Implicit memory and depression: An analysis of perceptual and conceptual processes

A small number of studies have reported impaired explicit memory and intact implicit memory performance in participants classified as depressed. In the present study we examined this finding taking account of the distinction between datadriven and conceptually driven processing. The performance of participants diagnosed with depression was examined on implicit and explicit memory tasks which were designed to tap either predominantly perceptual or conceptual processes. Depressed participants demonstrated performance deficits on both the implicit and explicit conceptual tasks (category association and free recall, respectively) but showed intact performance in the implicit perceptual task (word-fragment completion). These results suggest that people with severe depression show deficits in conceptual processing and that this deficit occurs under both explicit and implicit task instructions.     

An investigation of false memory in perceptual implicit tasks

Reports of critical lure priming in perceptual implicit tasks [e.g., McKone, E., & Murphy, B. (2000). Implicit false memory: Effects of modality and multiple study presentations on long-lived semantic priming. Journal of Memory and Language, 43, 89-109] using the Deese-Roediger-McDermott [Roediger, H. L., III, & McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, and Cognition, 21, 803-814] procedure have suggested availability of the lexical form of lure items at study. Three experiments were conducted to further explore "false" implicit priming in perceptual tests. In Experiments 1 and 3, implicit and explicit stem completion tests were given in the DRM procedure with semantic lists; in Experiment 2, a graphemic response test was used in a similar design. For all experiments, explicit instructions resulted in reliable false memory, while implicit instructions resulted in priming for list items and no priming for lure items. Priming for lure items was evident for "test-aware" subjects only in Experiment 1 and in a combined analysis for all three experiments. These results establish boundary conditions for priming for critical lures and indicate that access to the lexical form of critical lures may not occur under incidental learning conditions when strong controls against explicit retrieval are implemented.     

Levels-of-processing effects on Chinese character completion: The importance of lexical processing and test cue

The levels of processing (LoP) effect was studied in Chinese character completion tasks. The same stem cue, either graphemically or semantically related to the target character, was used to generate either a perceptual or a conceptual test. Participants received either direct or indirect instructions, so that the same stem cue also produced either an explicit or an implicit test of memory. This allowed us to examine simultaneously the roles of perceptual versus conceptual test and retrieval intentionality in the LoP effect. No LoP effects were found when the memory test was implicit. LoP effects were also not found for stems and characters related graphemically (perceptually), but were found for stems and characters related semantically (conceptually) when the memory test was explicit. The results are discussed in terms of the importance of lexical processing for character completion tests and the importance of reinstatement of the study process during retrieval for explicit memory tests.     

Transfer across modality in perceptual implicit memory

We examined whether words studied in one modality (visual or auditory) would prime performance in the opposite modality in five different perceptual implicit memory tests: auditory perceptual identification, auditory stem completion, visual perceptual identification, visual stem completion, and visual fragment completion. Significant transfer across modality was observed in all five tasks. However, a large proportion of the subjects reported using explicit retrieval strategies during the implicit tests. Those subjects who claimed not to have used explicit retrieval processes during the test phase demonstrated transfer across modalities in the stem completion tests and the perceptual identification tests, but not in the fragment completion test. The results indicate that implicit visual word-fragment completion is unique, in the sense that it relies exclusively on perceptual memory processes, whereas the other tasks rely, in part, on nonperceptual memory processes.     

Effects of color on perceptual and conceptual tests of implicit memory

Two experiments are reported that explore why recent investigations of implicit memory failed to find any effects of color information on test performance. In the first experiment, participants studied colored pictures as well as words printed in colored ink without any memory instructions. During the test phase, a verbal and a pictorial version of a color-choice task (a conceptual priming test) were compared to two perceptual tests (word-stem completion and picture-fragment identification). Similar and significant amounts of priming to color occurred in both color-choice tasks. The perceptual tests were found to be sensitive to changes in the stimulus-presentation mode from study to test, but stimuli remaining the same color and those changed to black-and-white did not differ in the priming scores. In the second experiment, a mild division of attention was introduced in the study phase. Once again, priming to color was observed only in the verbal version of a color-choice test and not in the word-stem completion test. Dividing attention did not decrease performance on both implicit tests, whereas an explicit test of color recall for studied pictures suffered from dividing attention at encoding. It is concluded that a perceptual attribute such as color may be represented and coded by conceptual processing. Furthermore, automatic (or not attention-demanding) encoding processes may suffice for later conceptual tests of implicit memory. Previous failures to find any effects of color information on implicit performance are attributed to the use of perceptual priming tests. Received: 30 June 1997 / Accepted: 20 April 1998     

