Perceptual implicit memory requires attentional encoding

Perceptual implicit memory for previously attended and unattended words was measured either in a word-stem completion task or in a perceptual fluency (perceptual identification) task. Subjects (N = 144) first engaged in a focused attention task in which they were to identify one of two words presented for 100, 200, or 300 msec. Words were classified as attended if they were reported during the focused attention task and unattended if they were not. Results for both implicit memory tests indicated reliable perceptual implicit memory for attended words but not for unattended words, regardless of focused attention exposure duration. The results indicate that perceptual implicit memory tasks reflect attentional encoding processes; that is, words must undergo attentional encoding if they are to affect performance on a later perceptual implicit memory test.     

Implicit Memory and Anxiety: Perceptual Identification of Emotional Stimuli

The perceptual identification paradigm was used to examine implicit memory performance in high- and low-trait anxious subjects. A series of threat-related and neutral words was presented in different colours during the encoding phase. Subjects were required to encode the stimuli by naming the colour while ignoring the semantic content of the words (Experiment 1), by simply reading the words (Experiment 2) or by naming the colour of the words and the words themselves (Experiment 3). Experiment 1 demonstrated the predicted emotional Stroop effect, with high-trait subjects taking relatively longer than low-trait subjects to name the colour of the threat-related as compared to the neutral stimuli. All three experiments revealed a significant implicit memory effect overall, with more primed than unprimed words being correctly identified during the perceptual identification task. Subjects in all experiments also identified more of the threat-related than neutral words. Although Experiment 2 found that, overall, the high-trait subjects identified relatively fewer threat-related words than neutral words in comparison to the low-trait subjects, none of the experiments offered any support for the prediction of a threat-related implicit memory bias in hightrait anxiety.     

Stimulus exposure time and perceptual memory

The recent explosion of research on implicit memory has facilitated the examination of perceptual and conceptual processes in the encoding of information. Nevertheless, stimulus exposure time—the amount of time that a stimulus is physically available to a perceiver’s scrutiny—has received little attention. In the present paper, we examine the effect of stimulus exposure time on three implicit memory measures (word-fragment completion, perceptual identification, and general knowledge) and two explicit memory measures (graphemic cued recall and semantic cued recall). In Experiment 1, we demonstrated that increases in exposure time lead to increases in implicit perceptual memory, but not to implicit conceptual memory, when the encoding task focuses on perceptual features of the stimulus. We replicated this effect in Experiment 2 and demonstrated that increases in exposure time lead to increases in perceptualand conceptual memory when the measures are explicit. Thus, the current experiments demonstrate that manipulations of exposure time lead to dissociations in implicit, but not explicit, memory.     

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。     

Implicit memory in spelling from word images

Summary A series of experiments is reported concerning implicit memory in imaginal processing. In the standard condition, subjects had to encode word images before spelling a word. The spelling task was repeated in the test phase with the same words and with additional control words. Spelling times were registered after the image encoding. Implicit memory has been detected if repeated words can be spelled faster than control words. Experiment 1 showed that levels of processing manipulations (such as the additional generation of meaning images at encoding or variations in word concreteness) favor explicit memory, but do not show up in implicit memory. Experiment 2 demonstrated that implicit memory disappears if spelling at encoding took place on visually present words. Experiment 3 investigated whether the focusing of specific letter positions within the image may contribute to the effect, but this was not found. According to a processing view that underlies our task analysis, implicit memory depends on transfer-appropriate processing and is attributed to processes of image encoding or generation and image reconstruction or regeneration.     

Perceptual specificity and implicit auditory priming in older and younger adults.

