Some tests of the decay theory of immediate memory

The hypothesis of decay of the memory trace as a cause of forgetting has been unpopular. The reasons for this unpopularity are criticized and a theory of the memory span, based on this hypothesis, is put forward. Three experiments which test the hypothesis are described. In each, two kinds of stimuli are presented to the subject, viz., “required” stimuli, which he attempts to remember, and “additional” stimuli, to which he merely makes responses. The first experiment will show that even when the number of required stimuli is well below the memory span, forgetting occurs if the presentation of additional stimuli delays recall for several seconds. The second shows that the effect of the additional stimuli depends only slightly on their similarity to the required stimuli: it also shows that their effect is negligible when they precede, instead of follow, the required stimuli. The third shows that the effect of additional stimuli interpolated before recall remains considerable even when there is an interval of several seconds between presentation of required and additional stimuli.     

Imagery and associative memory in children

Second and sixth graders, ages 7–8 and 11–12, respectively, were presented with lists of pairs of nouns. They were asked to represent each pair in memory as a single interactive image, as two separate images, or by a control procedure. After presentation of the pairs, the children were tested either by cued or noncued recall. The difference between the interaction condition and the other conditions appeared in recall measures which reflect pairwise organization in memory (cued recall, pair recall, conditional recall probabilities, and χ²) to a much greater extent than in measures of individual item recall. The results were interpreted as supporting an imagery-organization hypothesis.     

Visual and phonological components of working memory in children

Previous studies have shown that young children's immediate memory for a short series of drawings of objects is mediated by a visual component of working memory, whereas older children rely chiefly upon a phonological component. Three experiments investigated the hypothesis that older children rely also, but to a lesser extent, on visual working memory. Experiment 1 confirmed previous evidence that 11-year-olds' memory is disrupted by phonemic similarity of object names, but is unaffected by visual similarity of the objects themselves. However, when articulatory suppression was used to prevent phonological coding, levels of recall were sensitive to visual rather than phonemic similarity. Experiment 2 compared the effects of interpolating an auditory-verbal or a visual postlist task on memory for drawings viewed either with or without suppression. The visual task had a clear disruptive effect only in the suppression condition, where it interfered selectively with recall of the most recent item. Experiment 3 compared the effects of interpolating an auditory-verbal or a mixed-modality (visual-auditory) postlist task when subjects were not required to suppress. There was greater interference from the mixed-modality task, and this effect was confined to the last item presented. These experiments are taken as confirming the presence of a small but reliable contribution from visual memory in 11-year-old children's recall. As in younger children, visual working memory in 11-year-olds is sensitive to visual similarity and is responsible for a final-item visual recency effect. The results also show that older children's use of visual working memory is usually masked by the more pervasive phonological component of recall. Some implications for the structure of working memory and its development are discussed.     

The role of expectancy in comparative judgments

Researchers interested in the processing of relational information have sought a satisfactory explanation for the congruity effect in linear orders. It is relatively easy to select either the greater of two objects that are high on a dimension or the lesser of two objects that are low on a dimension, but it is relatively difficult to determine the greater of two objects that are low in magnitude or the lesser of two objects that are high in magnitude. One explanation of the congruity effect is the expectancy hypothesis that claims that the choice of the comparative primes objects of particular magnitudes. We present two experiments that demonstrate that a congruity effect of equivalent magnitude is obtained when the comparative is presented after the stimulus pair. Moreover, this equivalence cannot be attributed to the salience of the dimensions we employed, because this equivalence held for stimuli that were classified as salient and for those classified as nonsalient. These findings are interpreted in the context of some current explanations of the congruity effect.     

The Supposed Effect of Interactive Imagery in Paired Associate Learning

Previous experiments designed to investigate the effects of interactive imagery in paired associate learning have included the confounded variable of intralist similarity: Images of objects interacting have corresponded to pairs with different connectives, and images of independent objects have corresponded to pairs with the same connective (the conjunction 'and'). For the 'different' group of our first experiment, the members of the different pairs were linked by different connectives, most of which denoted an action. For the 'same' group, the members were linked by the same connective, usually one denoting an action. For the 'and' group, the members were linked by the connective 'and'. Cued recall by the 'different' group was superior to that of the other two groups. Recall by the 'same' and 'and' groups did not differ. Within the 'different' group, recall of 'and' pairs did not differ from the recall of 'action' pairs with which they had been mixed. In a second experiment, subjects were required to match the members of a pair. Analogous results were obtained. Overall, the findings imply that recall effects that have previously been interpreted as being a result of interactive imagery may be the result merely of variations in intralist similarity.     

