was evident in 10 of the 12 participants.EEG recordings provided information for determining sleep stages (6). Additionally, EEG responses to sound cues were sorted into 2 conditions via a median split on the difference between pre-and post-nap accuracy: (1) in the less-forgetting condition, mean accuracy was superior post-nap (placements 0.51 cm ± 0.1 cm SE closer to correct); (2) in the moreforgetting condition, mean accuracy was superior pre-nap (placements 0.60 cm ± 0.1 cm SE farther from correct). Average EEG amplitudes measured over the interval from 600-1000 ms after sound onset were 15.3 μV greater when there was less forgetting (t 11 = 3.2, p < .

Decisions about whether to trust someone can be influenced by competing sources of information, such as analysis of facial features versus remembering specific information about the person. We hypothesized that such sources can differentially influence trustworthiness judgments depending on the circumstances in which judgments are made. In our experiments, subjects first learned face-word associations. Stimuli were trustworthy and untrustworthy faces, selected on the basis of consensus judgments, and personality attributes that carried either the same valence (consistent with face) or the opposite valence (inconsistent with face). Subsequently, subjects rated the trustworthiness of each face. Both learned and perceptual information influenced ratings, but learned information was less influential under speeded than under non-speeded conditions. EEG data further revealed neural evidence of the processing of these two competing sources. Perceptual influences were apparent earlier than memory influences, substantiating the conclusion that time pressure can selectively disrupt memory retrieval relevant to trustworthiness attributions.

Determining whether patients with amnesia can succeed in remembering their distant past has pivotal implications for theories of memory storage. However, various factors influence recall. We speculated that some patients with anterograde amnesia adopt a gist-based retrieval orientation for memories from all time periods, thereby exaggerating remote recall deficits. We tested whether an experimentally induced gist-based retrieval orientation could indeed hinder remote recall. Healthy individuals described photographs of complex scenes (e.g., of a cluttered desk) either with many words or few words (detail-or gist-based manipulation, respectively). They subsequently recalled autobiographical events and produced less episodic information after engaging the gist-based compared to the detail-based orientation. These results demonstrate the ease with which a gist-based orientation can produce apparent recall impairments. Deficits in remote episodic recall, and in futureevent imagining, must thus be interpreted in light of habitual tendencies toward gist-based retrieval that some amnesic patients may exhibit.