概念内隐记忆中的注意促进效应

Swallow和Jiang (2010)最早发现, 编码时的目标探测会促进同时呈现的背景信息在随后记忆测验中的表现, 并将这一现象称为注意促进效应(Attentional Boost Effect, ABE)。随后研究发现这一现象并不会出现在概念内隐测验中, 由此提出目标探测主要促进的是背景信息的知觉加工, 而非语义加工。本研究通过3个实验, 操纵了对背景信息的编码加工类型(知觉加工或概念加工)。结果发现, 当与目标探测同时进行的是对背景信息的概念加工任务, 则ABE会出现在随后的概念内隐测验中。反之, 当对背景信息进行的是知觉加工任务时, 则ABE会出现在随后的知觉内隐测验而不是概念内隐测验中。这些结果表明, 目标探测既可能促进背景信息的知觉加工, 也可能促进背景信息的语义加工, 但只有在目标探测下背景信息的编码加工与随后内隐测验中所依赖的提取加工具有一致性, 才会产生ABE。     

提取干扰对知觉和概念启动的影响

通过学习—测验范式，分别以词汇判断、语义分类任务为测验，探讨提取干扰对不同识别式记忆的影响差异。结果发现，实验1验证了识别式知觉内隐记忆的提取干扰效应，实验2发现识别式概念内隐记忆在提取干扰下也明显降低；两个实验启动量联合分析发现，相比无干扰条件，概念启动比知觉启动受到提取干扰的破坏更大。上述结果说明识别式内隐记忆的提取干扰具有普遍性，提取干扰产生了不同识别式内隐记忆之间的分离，识别式概念内隐记忆更容易受到提取干扰的影响。     

知觉和概念加工范式对内隐与外显记忆发展的影响

控制知觉材料的熟悉性和概念范例的典型性,以考察它们对内隐与外显记忆发展的影响。结果表明：（1）知觉内隐记忆的启动效应不存在年龄和熟悉性效应,而知觉外显记忆成绩则具有明显的年龄和熟悉性效应;（2）在概念内隐记忆任务上,典型范例的启动效应不存在年龄差异,非典型范例的启动效应则存在随年龄而增长的启动效应：无论是典型范例还是非典型范例的外显记忆成绩均随年龄增长而提高。     

Perceptual and lexical components of auditory repetition priming in young and older adults

In the present study, we examined whether age modulates the processing of lexical and perceptual information in auditory implicit and explicit memory tests. Young and older adults performed a surface encoding task on spoken and printed words and then either identified degraded words or made explicit recognition judgments. The implicit test of perceptual identification yielded no evidence of age-related declines in the processing of either lexical information or coarse perceptual details (modality of presentation). The same test, however, produced marked age-related declines in the processing of fine-grained perceptual details (voice) when subjects were not familiarized with the talkers' voices prior to the encoding task. Marked age differences were also observed in recognition memory. These findings suggest that although aging preserves the encoding and incidental retrieval of lexical and coarse perceptual information, it affects the encoding of fine-grained perceptual information and deliberate retrieval processes.     

Implicit memory for textual materials

As a word moves from isolation in a list to being contextually bound in meaningful discourse, its probability of priming in tests of implicit memory decreases. The present experiments explore whether considerable priming effects can be revealed with conceptual tests of implicit memory as compared to perceptual tests. In the study phase, meaningful actions were described within a coherent text. In Experiment 1 subjects elaborated half of the actions by visual imagery. In Experiment 2, subjects elaborated the actions by enacting them symbolically. In both experiments, subjects in a control condition were simply required to read the same activities. In Experiment 2, a further group of subjects had to detect orthographic errors. The results demonstrated reliable effects of implicit memory in terms of associations with verbs repeated from the studied text. This form of repetition priming for textual materials in a conceptual test of implicit memory was enhanced by both types of elaboration. A word-stem completion task for the same targets revealed a less pronounced and inconsistent priming effect, uninfluenced by both types of elaboration. But the latter form of perceptual priming was found to be more pronounced within the error-detection condition. Measures of explicit memory showed similar effects of elaborative encoding conditions but there were some dissimilarities to measures of implicit memory, too. In general and in accordance with a transfer-appropriate processing view, conceptual tests rather than perceptual tests may be more suitable for detecting effects of implicit memory within the domain of text processing.     

How "implicit" are implicit color effects in memory?

Processing colored pictures of objects results in a preference to choose the former color for a specific object in a subsequent color choice test (Wippich & Mecklenbr?uker, 1998). We tested whether this implicit memory effect is independent of performances in episodic color recollection (recognition). In the study phase of Experiment 1, the color of line drawings was either named or its appropriateness was judged. We found only weak implicit memory effects for categorical color information. In Experiment 2, silhouettes were colored by subjects during the study phase. Performances in both the implicit and the explicit test were good. Selections of "old" colors in the implicit test, though, were almost completely confined to items for which the color was also remembered explicitly. In Experiment 3, we applied the opposition technique in order to check whether we could find any implicit effects regarding items for which no explicit color recollection was possible. This was not the case. We therefore draw the conclusion that implicit color preference effects are not independent of explicit recollection, and that they are probably based on the same episodic memory traces that are used in explicit tests.     

