![]() ![]() The attention required to parse such stimuli consumes the resources that otherwise would bind a stimulus to context. In contrast, unfamiliar abstract pictures are difficult to encode, having no stored memory representation. We predicted that memory for words would be hurt most by the drug because normally they can be easily bound to context. We chose to use abstract drawings, photographs of faces and outdoor scenes, and words. (1999) used words, nonwords, and random shapes in their priming task. ![]() To the degree that a subject cannot create a binding to a stimulus under normal circumstances, the impact of midazolam should be minimized. The present experiment was designed to investigate whether stimuli that are especially unfamiliar would show a reduced effect from a drug that creates temporary amnesia. Therefore, we expect that to the degree that stimuli are too difficult to bind to an episodic node and are recognized on the basis of familiarity, recognition performance will be unaffected by a psychopharmacological intervention that produces temporary amnesia. Previous research using midazolam has supported the results found with amnesic patients: Familiarity judgments are unaffected by amnesia, but ability to form new associations is impaired whether or not the amnesia is drug induced ( Hirshman et al., 2002 Huppert & Piercy, 1976, 1978). We believe that ease of encoding affects ease of binding. For example, lexical decision and word naming are faster for high-frequency than low-frequency words ( Balota & Chumbley, 1984). Conversely, the more familiar a stimulus, the easier it is to encode. We propose that the less familiar a stimulus is, the more difficult it is to encode and, as a consequence, the more difficult it is to bind to an episodic trace or to another stimulus. Although the patients could recognize low-frequency words and pictures on the basis of the familiarity process, they could not discriminate whether those stimuli were seen the day before or 10 min before the test. The amnesiacs in Huppert and Piercy's (1976, 1978) experiments were successful in recognition because the stimuli were not high in preexperimental familiarity and therefore not vulnerable to spurious recognition. (2000, 2002) suggested that recognition judgments can be based on retrieval of episodic traces or on familiarity, they also claimed that stimuli with greater preexperimental familiarity are more vulnerable to spurious “old” judgments arising from the familiarity process. Therefore, we hypothesize that unfamiliar stimuli are also at a disadvantage when it comes to recollection.Īlthough Reder et al. This impairment in the process of binding stimuli to contexts has implications for recollection (see Reder et al., 2002). We believe that just as people are unable to associate very unfamiliar stimuli with colors, they are unable to bind unfamiliar stimuli to contexts (i.e., to form episodic links). The authors concluded that only words could be associated with the colors. Nonwords and random shapes did not provide an analogous facilitation. Recently Musen, Szerlip, and Szerlip (1999) found evidence of priming in color naming when words studied earlier with the colors were reinstated. (2002) found that subjects under the influence of midazolam, a benzodiazepine that causes transient anterograde amnesia, produce more hits and false alarms to high-frequency items than to low-frequency items this result is consistent with the view that the drug blocks the formation of an episodic trace. This suggests that the temporal (contextual) information was not associated with the stimuli and that the judgments are based only on familiarity ( Balota, Burgess, Cortese, & Adams, 2002 Balota & Ferraro, 1996 Reder et al., 2000, 2002). ![]() However, these patients cannot determine whether the words and pictures were just studied or studied a day earlier. When stimuli that have a high degree of preexperimental familiarity are not included among the experimental stimuli, amnesic patients are able to discriminate recently experienced (studied) words and pictures from foils (words and pictures that were not studied in the experiment Huppert & Piercy, 1976). Research with amnesic patients ( Huppert & Piercy, 1976, 1978 Piercy & Huppert, 1972) and with normal subjects under the influence of a drug that produces temporary amnesia suggests that the recollective process but not the familiarity-based process is specifically vulnerable to anterograde amnesia ( Hirshman, Fisher, Henthorn, Arndt, & Passannante, 2002 Mintzer, 2003). There is evidence that recognition can be based on either the retrieval of episodic information or the backup process of familiarity ( Diana, Reder, Arndt, & Park, 2006 Jacoby, 1991 Jacoby & Dallas, 1981 Joordens & Hockley, 2000 Mandler, 1980 Reder, Angstadt, Cary, Erickson, & Ayers, 2002 Reder et al., 2000 Yonelinas, 1994, 1999).
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