A Developmental Trajectory in Implicit Memory is Revealed by Picture Fragment Completion

Dissociations between performance on implicit and explicit tasks have often been taken as evidence that different neural structures subserve the two types of memory. One such dissociation involves developmental differences that emerge in explicit tasks, but which appear to be absent in implicit tasks. Such findings are consistent with the idea that implicit memory is subserved by a more primitive system that evolves earlier at both phylogenetic and ontogenetic levels. The present paper reviews previous studies that claimed to find evidence that implicit memory is fully developed in very young children. Issues of measurement error, ceiling effects, and insufficient power brought up questions about those studies with respect to the developmental issue. The present study compares performance on implicit (picture fragment completion) and explicit (free recall and recognition) memory tasks with groups ranging in age from 5–28 years. We find a reliable developmental trend in both implicit and explicit performance in which the former cannot be attributed to the operation ofexplicit memory processes. Thus, we conclude that implicit memory, like explicit memory, develops with age.     

A developmental trajectory in implicit memory is revealed by picture fragment completion

Dissociations between performance on implicit and explicit tasks have often been taken as evidence that different neural structures subserve the two types of memory. One such dissociation involves developmental differences that emerge in explicit tasks, but which appear to be absent in implicit tasks. Such findings are consistent with the idea that implicit memory is subserved by a more primitive system that evolves earlier at both phylogenetic and ontogenetic levels. The present paper reviews previous studies that claimed to find evidence that implicit memory is fully developed in very young children. Issues of measurement error, ceiling effects, and insufficient power brought up questions about those studies with respect to the developmental issue. The present study compares performance on implicit (picture fragment completion) and explicit (free recall and recognition) memory tasks with groups ranging in age from 5-28 years. We find a reliable developmental trend in both implicit and explicit performance in which the former cannot be attributed to the operation of explicit memory processes. Thus, we conclude that implicit memory, like explicit memory, develops with age.     

Low Reliability of Perceptual Priming: Consequences for the Interpretation of Functional Dissociations Between Explicit and Implicit Memory

In this study, three experiments are presented that investigate the reliability of memory measures. In Experiment 1, the well-known dissociation between explicit (recall, recognition) and implicit memory (picture clarification) as a function of age in a sample of 335 persons aged between 65 and 95 was replicated. Test-retest reliability was significantly lower in implicit than in explicit measures. In Experiment 2, parallel-test reliabilities in a student sample confirmed the finding of Experiment 1. In Experiment 3, the reliability of cued recall and word stem completion was investigated. There were significant priming effects and a dissociation between explicit and implicit memory as a function of levels of processing. However, the reliability of implicit memory measures was again substantially lower than in explicit tests in all test conditions. As a consequence, differential reliabilities of direct and indirect memory tests should be considered as a possible determinant of dissociations between explicit and implicit memory as a function of experimental or quasi-experimental manipulations.     

The effect of midazolam on implicit and explicit memory in category exemplar production and category cued recall

Transfer-appropriate processing theory (Roediger, Weldon, & Challis, 1989) proposes that dissociations between performance on explicit and implicit memory tests arise because these tests often rely on different types of information processing (e.g., perceptual processing vs conceptual processing). This perspective predicts that implicit and explicit memory tasks that rely primarily on conceptual processing should show comparable results, not dissociations. Numerous studies have demonstrated such similarities. It is, however, possible that these results arise from explicit memory contamination of performance on implicit memory tasks. To address this issue, an experiment was conducted in which participants were administered the sedative midazolam prior to study. Midazolam is known to create a temporary, but dense, period of anterograde amnesia. The effects of blocking stimulus materials by semantic category at study and generation at study were investigated on category exemplar production and category-cued recall. The results of this study demonstrated a dissociation of the effects of midazolam on category exemplar production and category-cued recall. Specifically, midazolam reduced the effect of blocking stimulus materials in category-cued recall, but not in category exemplar production. The differential effect of midazolam on explicit and implicit memory is at odds with transfer-appropriate processing theory and suggests that theories of memory must distinguish the roles of different types of conceptual processing on implicit and explicit memory tests.     

Effect of environmental support on implicit and explicit memory in younger and older adults.