Age differences in perceptual specificity for implicit auditory priming were examined in 3 experiments. All 3 experiments began with a study phase during which participants rated words based on perceptual (shallow encoding) or semantic (deep encoding) attributes. After the study phase, participants were asked to identify filtered versions of repeated and new words (implicit test) and then to make old/new recognition judgments (explicit test). In contrast to earlier findings (D. L. Schacter, B. Church, & D. M. Osowiecki, 1994), older and younger adults were equally sensitive to study-to-test changes in speaking rate (Experiment 1), fundamental frequency (Experiment 2), and voice (Experiment 3). Explicit memory, in contrast, was significantly poorer for older adults but was minimally affected by changes in surface features. Findings from the study are discussed with respect to their implications for establishing the mechanisms mediating perceptual specificity and for their importance in understanding age-related changes in implicit memory.     

Effects of hearing words, imaging hearing words, and reading on auditory implicit and explicit memory tests

In four experiments, we examined the degree to which imaging written words as spoken by a familiar talker differs from direct perception (hearing words spoken by that talker) and reading words (without imagery) on implicit and explicit tests. Subjects first performed a surface encoding task on spoken, imagined as spoken, or visually presented words, and then were given either an implicit test (perceptual identification or stem completion) or an explicit test (recognition or cued recall) involving auditorily presented words. Auditory presentation at study produced larger priming effects than did imaging or reading. Imaging and reading yielded priming effects of similar magnitude, whereas imaging produced lower performance than reading on the explicit test of cued recall. Voice changes between study and test weakened priming on the implicit tests, but did not affect performance on the explicit tests. Imagined voice changes affected priming only in the implicit task of stem completion. These findings show that the sensitivity of a memory test to perceptual information, either directly perceived or imagined, is an important dimension for dissociating incidental (implicit) and intentional (explicit) retrieval processes.     

Contribution of perceptual fluency to recognition judgments.

Following a shallow (count vowels) or deep (read) study task, old and new words were tested for both fluency of perception and recognition memory. Subjects first identified a test word as it came gradually into view and then judged it as old or new. Old words were identified faster than new words, indicating implicit, perceptual memory for old words. Independently of this effect, words judged old were identified faster than words judged new, especially after shallow study. Eight experiments examined the possible causal relationship between perceptual fluency and recognition judgements. Experiments 1 to 4 showed that fast identifications per se do not promote old judgments. Accelerating the identification of test items by semantically priming them or making them come more quickly into view did not affect recognition judgments. Experiment 5 showed that the usual association of fast identifications with old judgments is not an artifact of item selection because the association disappeared when the identifications and judgements were segregated into different phases of the test task. Experiments 6 and 7 showed tha the likelihood of old judgments increases directly with the pretested perceptibility of test words, but only after shallow study. Experiment 8 showed that the dependency of recognition judgments on perceptual fluency continues to hold when the requirement to identify the words before judging them is eliminated. We conclude that fluency of perception contributes to recognition judgments, but only when the fluency is produced naturally (e.g., through perceptual memory) and explicit memory is minimal.     

The effects of divided attention on auditory priming

Traditional theorizing stresses the importance of attentional state during encoding for later memory, based primarily on research with explicit memory. Recent research has begun to investigate the role of attention in implicit memory but has focused almost exclusively on priming in the visual modality. The present experiments examined the effect of divided attention on auditory implicit memory, using auditory perceptual identification, word-stem completion and word-fragment completion. Participants heard study words under full attention conditions or while simultaneously carrying out a distractor task (the divided attention condition). In Experiment 1, a distractor task with low response frequency failed to disrupt later auditory priming (but diminished explicit memory as assessed with auditory recognition). In Experiment 2, a distractor task with greater response frequency disrupted priming on all three of the auditory priming tasks as well as the explicit test. These results imply that although auditory priming is less reliant on attention than explicit memory, it is still greatly affected by at least some divided-attention manipulations. These results are consistent with research using visual priming tasks and have relevance for hypotheses regarding attention and auditory priming.     

