State-dependent recall decrements with moderate doses of alcohol

Thirty-two adult volunteers were asked to memorize a simplified geographical map, visually displayed, together with an auditorially presented 19-item set of instructions regarding a particular route. During this session, half the subjects were sober and half were under the effects of a moderate dose of alcohol (mean blood alcohol concentration = 81mg/100ml). Twenty-four hours later they were tested under the same or different conditions. Learning performance on Day 1 was unaffected by alcohol. Learning transfer (tested on Day 2) was equally good when subjects were intoxicated during both sessions or were sober during both sessions. There were significant decrements in recall on Day 2, when subjects were in a different drug state. This ‘dissociation of learning’ was found to be symmetrical in that the recall decrement was the same whether the initial learning was acquired in a sober or a drugged state.     

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.     

Influence of marihuana on storage and retrieval processe in memory

Following presentation and immediate free recall testing of 10 20-word lists, 48 Ss were divided into two groups, one of which received an oral dose of marihuana extract calibrated to 20 mg of Δ¹-THC and one of which received placebo. One hour later, all Ss were administered delayed recall, recognition, and order tests on the first set of words. Presentation of another set of 10 lists followed, and there were immediate recall and delayed recall, recognition, and order tests on these words. Performance of drug and placebo Ss did not differ significantly for any of the first delayed tests. However, the performance of drug Ss was poorer than that of placebo Ss on immediate recall, delayed recall, and delayed recognition of the second set of lists. We concluded that retrieval of information relevant to the occurrence or nonocurrence of an event was not affected by marihuana intoxication. Storage difficulties probably account for memory deficits due to the drug, and these difficulties appear to occur in the process of transferring information from short-term to long-term memory.     

Recency and suffix effects with immediate recall of olfactory stimuli

In contrast to our understanding of the immediate recall of auditory and visual material, little is known about the corresponding characteristics of short-term olfactory memory. The current study investigated the pattern of immediate serial recall and the associated suffix effect using olfactory stimuli. Subjects were trained initially to identify and name correctly nine different odours. Experiment 1 established an immediate correct recall span of approximately six items. In Experiment 2 participants recalled serially span equivalent lists which were followed by a visual, auditory, or olfactory suffix. Primacy was evident in the recall curves for all three suffix conditions. Recency, in contrast, was evident in the auditory and visual suffix conditions only; there was a strong suffix effect in the olfactory suffix condition. Experiment 3 replicated this pattern of effects using seven-item lists, and demonstrated that the magnitude of the recency and suffix effects obtained in the olfactory modality can equate to that obtained in the auditory modality. It is concluded that the pattern of recency and suffix effects in the olfactory modality is reliable, and poses difficulties for those theories that rely on the presence of a primary linguistic code, sound, or changing state as determinants of these effects in serial recall.     

Examining the relationship between free recall and immediate serial recall: Similar patterns of rehearsal and similar effects of word length,presentation rate,and articulatory suppression

In five experiments, rehearsal and recall phenomena were examined using the free recall and immediate serial recall (ISR) tasks. In Experiment 1, participants were presented with lists of eight words, were precued or postcued to respond using free recall or ISR, and rehearsed out loud during presentation. The patterns of rehearsal were similar in all the conditions, and there was little difference between recall in the precued and postcued conditions. In Experiment 2, both free recall and ISR were sensitive to word length and presentation rate and showed similar patterns of rehearsal. In Experiment 3, both tasks were sensitive to word length and articulatory suppression. The word length effects generalized to 6-item (Experiment 4) and 12-item (Experiment 5) lists. These findings suggest that the two tasks are underpinned by highly similar rehearsal and recall processes.     

Recency and suffix effects with immediate recall of olfactory stimuli

In contrast to our understanding of the immediate recall of auditory and visual material, little is known about the corresponding characteristics of short-term olfactory memory. The current study investigated the pattern of immediate serial recall and the associated suffix effect using olfactory stimuli. Subjects were trained initially to identify and name correctly nine different odours. Experiment 1 established an immediate correct recall span of approximately six items. In Experiment 2 participants recalled serially span equivalent lists which were followed by a visual, auditory, or olfactory suffix. Primacy was evident in the recall curves for all three suffix conditions. Recency, in contrast, was evident in the auditory and visual suffix conditions only; there was a strong suffix effect in the olfactory suffix condition. Experiment 3 replicated this pattern of effects using seven-item lists, and demonstrated that the magnitude of the recency and suffix effects obtained in the olfactory modality can equate to that obtained in the auditory modality. It is concluded that the pattern of recency and suffix effects in the olfactory modality is reliable, and poses difficulties for those theories that rely on the presence of a primary linguistic code, sound, or changing state as determinants of these effects in serial recall.     