The study addressed 2 major issues: whether there are age differences on an implicit word-stem-completion task and whether age differences on both implicit and explicit memory would decrease with increased environmental support. A total of 287 Ss were presented with words in an incidental learning task with structural or semantic processing. Following 2 filler tasks, Ss received an implicit or an explicit word-stem-completion task. The number of letters in the stem varied from 2 to 4. Results yielded an Age x Memory Task dissociation such that there were large age differences on the explicit task and no age difference on the implicit task, regardless of whether Ss aware of the memory test were included or excluded. There was no evidence that environmental support improved older adults' performance more than that of younger adults on either memory task.     

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.     

内隐和外显记忆的发展研究

采用Buchner等人（1995）提出的加工分离范式的修正模型,对内隐和外显记忆进行分离。结果表明：内隐记忆水平随年龄的变化不大．而外显记忆水平在12岁左右达到高峰;内隐记忆与外显记忆均不具有性别差异。     

The effect of midazolam on implicit and explicit memory in category exemplar production and category cued recall

Transfer‐appropriate processing theory (Roediger, Weldon, & Challis, 1989) proposes that dissociations between performance on explicit and implicit memory tests arise because these tests often rely on different types of information processing (e.g., perceptual processing vs conceptual processing). This perspective predicts that implicit and explicit memory tasks that rely primarily on conceptual processing should show comparable results, not dissociations. Numerous studies have demonstrated such similarities. It is, however, possible that these results arise from explicit memory contamination of performance on implicit memory tasks. To address this issue, an experiment was conducted in which participants were administered the sedative midazolam prior to study. Midazolam is known to create a temporary, but dense, period of anterograde amnesia. The effects of blocking stimulus materials by semantic category at study and generation at study were investigated on category exemplar production and category‐cued recall. The results of this study demonstrated a dissociation of the effects of midazolam on category exemplar production and category‐cued recall. Specifically, midazolam reduced the effect of blocking stimulus materials in category‐cued recall, but not in category exemplar production. The differential effect of midazolam on explicit and implicit memory is at odds with transfer‐appropriate processing theory and suggests that theories of memory must distinguish the roles of different types of conceptual processing on implicit and explicit memory tests.     

DOUBLE DISSOCIATION BETWEEN MEMORY SYSTEMS UNDERLYING EXPLICIT AND IMPLICIT MEMORY IN THE HUMAN BRAIN

Abstract— Amnesic patients have impaired explicit memory that is evident in poor recall and recognition of words, yet can have intact implicit memory for words as measured by repetition priming, the enhanced efficiency for reprocessing those word's. The dissociation between explicit and implicit memory for words is a fundamental characteristic of normal cognition that could reflect two different functional architectures of the human brain two separate processing systems or two levels of operation of a single system with implicit memory less demanding of that system. We present a patient who has a lesion in the right occipital lobe and who showed intact explicit and impaired implicit memory for words. The deficit was specific to visual priming. The double dissociation between explicit and implicit visual memory for words indicates that separate processing systems mediate these two forms of memory, and that a memory system in right occipital cortex mediates implicit visual memory for words.     

Examining the Response Competition Hypothesis of Age Effects in Implicit Memory

ABSTRACT

Age reductions in priming have been explained by differences in processing demands across implicit memory tests. According to one hypothesis, older adults show reduced priming relative to younger adults on implicit tests that require production of a response because these tests typically allow for response competition. In contrast, older adults do not show reductions in priming on identification tests that contain little response competition. The following experiments tested the specific role of response competition in mediating age effects in implicit memory. In Experiment 1, younger and older adults studied a list of words and were then given an implicit test of word stem completion. They studied a second list of words and were given an implicit test of general knowledge. Each implicit test contained items with unique solutions (the low response competition condition) and items with multiple solutions (the high response competition condition). In Experiment 2, younger and older adults were given explicit versions of the word stem completion and the general knowledge tests. Results showed an effect of age on explicit memory (Experiment 2), but no effect of age or response competition on priming (Experiment 1). Results are inconsistent with the theory that response competition leads to age effects on production tests of implicit memory.     