Cross-modal priming and explicit memory in patients with verbal production deficits

Implicit memory is often thought to reflect an influence of past experience on perceptual processes, yet priming effects are found when the perceptual format of stimuli changes between study and test episodes. Such cross-modal priming effects have been hypothesized to depend upon stimulus recoding processes whereby a stimulus presented in one modality is converted to other perceptual formats. The present research examined recoding accounts of cross-modal priming by testing patients with verbal production deficits that presumably impair the conversion of visual words into auditory/phonological forms. The patients showed normal priming in a visual stem completion task following visual study (Experiment 1), but showed impairments following auditory study in both implicit (Experiment 2) and explicit (Experiment 3) stem completion. The results are consistent with the hypothesis that verbal production processes contribute to the recoding of visual stimuli and support cross-modal priming. The results also indicate that shared processes contribute to both explicit memory and cross-modal implicit memory.     

Effects of working memory load on long-term word priming

Three experiments assessed the role of verbal and visuo-spatial working memory in supporting long-term repetition priming for written words. In Experiment 1, two priming tasks (word stem completion and category-exemplar production) were included with three levels of load on working memory: (1) without memory load, (2) memory load that involved storing a string of six digits, and (3) memory load that involved storing a graphic shape. Experiments 2 and 3 compared the effects of a verbal (Experiment 2) or a visual (Experiment 3) working memory load at encoding on both an implicit (word stem completion) and an explicit test (cued recall). The results show no effect of memory load in any of the implicit memory tests, suggesting that priming does not rely on working memory resources. By contrast, loading working memory at encoding causes a significant disruptive effect on the explicit memory test for words when the load is verbal but not visual.     

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.     

The fate of originally presented surface information following recall errors in sentence memory tasks

Pictures are remembered better than their names. This picture superiority effect in episodic memory has been attributed either to the greater sensory distinctiveness of pictures or to their greater conceptual distinctiveness. Weldon and Coyote (1996) tested the conceptual distinctiveness hypothesis by comparing how well pictures as opposed to words primed in two conceptual implicit memory tasks (category production and word association). They found no picture superiority in priming and concluded that the basis of the picture superiority effect must then be pictures' greater sensory distinctiveness. Using the same logic, we compared how well pictures as opposed to words primed in a perceptual implicit memory task (picture and word fragment identification). The sensory distinctiveness theory would predict that pictures should prime picture fragment identification better than words prime word fragment identification, a result we call the picture superiority in within-form priming. Across three experiments which manipulated the encoding task at study, only one showed picture superiority in within-form priming. In contrast, in all three experiments there was robust picture superiority in recall, and exposure to pictures and words at study and test produced independent effects in which both study and test exposure to pictures was more effective for recall than exposure to words. We consider how these results might be reconciled by differences in retrieval demands between recall and fragment identification.     

IMPLICIT MEMORY IN AMNESIC PATIENTS:

Abstract— Previous observations of spared priming in amnesic patients have been based almost entirely on data from visual implicit memory tests Our research examined perceptual priming.in amnesic patients and control subjects on an auditory identification task in which previously spoken words and new words were presented in white noise We manipulated type of encoding task (semantic vs nonsemantic) and speaker's voice at study and test (same vs different) Priming was little affected.by either manipulation, and amnesic patients exhibited normal priming in all experimental conditions On an explicit test of recognition memory, by contrast, amnesic patients exhibited.severely impaired performance following the semantic study task, all subjects showed poor explicit memory following the nonsemantic study task Results are consistent with the idea that auditory priming depends largely on a presemantic auditory perceptual representation system     

Effects of working memory load on long‐term word priming

Three experiments assessed the role of verbal and visuo‐spatial working memory in supporting long‐term repetition priming for written words. In Experiment 1, two priming tasks (word stem completion and category‐exemplar production) were included with three levels of load on working memory: (1) without memory load, (2) memory load that involved storing a string of six digits, and (3) memory load that involved storing a graphic shape. Experiments 2 and 3 compared the effects of a verbal (Experiment 2) or a visual (Experiment 3) working memory load at encoding on both an implicit (word stem completion) and an explicit test (cued recall). The results show no effect of memory load in any of the implicit memory tests, suggesting that priming does not rely on working memory resources. By contrast, loading working memory at encoding causes a significant disruptive effect on the explicit memory test for words when the load is verbal but not visual.     