Effect of divided attention on explicit and implicit aspects of recall

If subjects have to form word images before spelling a word from the image, results of a repetition of the spelling test reveal a reliable priming effect: Old words can be spelled faster than comparable control words, reflecting a form of implicit memory. We investigated whether this kind of repetition priming remains stable under conditions of divided attention in the study phase. The subjects had to spell meaningful words, meaningless non-words, and non-words that were meaningful with a backward spelling direction (troper, for example). In the testing stage, recognition judgments as a form of explicit memory were required, too. Divided attention in the study phase had a negative effect on explicit memory, as revealed by performance on the recognition task, but had little effect on implicit memory, as revealed by performance on the repetition of the spelling test. A further dissociation between implicit and explicit memory showed up as meaningful words were recognized much better than non-words, whereas implicit memory was uninfluenced by the meaningfulness variable. The disadvantage of backward spellings was not reduced with non-words (like troper) spelled backwards. Finally, we analyzed the relations between spelling times and recognition judgments and found a pattern of dependency for non-words only. Generally, the results are discussed within processing-oriented approaches to implicit memory with a special emphasis on controversial findings concerning the role of attention in different expressions of memory.     

An examination of the effects of adult age on explicit and implicit learning of figural sequences

Memory for previously learned figural sequences and item-to-item covariations within figural sequences was examined under explicit and implicit instructional conditions in three age groups: young adults (17-23 years); middle-aged adults (35-45 years); and older adults (55-65 years). In Phase 1 of the experiment, the acquisition phase, half the subjects in each age group learned sequences of three to eight items in which the item-to-item changes conformed to an artificial grammar, and the other half of the subjects in each age group learned strings in which the item-to-item changes were nongrammatical. In Phase 2, the implicit/explicit test phase, subjects made forced-choice judgments about parts of the strings that they learned in Phase 1, under either explicit or implicit instructions. Analyses of Phase 2 data revealed that subjects in both instructional conditions used item-to-item covariations in making decisions about grammatical strings. However, use of previously learned covariations as well as the number of correct judgments about previously learned strings was greater in the explicit condition than in the implicit condition. An age-related deficit was found for explicit recognition of grammar-following sequences.     

Midazolam amnesia and conceptual processing in implicit memory

Prominent theories of implicit memory (D. Schacter, B. Church, & J. Treadwell, 1994) emphasize the dominant role of perceptual processing in mediating priming on perceptual implicit memory tests. Examinations of the effects of conceptual processing on perceptual implicit memory tests have produced ambiguous results. Although a number of investigations (e.g., J. Toth & R. Hunt, 1990) have demonstrated that variations in conceptual processing affect priming on perceptual implicit memory tests, these effects may arise because of the contaminating effects of explicit memory. The current experiment examined this controversy using midazolam, a benzodiazepine that produces a dense, albeit temporary, anterograde amnesia when injected prior to study. The experiment examined whether the effects of generation found on the implicit memory test of perceptual identification were affected by a midazolam injection prior to study. Results demonstrated that midazolam substantially diminished generation effects in free and cued recall, as well as overall performance on these tests, but had no detectable effect on the generation effect in perceptual identification.     

Exposure effects on music preference and recognition

In three experiments, the effects of exposure to melodies on their subsequent liking and recognition were explored. In each experiment, the subjects first listened to a set of familiar and unfamiliar melodies in a study phase. In the subsequent test phase, the melodies were repeated, along with a set of distractors matched in familiarity. Half the subjects were required to rate their liking of each melody, and half had to identify the melodies they had heard earlier in the study phase. Repetition of the studied melodies was found to increase liking of the unfamiliar melodies in the affect task and to be best for detection of familiar melodies in the recognition task (Experiments 1, 2, and 3). These memory effects were found to fade at different time delays between study and test in the affect and recognition tasks, with the latter leading to the most persistent effects (Experiment 2). Both study-to-test changes in melody timbre and manipulation of study tasks had a marked impact on recognition and little influence on liking judgments (Experiment 3). Thus, all manipulated variables were found to dissociate the memory effects in the two tasks. The results are consistent with the view that memory effects in the affect and recognition tasks pertain to the implicit and explicit forms of memory, respectively. Part of the results are, however, at variance with the literature on implicit and explicit memory in the auditory domain. Attribution of these differences to the use of musical material is discussed.     