Geographic patterns of implicit age bias and associations with state-level health outcomes across the United States

Negative attitudes toward aging are pervasive in society and may be detrimental to people's health as they become older. Older people tend to report feeling significantly younger than their chronological age, often as a way of psychologically distancing themselves from the stigma of old age. However, attitudes and behaviors toward aging may differ across regional contexts. We examined associations among state-level patterns of bias against older adults and state-level health outcomes across the United States. Data from 803,009 respondents (ages: 15–94) across 50 U.S. states (and the District of Columbia) revealed geographic variation in implicit age bias. Higher state-level implicit age bias was associated with poorer state-level health outcomes among adults ages 65+. Older adults living in states high in implicit age bias showed greater age-group dissociation compared to older adults living in states low in implicit age bias. Findings highlight potential consequences of implicit age bias and invite further research on the long-term health implications of individual age-group dissociation in response to regional age bias.     

The sensorimotor contributions to implicit memory, familiarity, and recollection

The sensorimotor contributions to memory for prior occurrence were investigated. Previous research has shown that both implicit memory and familiarity draw on gains in stimulus-related processing fluency for old, compared with novel, stimuli, but recollection does not. Recently, it has been demonstrated that processing fluency itself resides in stimulus-specific motor simulations or reenactment (e.g., covert pronouncing simulations for words as stimuli). Combining these lines of evidence, it was predicted that stimulus-specific motor interference preventing simulations should impair both implicit memory and familiarity but leave recollection unaffected. This was tested for words as verbal stimuli associated to pronouncing simulations in the oral muscle system (but also for tunes as vocal stimuli and their associated vocal system, Experiment 2). It was found that oral (e.g., chewing gum), compared with manual (kneading a ball), motor interference prevented mere exposure effects (Experiments 1-2), substantially reduced repetition priming in word fragment completion (Experiment 3), reduced the familiarity estimates in a remember-know task (Experiment 5) and in receiver-operating characteristics (Experiment 6), and completely neutralized familiarity measured by self-reports (Experiment 4) and skin conductance responses (Experiment 7), while leaving recollection and free recall unaffected (across Experiments 1-7). This pattern establishes a rare memory dissociation in healthy participants, that is, explicit without implicit memory or recognizing without feeling familiar. Implications for embodied memory and neuropsychology are discussed.     

What colour is the car? Implicit memory for colour information in children

Three experiments were conducted to examine age-related differences in colour memory. In Experiment 1, preschool age and elementary school age children were given a conceptual test of implicit colour memory (a colour-choice task). They were presented with the names or achromatic versions of previously studied coloured line drawings and asked to select an appropriate colour. Significant priming could be demonstrated: The children chose the previously seen colours more often than was expected by chance. Equivalent priming was found for both versions (pictorial and verbal) suggesting that colour priming may be conceptually mediated. Moreover, colour priming proved to be age invariant. Experiment 2 replicated and extended this finding by using a wider age group (preschool, elementary school, and young adults) and by giving a perceptual implicit task (picture identification) in addition to a verbal colour-choice task. Colour did not affect priming in the perceptual task. Whereas priming showed no developmental change, agerelated improvements were observed on an explicit colour memory task that differed only in the test instructions from the implicit colour-choice task (Experiments 2 and 3). Taken together, the results suggest that implicit colour memory may be mediated by conceptual processes that are age invariant.     

社会认知具有更强的内隐性──兼论内隐和外显的“钢筋水泥”关系

采用Ｊａｃｏｂｙ的加工分离程序,对记忆测验中图片的社会性特征与非社会性特征的外显记忆现人隐记忆贡献进行分离,考察了对社会性信息的加工中内隐记忆的贡献是强于对非社会性信息加工的内隐记忆贡献,还是相反。结果表明：对社会性信息的加工中内隐记忆的贡献强于对非社会性信息加工的内隐记忆贡献。另外在本实验研究结果的启发下,提出了内隐和外显记忆的“钢筋水泥”结构性模型的假设。     

Implicit memory and depression: preserved conceptual priming in subclinical depression

Depression impairs explicit memory but research on implicit memory is equivocal. Initial studies indicated preserved implicit memory, implying a depressive deficit in intentional but not unintentional forms of memory. Subsequent research indicated that conceptual priming is reduced in depression, implying a deficit in conceptual memory processes be they implicit or explicit. However, the findings with conceptual priming may be compromised by explicit contamination. The present study compared subclinically depressed and non-depressed participants on matched conceptual tests of explicit memory (category-cued recall) and implicit memory (category production). The implicit test was followed by a post-test questionnaire used to categorise participants as test-aware or test-unaware. On the explicit test, the subclinically depressed participants recalled less than the non-depressed participants. The results on the implicit test depended on test-awareness. Among test-unaware participants, conceptual priming was equivalent across the two groups, whereas for the test-aware, non-depressed participants produced significantly more priming than the subclinically depressed. This indicates that when explicit contamination is controlled, depression does not impair conceptual priming. The depressive dissociation between implicit and explicit memory is better accounted for by the difference between intentional and unintentional forms of memory rather than by the difference between conceptual and perceptual memory processes.     