Prospective Memory and Divided Attention

In three experiments, we manipulated the processing demands of a concurrent task to test the hypothesis that an event-based prospective memory task satisfies a criterion of automaticity proposed by Hasher and Zacks (1979). As in the previous studies, a prospective memory task (pressing a key whenever a target word was presented) was embedded within a short-term memory task (remembering seven words). In addition, participants performed a concurrent memory task which varied in difficulty. Participants repeated either 0 to 6 randomly generated digits or a single word. In all three experiments, short-term memory performance was influenced by the concurrent memory load. Prospective performance, in contrast, was not affected by the memory load even though an attempt was made to increase the difficulty of the prospective task by manipulating the specificity of the target instructions (Experiment 2) and the number of target words (Experiments 2 and 3). The results are discussed within the framework of automatic processing.     

Voice-specificity effects on auditory word priming

This research explores the nature of the memory traces that support spoken word identification. Specifically, do voice-specificity effects in implicit memory depend on information in a perceptual representational system or, alternatively, on the similarity of study and test exemplars? Memory for words and voices was assessed with two perceptual identification tests—the identification of words in noise and the identification of low-pass filtered words—after two encoding conditions (identification of words in noise and of words in the clear). At test, a word was presented in the same voice as at study or in a different voice. The data from the two experiments showed that study-to-test changes in voice reduced priming and that voice-specificity effects were greatest when the type of processing engaged at study overlapped with that required at test. Taken together, the results implicate the goodness of the processing match between encoding and test as the primary determinant of voice-specificity effects on perceptual identification tests and support the hypothesis that both voice and word information is represented within a single episodic memory system.     

编码与提取干扰对内隐和外显记忆的非对称性影响

以往研究表明在外显记忆中,编码与提取加工存在着非对称性,但在内隐记忆中,二者的关系并不明确,因此实验采用“学习-再认”范式,考察在编码或提取中分别附加的干扰任务对词汇判断或再认产生的影响。结果证实编码与提取干扰对内隐或外显记忆都具有非对称性的影响,但又存在着差异,即编码干扰会导致随后外显记忆成绩显著减少,而提取干扰对其影响较小,相反,编码干扰对随后内隐测验中启动效应的影响较小,但提取干扰会破坏启动效应,从而为内隐记忆和外显记忆的分离提供了进一步的证据     

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.     

Priming on verbal perceptual tests: Roles of lexical,surface, and conceptual processes

According to a lexical-access hypothesis, priming on verbal-completion tests requires previous access to higher-order nodes such as morphemes or words. In two experiments, subjects studied words presented in printed color, either by reading the words or by naming the printed colors. In Experiment 2, some of the words were to be ignored in both study conditions. The words presented in Experiment 2 were either conceptually related or unrelated to each other. And the cues in the test phase for repeated targets were either printed in the studied color or in a different color. In both experiments, the word stems of nouns studied and of new targets were presented with word-completion instructions (implicit test of memory). Consistent with the hypothesis, the amount of priming obtained was greater in the reading than in the color-naming condition. The least amount of priming was observed for targets that were to be ignored at study. In addition, Experiment 2 showed considerable effects of surface similarity (i.e., stronger priming effects with cues whose color was not changed from the study to the test phase) and some effects of conceptual processing, as was indicated by different amounts of priming for unrelated and for related nouns. Because these two effects were observed with both types of study task, it is concluded that perceptual and conceptual processes may make independent contributions to priming effects in verbal perceptual tests. This conclusion modifies and extends the original hypothesis, according to which previous lexical access is required in order to obtain effects of perceptual or conceptual processes on the priming scores.