Does conceptual implicit memory develop? The role of processing demands

The author investigated the importance of processing considerations within implicit memory in a developmental design. Second-graders (n = 87) and college students (n = 81) completed perceptual (word stem completion) and conceptual (category generation) implicit memory tests after studying target items either nonsemantically (read) or semantically (generated). In support of previous research, the author found no age differences in priming in the nonsemantic study/perceptual test condition. Age differences in priming were found in the semantic study/conceptual test condition, however, where college students had significantly higher priming scores than did children. These developmental dissociations support the theory that the processing requirements of conceptual implicit memory are similar to those in explicit memory. The author also discusses the contribution of the Transfer Appropriate Processing (TAP; H. L. Roediger, D. A. Gallo, & L. Geraci, 2002) framework to understanding these findings.     

Correlational analyses of explicit and implicit memory performance

Sixty-four subjects were administered two tests of explicit memory (selective recall and recognition) and four tests of implicit memory (identification in a perceptual clarification procedure, word-fragment completion, tachistoscopic identification, and anagram solution). Each test drew on a different subset of a long list of previously displayed words. Although the four implicit memory tests showed sizable priming effects, correlational and factor analyses showed striking dissociations. On the one hand, performance on the perceptual clarification procedure and word-completion tests were related to one another, as well as to recall and recognition. On the other hand, performance on tachistoscopic identification and anagram solution were related to one another, but not to the measures for the other tasks. A framework is proposed to reconcile these new results with current knowledge on the explicit/implicit memory distinction, based in particular on studies of amnesic subjects. It is argued that a small number of tasks, especially tachistoscopic identification, may serve as relatively uncontaminated and ubiquitous indicators of implicit memory. However, explicit remembering could affect performance in so-called implicit memory tasks that allow for a strategy of controlled selection of candidate responses from accumulating cues, in experimental conditions that make the explicit remembering of relevant events possible.     

Dissociation of implicit and explicit memory tests: Effect of age and divided attention on category exemplar generation and cued recall

In this article, we report an experiment that provides further evidence concerning the differences between explicit and implicit measures of memory. The effects of age and divided attention on the implicit conceptual test of category exemplar generation (CEG) were compared with their effects on the explicit test of cued recall, where the category names served as cues in both tasks. Four age groups (20–35, 40–55, 60–75, and 76–90) were compared. Half of the subjects were also required to carry out a secondary letter-detection task during the learning phase. Cued recall performance was significantly impaired by increased age and imposition of the secondary task. In contrast, the CEG task was unaffected by these two factors. These results suggest that implicit conceptual tasks and explicit memory tasks are mediated by different processes. This conclusion opposes those of previous studies that showed that experimental manipulations (level of processing, generation, organization) influenced these two kinds of memory tests in a similar way.     

Effects of aging on implicit sequence learning: Accounting for sequence structure and explicit knowledge

The present research was intended to examine the sequence learning ability of elderly people — with a focus on comparing sequences with different structural characteristics and on properly assessing explicit knowledge. Experiment 1 showed that learning-related improvements in serial reaction time task performance were greater for young than elderly subjects, and elderly subjects were especially poor at learning a sequence with complex structural characteristics. Measures of recognition memory showed that neither young nor elderly subjects showed above-chance explicit knowledge of the sequences. Experiment 2 was designed to test the validity and sensitivity of the explicit recognition measures by comparing young subjects in groups given all random trials, given sequence trials with implicit instructions, or given sequence trials with explicit instructions. Experiment 2 confirmed the sensitivity of the recognition measures to explicit knowledge, so it is concluded that group effects in Exp. 1 reflect age-related differences in implicit learning.     

Implicit and explicit memory without awareness

Summary Three experiments are reported which investigate the conscious status of subjects during an implicit-memory test. In all experiments the subjects either named each visually presented target item or generated each item from an anagram in a first phase of incidental learning. In a second phase, they were either given a visual word-stem completion task as an implicit-memory test or given a recognition task (Experiment 1), or a cued-recall task (Experiments 2 and 3) as explicit-memory tests. Finally, in a third phase the subjects were required to make decisions about the input status (i. e., they had to decide whether the item was present in the first phase) as well as about the output status of information (i. e., they had to decide whether the item had been completed, recognized or recalled in the second phase). A generation effect (i. e., generated items were remembered better than named items) was evident in the recognition and recall data, but only for items whose recognition or recall was accompanied by conscious recollection of their previous occurrence in the study list. Judgments about the input status were more precise, given that items had been consciously recognized or recalled rather than completed. The same pattern of findings was observed for judgments about the output status. The results are interpreted as evidence that subjects in implicit-memory tests are less aware of the fact that some of their productions are relevant to prior experiences. In addition, they are less aware of the fact that they are retrieving information from their memories. However, the same state of nonawareness may be present in explicit-memory tests, as was revealed by the performance of subjects on those items whose recognition or recall was not accompanied by conscious recollection.