The Explicit and Implicit Domains in Psychoanalytic Change

New research findings of the development and organization of the mind, brain, and behavior bolster the ongoing relational- or intersubjective-field paradigmatic revision of psychoanalytic theory. A multisystems view of learning, memory, and knowledge provide us with a more complex picture of information processing that has fundamental implications for a psychoanalytic theory of therapeutic action.

If the implicit and explicit learning/memory systems are viewed as parallel processes, not easily translatable from one to the other, then new implicit relational experience carries considerably more power as compared to explicit/declarative processing in changing and establishing new implicit mental models. When these cognitive processing systems are viewed as more closely interconnected with a developmental emphasis on connecting them through language, then exploratory/interpretive work becomes more central. REM, dream, infant, and cognitive research evidence suggests that imagistic symbolic capacity exists at birth. Learning and remembering using imagistic symbolic processing could suggest a more easily translatable connection with later developed verbal symbolic processing and a closer, although varied, interconnection between implicit and explicit (symbolic) memory systems.

Explicit attitudes are more directly modifiable through an explicit/declarative focus. Implicit mental models, it is proposed, are variably modifiable through two different change processes: (1) accommodation or transformation of expectancies through new implicit procedural experience (not requiring explicit focus) and (2) diminished activation and increased capacity to deactivate implicit mental models through explicit/declarative processing and the establishment of contrasting implicit models through new implicit procedural experience.     

Developmental patterns in priming and familiarity in explicit recollection

Developmental trajectories of two classes of human memory, implicit and explicit memory, appear to diverge. We examined how developmental differences in perceptual and conceptual priming, two types of implicit memory, coincide with differences between familiarity and recollective responses on explicit memory tests that employ the Remember/Know paradigm ( Tulving, 1985 ). Both types of priming were characterized by developmental invariance in 52 children and adolescents ages 8-19 years. Contrary to Komatsu, Naito, and Fuke (1996) results, few age-group differences in perceptual priming were observed following a levels-of-processing encoding manipulation. In contrast, age group differences were found for "Remember" but not "Know" responses. Neither levels of awareness nor strategies influenced priming. Adult levels of performance appear earlier in development on perceptual and conceptual priming tests compared to explicit memory tests. Similar developmental dissociations exist between explicit and implicit memory performance as between "Remember" and "Know" recollective responses.     

Measuring automatic retrieval in a conceptual priming task

The speeded response technique has demonstrated that priming in perceptual memory tasks can occur through automatic retrieval that is uncontaminated by conscious retrieval (pure automatic retrieval). This work assesses whether priming in a conceptual task (category exemplar generation) can occur through pure automatic retrieval using the same technique. Automatic retrieval estimates obtained using the speeded response technique were compared to those obtained using more traditional measures (implicit memory and process dissociation procedure [PDP]). Similar estimates of automatic retrieval were obtained for speeded, implicit, and PDP groups following shallow processing. However, higher estimates of automatic retrieval were obtained following deep processing in the speeded and implicit conditions compared to the PDP condition. Advantages for using the speeded response technique to index automatic memory are discussed.     

Involuntary aware memory enhances priming on a conceptual implicit memory task

This study investigated the role of involuntary aware memory (phenomenological awareness of the study episode) on a conceptual implicit memory task. Subjects studied words under levels of processing conditions (LOP: nonsemantic vs. semantic) and then received a category exemplar generation priming task. Subjects were either aware or unaware of the study test relationship. Subjects who were study test aware showed more priming for semantic study than subjects who were study test unaware, thus producing an LOP dissociation between them. The findings suggest that involuntary aware memory can enhance performance on conceptual implicit memory tasks, thus having theoretical implications for implicit and explicit memory.