Right-ear advantage and delayed recall

Two studies were performed using monaural presentation of verbal material to test for a right-ear advantage (REA) in recall. It was hypothesized that a delayed recall task and examination of the serial position curve would be a more sensitive test for ear asymmetries than those used in previous studies. In Experiment 1, 30 right-handed male subjects were given lists of words to recall, presented to either the left or right ear, with language chatter, baroque music, or no stimulus concurrently presented to the opposite ear. Both immediate and delayed recall were assessed. The results indicated that the strongest REAs appeared in delayed recall. Moreover, the REAs occurred regardless of the stimulus conditions co-occurring in the other ear. Experiment 2 was done to test whether the REAs in the delayed recall were due to rehearsal biases. Twenty-four right-handed male subjects recalled lists of words with standard instructions and instructions to recall in the reverse order of input (limiting rehearsal). The results indicated that the backward instructions limited and controlled rehearsal and, hence, input to long-term storage; the REAs occurred in delayed recall under all instructional conditions.     

Memory for Related and Unrelated Words: Further Evidence on the Influence of Semantic Factors in Immediate Serial Recall

A number of recent studies have explored the role of long-term memory factors in memory span tasks. The effects of lexicality, frequency, imageability, and word class have been investigated. The work reported in this paper examined the effect of semantic organization on the recall of short lists of words. Specifically, the influence of semantic category on immediate serial recall and the interaction of this variable with articulatory suppression was investigated in three experiments. Experiment 1 compared immediate serial recall performance when lists comprising items from the same semantic category were used (homogeneous condition) with a situation where lists held items from different semantic categories. Experiment 2 examined the same conditions with and without articulatory suppression during item presentation, and Experiment 3 reproduced these conditions with suppression occurring throughout presentation and recall. Results of all three experiments showed a clear advantage for the homogeneous condition. Experiments 2 and 3 showed that the homogeneous category advantage did not depend on the articulatory loop. Furthermore, error analysis indicated that this effect was mainly attributable to better item information recall for the homogeneous condition. These results are interpreted as reflecting a long-term memory contribution to the recall stage of immediate serial recall tasks.     

An auditory repetition deficit under low memory load

Previous studies of the auditory analogue of repetition blindness have led to different conclusions regarding the nature of the effect (e.g., N. Kanwisher & M. C. Potter, 1989; M. Miller & D. MacKay, 1994). In the present study, recall accuracy for repeated elements was examined with lists of 2 or 3 items presented dichotically under high temporal pressure. When this procedure was used, a repetition deficit in recall was obtained for both vowels (Experiment 1) and consonant-vowel syllables (Experiment 2). Further experiments demonstrated that this deficit decreases as the stimulus onset asynchrony between the 2 critical elements increases (Experiment 3) and showed that the effect also occurs for words and not just nonsense syllables (Experiment 4). In all 4 experiments, estimations of guessing biases showed that responses to unrepeated lists were not artificially favored over responses to repeated lists.     

Alcohol-induced state-dependent learning: Differentiating stimulus and storage hypotheses

State-dependent effects of alcohol have been demonstrated in animals and man. Most studies have used tasks for which accurate performance typically requires that stimulus input was adequately stored initially and that the items were retrieved at the time of testing. Thus an alcohol-induced decrement in performance could be due to impaired storage, impaired retrieval, or both. The purpose of this experiment was to distinguish between stimulus and storage hypotheses of state-dependent learning (SDL). Sixteen subjects were used in a 2×2 design in which the task involved the learning and recall of a 19-item ‘route’ map. During initial learning, all subjects were sober. Immediately after learning, half the subjects were given a moderate dose of alcohol. Twenty-four hours later, all subjects were tested for recall under the same or different conditions. Greater retention was found for those subjects whose drug states were the same in memory storage/consolidation and retrieval. Thus an alcohol state effective during the memory consolidation interval following acquisition appears to be a sufficient condition for producing SDL. In this context, SDL might be better termed state-dependent memory storage and retrieval. The implications of these results for the aetiology and treatment of alcohol dependence are discussed.     

