Two experiments tested the hypothesis that it is easier to bind a stimulus to context when the stimulus already has a stable (i.e., pre-existing) memory representation by comparing episodic memory of faces of celebrities vs. unknown individuals. Each face was superimposed on a picture of a well-known location (e.g., Eiffel Tower) during encoding and at a later unexpected recognition test but the background could change from encoding to test. Although recognition was to be based on the face, irrespective of background, performance was better when encoding context was reinstated. Further, a given background could be shown with many faces ("high fan") or only a few ("low fan") and this variable modulated the value added of context reinstatement. Importantly, manipulations of context only mattered for famous faces. As predicted, these effects were observed in recollection ("Remember") responses not in familiarity (“Know”) responses. Experiment 2 used the same design except that half of the subjects were administered midazolam, a drug that produces temporary anterograde amnesia, prior to encoding faces and backgrounds. Subjects injected with saline (control condition) showed the same pattern as Experiment 1; however subjects injected with midazolam showed a large decrease in the use of the "Remember" responses for famous faces and neither context reinstatement nor background fan affected performance. These results support the view that it is easier to bind stimuli to context when stimuli have a pre-existing, stable memory representation (e.g., faces of people whose identity we know) than when stimuli do not have pre-existing, stable memory representations.

Midazolam is a drug that creates temporary anterograde amnesia. In a within-subjects, doubleblind experiment, participants studied a list of stimuli after receiving an injection of midazolam in one session and after receiving saline in another session. The lists consisted of three types of stimuli: words, photographs, and abstract pictures. Recognition memory was tested at the end of each session. Memory was reliably poorer in the midazolam condition than the saline condition, but this amnesic effect was significantly smaller for pictorial stimuli than for words and almost nonexistent for abstract pictures. We argue that the less familiar the stimulus, the less likely it is to be associated with an experimental context. These data bolster our claim that unitization increases the chances of episodic binding and that drug-induced amnesia prevents episodic binding regardless of unitization.There is evidence that recognition can be based on either the retrieval of episodic information or the backup process of familiarity (Diana,

Individuals with Williams syndrome (WS) often experience significant anxiety. A promising approach to anxiety intervention has emerged from cognitive studies of attention bias to threat. To investigate the utility of this intervention in WS, this study examined attention bias to happy and angry faces in individuals with WS (N=46). Results showed a significant difference in attention bias patterns as a function of IQ and anxiety. Individuals with higher IQ or higher anxiety showed a significant bias toward angry, but not happy faces, whereas individuals with lower IQ or lower anxiety showed the opposite pattern. These results suggest that attention bias interventions to modify a threat bias may be most effectively targeted to anxious individuals with WS with relatively high IQ.

In a double-blind, placebo-controlled experiment that used midazolam, a benzodiazepine that creates temporary amnesia, we compared acquisition and retention of paired associates of different types. Some word pairs were studied before the injection of saline or midazolam, and two lists of word pairs were studied after the injection. Critical comparisons involved retention of pairs that were practiced on all three lists, pairs studied on only one list, and pairs that involved recombining cue and response terms from one list to the next, as a function of drug condition. Previous research with benzodiazepines had found retrograde facilitation for material acquired prior to injection, compared with the control condition. One explanation for this facilitation is that the anterograde amnesia produced by the benzodiazepine frees up the hippocampus to better consolidate previously learned material (Wixted, 2004(Wixted, , 2005. We accounted for a rich data set using a simple computational model that incorporated interference effects (cue overload) at retrieval for both general (experimental context) interference and specific (stimulus term) interference without the need to postulate a role for consolidation. The computational model as an Excel spreadsheet may be downloaded from www.psychonomic.org/archive.Psychologists have long investigated the class of mechanisms that affect retention of past experience. Wixted (2004Wixted ( , 2005 notes that psychologists have ignored the role of consolidation while debating the role of interference and decay as mechanisms of forgetting. He reviews evidence from psychology, psychopharmacology, and neuroscience to argue that the traditional psychological theories of forgetting "may not be relevant to the kind of interference that induces most forgetting in everyday life" (p.6). Wixted reviews evidence from Correspondence concerning this article should be addressed to L. M. Reder, Psychology Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (e-mail: reder@cmu.edu). Archived MaterialsThe following materials [and links] associated with this article may be accessed through the Psychonomic Society's Norms, Stimuli, and Data archive, www.psychonomic.org/archive. To access these files [or links], search the archive for this article using the journal name (Psychonomic Bulletin & Review), the first author's name (Reder), and the publication year (2007 psychopharmacology to support the claim that general interference or "mental exertion" is a major determinant in whether information is forgotten. In particular he notes that benzodiazepines, which produce amnesia for material learned after the drug, create retrograde facilitation for material learned before the drug. He argues that this results from the absence of mental exertion. This article reports a new study designed to understand the mechanisms that underlie the retrograde facilitation observed under the influence of benzodiazepines.Studies using benzodiazepines, such as diazepam (Valium) and alprazolam...

Rationale-Although there have been many studies examining the effects of benzodiazepines on memory performance, their effects on working memory are equivocal and little is known about whether they affect the efficacy of practice of already learned material.Objectives-The objectives in two experiments were to examine (a) whether midazolam impairs performance on a working memory task designed to minimize mnemonic strategies such as rehearsal or chunking of information to be recalled and (b) the effect of midazolam on repeated practice of paired associates that were learned before drug administration.Materials and methods-Both experiments involved subcutaneous administration of 0.03 mg/ kg of body weight of saline or midazolam in within-subject, placebo-controlled designs, involving 23 subjects in (a) and 31 in (b).Results-The drug had no effect on the ability to recall the digits in serial order even though the encoding task prevented the digits from being rehearsed or maintained in an articulatory buffer. Paired associates that were learned before the injection showed a benefit of subsequent practice under saline but not under midazolam. Conclusions-The results suggest that (a) midazolam does not affect the formation of new associations in short-term memory (STM) provided that the presentation rate is not too fast to form these associations when sedated, despite the evidence that the drug blocks long-term memory (LTM) retention of associations; and (b) the potential for over-learning with practice of learned associations in LTM is adversely affected by midazolam such that repeated exposures do not strengthen new learning. KeywordsBenzodiazepine; Working memory; Memory; Binding; Paired associate learning; Practice; MODS task; Midazolam; Over-learning; Digit span Researchers concerned with understanding human memory have sometimes relied on studies of patients with anterograde amnesia to provide insights and constraints on theories of memory mechanisms (Milner 2005). Although this research on patients with amnesia can use accidents