The effects of an acute psychosocial stressor on episodic memory

Although stressors are believed to impair memory, experimental studies with humans have provided inconsistent support for this conclusion. The current study was designed to examine the effect of an acute psychosocial stressor, and subsequent reactivity, on episodic memory. One hundred participants completed a list-recall task before and after random assignment into a stressor or nonstressor condition. Participants assigned to the stressor condition exhibited both impaired delayed and immediate recall, and also exhibited increasesin the commission of intrusions and perseverations. The experience of off-task thoughts and intentional suppression of such thoughts, were associated with greater impairment of immediate recall. Changes in state anxiety, negative mood, and heart rate were unrelated to changes in memory. These data indicate that exposure to a stressor impaired the recall of previously learned information, and compromised the recall of newly acquired information. Furthermore, cognitive interference is an important factor regarding stress-related impairments of episodic memory.     

Semantic specificity in cued recall

In three cued recall experiments, extralist retrieval cues that were congruous in meaning to an encoded target pair of words produced better recall of the targets than wh6n the cuetarget relation was incongruous. However, this result, which differs from that of other experiments, depended in some cases on scoring recall of a target pair when either member of the pair was recalled. It is argued that (1) pairs of words are typically stored as higher order units, (2) the best test procedure is to request recall of both members of the pair when an extralist cue is presented, and (3) semantic features provide an important dimension in the mnemonic representation of word events.     

A developmental study of relations between free recall, cued recall, and recall of incidental material

Six-, 9-, 17–19-, 45–55-, and 65-year-old subjects were shown 16 slides depicting one colored object and two uncolored context objects in a common setting, the task being to learn the names of the colored objects. Free and cued recall of both colored and context items were tested, the context objects being used as retrieval cues for the colored ones, and vice versa. The relative superiority of cued recall to free recall decreased regularly with increasing age. In the oldest subjects the level of free recall of TBR-objects was still fairly high, the level of recall of context objects being very low. The results support the hypothesis that adults encode nominally irrelevant context materials to a decreasing extent with increasing age, and that memory traces of young people in this sense are "richer", i.e., contain a greater number/variety of potential retrieval cues, than those of the elderly.     

Impressions of force in visual perception of collision events: A test of the causal asymmetry hypothesis

When two objects interact they exert equal and opposite forces on each other. According to the causal asymmetry hypothesis, however, when one object has been identified as causal and the other as that in which the effect occurs, the causal object is perceived as exerting greater force on the effect object than the latter is perceived as exerting on the former. An example of this is a stimulus in which one object moves toward another stationary one, and when contact occurs the former stops and the latter moves away. In this situation the initially moving object is identified as causal, so the causal asymmetry hypothesis predicts that more force will be judged to be exerted by the moving object on the stationary one than by the stationary one on the moving one. Participants’ judgments consistently supported this hypothesis for a variety of stimuli in which kinematic parameters were varied, even when the initially moving object reversed direction after contact.     

协作抑制的作用机制：来自编码阶段的证据

协作抑制是指当人们在一个记忆小组中一起提取信息的时候,小组提取的信息总量比等量个体提取的信息总量要少。本研究采用经典的协作抑制研究范式和两次提取任务,考察编码方式和学习次数对协作提取任务的影响,进一步将考察协作抑制的产生机制作为总研究目的。结果表明,编码方式相同条件下出现协作抑制,而编码方式不同条件下协作抑制消失,显示协作抑制的出现与否依赖于认知条件的改变;无论是学习一次还是学习两次,在第一次小组提取中出现协作抑制,而在第二次个人提取中协作抑制消失,在使用困难学习材料时也得到同样的研究结果。研究结果支持协作抑制的提取策略破坏假说。     

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.     

Facilitation of free recall by categorical blocking depends on stimulus type

Items that are blocked by category are typically more memorable than unblocked items. We examined the blocking effect with different types of stimuli. In Experiment 1, subjects memorized either actual objects or the printed names of those objects. Free recall was enhanced significantly by blocking only in the printed name condition. In Experiment 2, it was demonstrated that these relationships occurred whether or not verbal labels are supplied for the stimulus items. The difference in the impact of blocking on free recall was hypothesized to reflect differences in the visual detail that characterized the stimulus items in the object and printed name conditions. To test this hypothesis, Experiment 3 was conducted, using four sets of stimulus items graded in visual detail. These were a set of objects, photographs of the objects, line drawings of the objects, and printed names of the objects. The visual detail hypothesis was supported.     

Peer discussion affects children's memory reports

This study explored the memory conformity effect in children. Younger (6–7 years; n = 60) and older (11–12 years; n = 62) children watched a video individually (individual witness condition) or in dyads (co‐witness condition). The dyads believed that they were viewing the same video as the other member of the pair while in fact the saw different versions. Next, children in the individual witness condition answered questions, whereas children in the co‐witness condition discussed the event on the video with each other. Finally, all children completed an individual free and cued recall task. In the co‐witness condition, more than 60% of the children recalled at least one detail from the alternative video, whereas over 23% of the children in the individual witness condition reported such a detail. Moreover, in free recall—but not in cued recall—the memory conformity effect was stronger for older than for younger children. Copyright © 2007 John Wiley & Sons, Ltd.     

