Shahin Hashtroudi

Aging and source monitoring.

This experiment was designed to examine the ability of older and younger adults to remember the source of information. Three types of source monitoring tasks were investigated: discriminating between externally derived and internally generated memories, discriminating between two types of internally generated memories, and discriminating between two types of externally derived memories. Relative to younger adults, older adults had more difficulty discriminating between memories of the same class (external-external and internal-internal), but they did not have more difficulty discriminating between memories of different classes (external-internal). These findings indicate that the age-related difficulty in remembering the source of information should not be characterized as a general deficit. Factors that may account for age deficits in source monitoring are discussed drawing upon the Johnson-Raye (1981) reality monitoring framework.

Age differences in using source-relevant cues.

Subjects heard words originating from 2 speakers and later decided which of the 2 speakers said the words. Older adults had difficulty with source monitoring when perceptual cues from 2 sources were similar (2 female speakers), but this difficulty was overcome when perceptual cues were distinctive (a male and a female speaker) and were the only salient cues to source. Older adults also benefited from distinctive spatial cues when these were the only salient cues to source. Older adults, however, experienced difficulties in using multiple cues (both perceptual and spatial) to source effectively, whereas younger adults were able to use multiple cues to enhance their source-monitoring performance. It is suggested that age differences in source monitoring result from differential cue utilization.

Does organization improve priming

In five experiments, the effects of organization on implicit memory or priming tests were compared with its effects on the explicit memory tests of free and cued recall. Organization was manipulated by varying list structure (blocked vs. random presentation of categorized items) and by instructions. The results showed that organization had parallel effects on the category-production priming test and free- and cued-recall tests; performance was enhanced by organization on both types of tests. It was also demonstrated that the effect of organization on priming was limited to the category-production test and was not obtained with the word-identification priming test. These results suggest that performance on implicit and explicit memory tests is similarly affected by experimental manipulations when both types of tests rely on conceptually driven processing. In addition, performance on two implicit tests is dissociated when one test relies on conceptually driven processing and the other on data-driven processing.

Intact Retention in Acute Alcohol Amnesia

Research on alcohol amnesia has focused on memory processes that are disrupted during intoxication. The present experiment examined the possibility that certain memory processes might be resistant to the amnesic effects of alcohol. Intoxicated and sober subjects studied a list of 29 words. They were then given one of three different retention tests: free recall, identification of degraded words based on the procedure used by Warrington and Weiskrantz (1970), and yes/no recognition. As expected, free recall was significantly impaired by alcohol intoxication. In contrast, in the identification test, intoxicated subjects benefited to the same degree as sober subjects from prior exposure to the items. The two groups did not differ in immediate recognition memory. The results of the free-recall and identification tasks are similar to findings with chronic amnesic patients and suggest that perceptual fluency is not affected by alcohol, whereas elaborative processes supporting recall are particularly sensitive to disruption during intoxication. The failure to find recognition impairment at the level of intoxication used in this study distinguishes temporary alcohol amnesia from chronic amnesia.

Effects of aging on priming and skill learning.

This study examined the effects of aging on 2 kinds of implicit memory; repetition priming and skill learning. In Experiment 1, older adults showed less improvement in the skill of reading inverted words than did young adults, but priming performance did not differ for the 2 age groups. Similarly, in Experiment 2, in a partial-word identification task, skill learning was observed only for young adults, whereas there was no age difference in priming. Experiments 1a and 2a, however, showed that when older adults were presented with more perceptual information than were young adults, the age deficit in skill learning was eliminated. These results indicate that skill learning is impaired under data-limited conditions, whereas priming is unaffected under these conditions. It is proposed that the age deficit in skill learning is related to a deficit in perceptual organization and reorganization.

On elaboration and alcohol

This study explored the effect of alcohol intoxication on elaborative processing and memory. Intoxicated and sober subjects were provided with “precise” or “imprecise” elaborators, or they generated their own elaborators. Precise elaborators facilitated recall for sober subjects but did not improve performance of intoxicated subjects. This deficiency in using precision was demonstrated with self-generated as well as experimenter-provided elaborators. Intoxicated subjects, however, did not generate more imprecise elaborators than sober subjects. The results suggest that alcohol intoxication does not disrupt activation of preexisting semantic structures, but it impedes the integration of incoming information with these structures.

Data-driven and conceptually driven processes in partial-word identification and recognition.

Three experiments examined priming in partial-word identification (Warrington & Weiskrantz, 1968) and its relation to recognition memory. The results showed that changes in modality of presentation between study and test reduced performance on both identification and recognition. In contrast, changes in elaborative processing enhanced recognition but had no effect on identification. Furthermore, when explicit memory instructions were given, identification was changed to a cued recall test and was consequently affected by elaborative processing. We also found that the time course of forgetting in priming was different from that in recognition; priming in identification did not change over a 24-hr interval, whereas recognition declined rapidly during this interval. Overall, these results suggest that identification relies primarily on data-driven processing, whereas recognition can rely on both data-driven and conceptually driven processing.

Priming is independent of skill learning.

This study examined the relation between repetition priming and skill learning. Priming refers to facilitation in processing a specific item as a result of previous exposure to that item. Skill learning refers to general improvement in task performance as a function of practice. In Experiment 1 (N = 60), skill acquisition occurred in partial-word identification and inverted reading tasks but not in a word-fragment completion task. However, the amount of priming was the same in all three tasks. In Experiment 2 (N = 52), priming effects in partial-word identification did not vary as a function of practice with degraded words. In Experiment 3 (N = 40), skill learning was greater with high- than with low-frequency words, whereas priming was unaffected by word frequency. Experiment 4 (N = 20) ruled out the possibility that explicit retrieval was involved in the implicit memory tasks. These results suggest that priming can be independent of skill learning.

The Effects of Milacemide on Item and Source Memory

Prior research has shown that memory for facts and items (item memory) and memory for where one has learned these items (source memory) can be dissociated under certain conditions. In this study, we examined the effects of milacemide, a derivative of glycine, on memory for item and source information in healthy young and older adults. These results pointed to a dissociation between source memory and item memory: Milacemide administration seemed to facilitate memory for source information but did not affect recognition memory.

Schema-Consistent and Schema-Inconsistent Information Processing Demands

Processing effort for schema-consistent, inconsistent, and neutral information was assessed by a secondary task technique. Schema-consistent and inconsistent information received similar processing effort, and both of these received greater effort than schema-irrelevant (neutral) information. These results suggest that the amount of cognitive effort in processing a sentence is dependent on the relevance of the sentence to a particular schema, and not on whether or not it fits the schema.