Interviewing intoxicated witnesses: Memory performance in theory and practice

Memory encoding and recall involving complex, effortful cognitive processes are impaired by alcohol primarily due to impairment of a select few, but crucial, cortical areas. This review shows how alcohol affects some, but not all, aspects of eyewitnesses' oral free recall performance. The principal results, so far, are that: a) free recall reports by intoxicated witnesses (at the investigated BAC‐levels) may contain less, but as accurate, information as reports by sober witnesses; b) immediate reports given by intoxicated witnesses may yield more information compared to reports by sober witnesses given after a one week delay; c) an immediate interview may enhance both intoxicated and sober witnesses' ability to report information in a later interview; and d) reminiscence seems to occur over repeated interviews and the new information seems to be as accurate as the previously reported information. Based on this, recommendations are given for future research to enhance understanding of the multifaceted impact of alcohol on witnesses' oral free recall of violent crimes.     

Witnesses stumbling down memory lane: The effects of alcohol intoxication,retention interval,and repeated interviewing

Intoxicated eyewitnesses are often discredited by investigators and in court, but few studies have examined how alcohol affects witnesses’ memory. The primary aim of the present study was to examine how intoxication (alcohol vs. control), retention interval (immediate vs. one week delay), and number of interviews (one vs. two interviews) affect witnesses’ memory. The participants (N?=?99) were randomly assigned to consume either orange juice or alcohol mixed with orange juice, and they all witnessed a filmed mock crime afterwards. The recall took place either (a) immediately and after a one week delay or (b) after a one week delay only. No main effect of alcohol was found on the quantity or quality of the witnesses’ statements. Both intoxicated and sober witnesses recalled more details, and were more accurate, during immediate compared to delayed recall. For witnesses interviewed twice, an average of 30% new details were provided in the second compared to the first interview, and these were highly accurate. In sum, contrary to what one can expect, intoxicated witnesses with a low to moderate blood alcohol concentration (below 0.10%) were reliable witnesses.     

Can intentional forgetting reduce false memory? Effects of list-level and item-level forgetting

This study examined whether false memory produced by the learning of lists of categorized and associative materials could be reduced by directed forgetting. The number of items within a list that participants were asked to remember or forget was manipulated, while the length of the list remained constant. Experiment 1a used categorized lists and Experiment 1b used associative lists; the participants performed immediate free recall and cued recall tests. For both the categorized and associative lists, the rate of false recall increased upon increasing the proportion of "forget" (F) words. After removing the immediate recall test, Experiment 2 found that intentionally forgetting part of the studied list reduced false memory, whereas forgetting the whole studied list did not. The results are discussed in terms of the list-level-vs.-item-level inhibition in semantic activation and the role of monitoring in reducing false memory.     

Time of day and processing strategy in free recall

Consistent effects of time of day have been observed in digit span/sequence performance, and in the immediate memory for information presented in prose. However, studies using syntactically unstructured word lists have yielded inconsistent results. Three experiments were conducted that examined the free recall of 15 word lists. In all three, immediate recall from the pre-recency positions was found to be superior in the morning to the afternoon. This superiority disappeared after a 20-min delay (Experiment 1) and under articulatory suppression (Experiment III), but was unaffected by a manipulation that equated recall order (Experiment II). Immediate recall from the recency positions showed a W-shaped trend over the day (Experiment I) that might account for the inconsistencies previously reported. It is suggested that the changes in recall from the pre-recency positions may reflect a decrease in maintenance, and increase in elaboration, over the day. Such a change in processing strategy could itself reflect an increase in attentional selectivity associated with the changes in basal arousal level commonly held to occur over the day.     

Aging and memory for words and action events: effects of item repetition and list length

We were concerned with the effects of item repetition, list length, and class of item on free recall in elderly as compared with young adults. In Experiment 1, samples of young and elderly adults recalled a list of 27 words and a list of 27 action events (minitasks performed by the subjects). Some items were presented once and some twice. Although the younger subjects showed better recall on both types of lists, the older sample benefited from item repetition as much as did the younger sample. This finding was replicated in Experiment 2. A second finding in Experiment 2 was a significant aging effect in the recall of long but not of short lists of both words and action events. The absence of an Age X Repetition Effect interaction was ascribed to the strength nature of the repetition manipulation. The age effects in the recall of the long lists were attributed to possible deficits in retrieval proficiency.     