Cross-task repetition amnesia: Impaired recall of RSVP targets held in memory for a secondary task

People often fail to select and encode the second of two targets presented within less than 500ms in rapid serial visual presentation (RSVP), an effect known as the attentional blink. We investigated how report of the two targets is affected when one of them is maintained in working memory for a secondary, memory-search task. The results showed that report of either target was impaired when it was a member of the memory set relative to when it was not. This effect was independent of both the temporal interval separating the RSVP target from the presentation of the memory set and the interval separating the targets. We propose that the deficit in recall occurs because the association between a target and the memory-search task interferes with the formation of a new association between that target and the following RSVP task, with the result that observers may be biased to ascribe the target only to the memory set.     

Masking and the identification of characters presented simultaneously and sequentially to the parafovea

Summary The effects of masking and simultaneous vs sequential exposure on identification accuracy of parafoveally presented pairs of stimuli were examined in four experiments. When masking figures were continuously present in positions not occupied by stimulus characters, accuracy of identification was significantly poorer on the relatively central member of a pair when members were simultaneously exposed and when the central member was exposed second. When masking figures were not used, performance was significantly poorer on the central member only when pair members were exposed simultaneously. Requiring the identification of both members of the pair produced a different ordering of overall accuracy among the simultaneous and sequential conditions from when only one member was identified. It was concluded that asymmetric lateral inhibition of feature extraction operated only when target and nontarget were simultaneously present. An additional source of asymmetric disruption occurs when masking figures flanking the target change before or with the appearance of the target.     

The spacing effect in intentional and incidental free recall by children and adults: Limits on the automaticity hypothesis

Preschoolers, elementary school children, and college students exhibited a spacing effect in the free recall of pictures when learning was intentional. When learning was incidental and a shallow processing task requiring little semantic processing was used during list presentation, young adults still exhibited a spacing effect, but children consistently failed to do so. Children, however, did manifest a spacing effect in incidental learning when an elaborate semantic processing task was used. These results limit the hypothesis that the spacing effect in free recall occurs automatically and constrain theoretical accounts of why the spacing between repetitions affects recall performance.     

The effects of repeated idea elaboration on unconscious plagiarism

Unconscious plagiarism occurs in a recall task when someone presents someone else’s idea as his or her own. Recent research has shown that the likelihood of such an error is inflated if the idea is improved during the retention interval, but not if it is imagined. Here, we explore the effects of repeating the elaboration phase during the retention interval. Participants in a group first generated alternate uses to common objects before elaborating the ideas either by imagining them or by improving them. This elaboration phase occurred once, twice, or not at all. Later, they attempted to recall their original ideas and generate new ideas. Repeated imagery did not inflate unconscious plagiarism on either task. In contrast, repeating the improvement phase increased plagiarism to dramatically high levels in the recall task. The latter effect might be particularly pertinent to real-world cases of plagiarism in which the ideas under dispute have been the subject of creative development over many occasions.     

Retrieval-induced forgetting and unwanted thought intrusions

The act of retrieving an existing memory has been found to inhibit the recall of related memories, a phenomenon known as retrieval-induced forgetting (RIF). The purpose of the present study was to investigate the hypothesis that individuals with a strong RIF effect might be better at suppressing unwanted intrusive thoughts. In Experiment 1 the relationship between RIF and the prevalence of intrusive thoughts was investigated using a sample of 58 normal British participants, who completed three different questionnaires to measure their susceptibility to intrusive thoughts, obsessional thoughts, and impulsive thoughts. Their susceptibility to RIF was also measured, using the standard procedure introduced by Anderson, Bjork, and Bjork (1994). The results showed a significant RIF effect, and, although no significant correlations were found between RIF strength and any of the three measures of intrusive thoughts, there was some evidence to suggest a possible relationship between RIF and intrusive thoughts. In an effort to clarify these inconclusive findings, Experiment 2 investigated the relationship between RIF and intrusive thoughts in a different and more varied population sample, consisting of 90 normal members of the Greek population. Experiment 2 confirmed the RIF effect, but no significant association was found between RIF and intrusive thoughts. These findings therefore offer no support for the hypothesis that RIF assists the suppression of intrusive thoughts in normal individuals.     

Thinking about memories for everyday and shocking events: Do people use ease-of-retrieval cues in memory judgments?

Extant research shows that people use retrieval ease, a feeling-based cue, to judge how well they remember life periods. Extending this approach, we investigated the role of retrieval ease in memory judgments for single events. In Experiment 1, participants who were asked to recall many memories of an everyday event (New Year's Eve) rated retrieval as more difficult and judged their memory as worse than did participants asked to recall only a few memories. In Experiment 2, this ease-of-retrieval effect was found to interact with the shocking character of the remembered event: There was no effect when the event was highly shocking (i.e., learning about the attacks of September 11, 2001), whereas an effect was found when the event was experienced as less shocking (due either to increased distance to "9/11" or to the nonshocking nature of the event itself). Memory vividness accounted for additional variance in memory judgments, indicating an independent contribution of content-based cues in judgments of event memories.