Is there a modality effect? Evidence for visual recency and suffix effects

In Experiment 1, four groups of 16 subjects performed ordered recall of six-syllable lists in both suffix and nonsuffix conditions. Sequential presentation of the lists varied for each group. In the auditory presentation, the syllables were delivered from one location only and were read aloud by the subjects. For the visual, spatially nondistributed presentation, the syllables appeared in one location only and were read silently. For visual, spatially distributed presentations, the syllables were spread out either vertically or horizontally and were read silently. Very robust recency and suffix effects were found in the auditory presentation, as well as in visual, spatially distributed presentations. In Experiment 2, 16 subjects performed ordered recall of visually presented lists with the items spread out vertically and conflicting spatial and temporal orders. A reliable recency effect was found for the final block of trials. In Experiment 3, 16 subjects performed ordered recall in the same conditions as in Experiment 2, except that they were instructed to recall the temporal order in which the spatial positions would be filled in. A bow-shaped curve and a strong recency effect were obtained.     

Alcohol and unpleasant stimulation: subjective shock calibration and pain and discomfort perception

In an experiment 8 men participated in an alcohol and a sober condition in a rotated order. In both conditions subjects first calibrated a shock scale to a subjective criterion and then rated their subjective pain and total discomfort. Subjects calibrated the shock scale higher when intoxicated and rated the calibrated level equally painful in the sober and intoxicated conditions, but when intoxicated subjects actually rated the higher shock level as less uncomfortable. The shock scale was calibrated higher under intoxication not because subjects wanted to impress the experimenter but because less pain and discomfort was actually experienced.     

Effects of phonological similarity and concurrent irrelevant articulation on short-term-memory recall of repeated and novel word lists

The extent to which phonological similarity of list words impairs short-term-memory recall was investigated in two experiments. Experiment 1 showed that the phonological-similarity effect occurred both when list words were repeatedly sampled from a small set and when they were new on every trial, both when word-order information was required and when it was not. Furthermore, the adverse effect of phonological similarity on recall was apparent on the initial lists recalled, did not change over trials, and cannot be attributed to increasing levels of proactive inhibition across lists. In Experiment 2, subjects were required to count repeatedly to six during list presentation. Concurrent irrelevant articulation lowered recall and abolished the phonological similarity effect for both repeated and novel word lists.     

The stimulus suffix effect as a memory coding phenomenon

Two short-term memory experiments examined the nature of the stimulus suffix effect on auditory linguistic and nonlinguistic stimulus lists. In Experiment 1, where subjects recalled eight-item digit lists, it was found that a silently articulated digit suffix had the same effect on recall for the last list item as a spoken digit suffix. In Experiment 2, subjects recalled lists of sounds made by inanimate objects either by listing the names of the objects or by ordering a set of drawings of the objects. Auditory suffixes, either another object sound or the spoken name of an object, produced a suffix effect under both recall conditions, but a visually presented picture also produced a suffix effect when subjects recalled using pictures. The results were most adequately explained by a levels-of-processing memory coding hypothesis.     

Recall accuracy and illusory memories: when more is less

In two experiments it was revealed that manipulations that increased recall of studied list items also increased false recall of theme-related, critical nonpresented words. In Experiment 1 subjects listened to a series of short word lists, each containing items associatively related to a theme, while engaging in either semantic or nonsemantic processing. On an immediate free recall test semantic processors demonstrated greater correct recall as well as more illusory memories of critical nonpresented items than nonsemantic processors. In Experiment 2, the short study lists were combined to form longer lists that were presented either blocked by theme or in a random presentation order. Retention interval was also varied as participants were tested either immediately, one week after, or three weeks after the study phase. Presenting the target items in a blocked, as opposed to random, format increased recall accuracy, but this was at the expense of a higher intrusion rate for theme-consistent items. Interestingly, the level of false memories was not affected by retention interval even though typical decrements in the recall of study items were observed over time. The results of these experiments highlight the persistence of the false memory effect, as well as pointing to several factors, primarily semantic processing, that may lead to the creation of false memories. Interpretations are offered within the theoretical frameworks of source monitoring and fuzzy trace theory.