Effects of dividing attention during encoding on perceptual priming of unfamiliar visual objects

According to the distractor-selection hypothesis (Mulligan, 2003), dividing attention during encoding reduces perceptual priming when responses to non-critical (i.e., distractor) stimuli are selected frequently and simultaneously with critical stimulus encoding. Because direct support for this hypothesis comes exclusively from studies using familiar word stimuli, the present study tested whether the predictions of the distractor-selection hypothesis extend to perceptual priming of unfamiliar visual objects using the possible/impossible object decision test. Consistent with the distractor-selection hypothesis, Experiments 1 and 2 found no reduction in priming when the non-critical stimuli were presented infrequently and non-synchronously with the critical target stimuli, even though explicit recognition memory was reduced. In Experiment 3, non-critical stimuli were presented frequently and simultaneously during encoding of critical stimuli; however, no decrement in priming was detected, even when encoding time was reduced. These results suggest that priming in the possible/impossible object decision test is relatively immune to reductions in central attention and that not all aspects of the distractor-selection hypothesis generalise to priming of unfamiliar visual objects. Implications for theoretical models of object decision priming are discussed.     

Perception and recognition memory of words and werds: Two-way mirror effects

We examined associative priming of words (e.g., TOAD) and pseudohomophones of those words (e.g., TODE) in lexical decision. In addition to word frequency effects, reliable base-word frequency effects were observed for pseudohomophones: Those based on high-frequency words elicited faster and more accurate correct rejections. Associative priming had disparate effects on high- and low-frequency items. Whereas priming improved performance to high-frequency pseudohomophones, it impaired performance to low-frequency pseudohomophones. The results suggested a resonance process, wherein phonologic identity and semantic priming combine to undermine the veridical perception of infrequent items. We tested this hypothesis in another experiment by administering a surprise recognition memory test after lexical decision. When asked to identify words that were spelled correctly during lexical decision, the participants often misremembered pseudohomophones as correctly spelled items. Patterns of false memory, however, were jointly affected by base-word frequencies and their original responses during lexical decision. Taken together, the results are consistent with resonance accounts of word recognition, wherein bottom-up and top-down information sources coalesce into correct, and sometimes illusory, perception. The results are also consistent with a recent lexical decision model, REM-LD, that emphasizes memory retrieval and top-down matching processes in lexical decision.     

非熟练中—英双语者跨语言长时重复启动效应

采用跨语言长时重复启动研究范式进一步探讨非熟练中－英双语者的记忆表征模型。被试为华南师范大学大一本科生共140名。实验自变量是语言条件（同语言和跨语言）和学习状况（学习过的和未学习过的）,实验因变量是单词判断的反应时和正确率。实验1中被试在学习和测验阶段都完成概念任务,结果表明获得了跨语言长时重复启动效应。实验2中被试在学习和测验阶段完成词汇任务,结果表明没有获得跨语言长时重复启动效应。实验3中被试在学习阶段完成概念任务,在测验阶段完成词汇任务,结果表明没有获得跨语言长时重复启动效应。实验4中在学习阶段的概念任务中呈现汉语单字词,在测验阶段的词汇任务中呈现英语翻译对等词,结果表明没有获得跨语言长时重复启动效应。总的实验结果表明,在基于内隐记忆的跨语言重复启动的范式下,非熟练中－英双语者的记忆表征支持概念表征共享、词汇表征分离的观点。更重要的是,非熟练中－英双语者需要经由汉语翻译对等词的词汇表征,才能通达英语单词的概念表征,支持了词汇连接模型的观点     

内隐记忆研究的实验方法探索：启动效应计量方法的改进思路及其实验研究

以实验鉴定了常规的启动效应计量方法的有效性程度,并为客观地计量启动效应,创用了“超意识广度法”、“二次比较法”等．结果发现：（１）如被试数量较少,以不同补笔率为“基线值”所求得的启动效应之间发生显著差异的可能性存在;（２）超意识广度法能克服“阈下呈现刺激法”“分散注意法”的不足,为内隐记忆提供有利的识记情境;（３）“二次比较法”能为正常人内隐记忆的存在提供更为直接、可靠的证据,并能客观、精确地计量启动效应。     

Development of memory structures for homographs using pathfinder network representations

Some studies with children have shown that there is no semantic priming at short stimulus onset asynchrony (SOA) in lexical decision and naming tasks for homographs. The predictions of spreading activation theories might explain this missing effect. There may be differences in children's and adults' memory structures. We have explored this hypothesis. The development of memory structure representations for homographs was measured by a Pathfinder algorithm. In Experiment 1, the three dependent variables were: the number of links in the network, closeness measures (C), and distances between nodes. Results revealed developmental differences in network structure representations in adults and children. In Experiment 2, results revealed that these differences were not due to the cohort effect. In Experiment 3, the relationship between associative strength, as measured by associative norms, and distances, as measured by Pathfinder algorithm, was explored. The results of these three experiments and empirical research from semantic priming experiments show that these differences in memory structure representations could be one of the sources of the missing semantic priming effect in children.     

Is masked priming modulated by memory load? A test of the automaticity of masked identity priming in lexical decision

One of the key assumptions of the masked priming lexical decision task (LDT) is that primes are processed without requiring attentional resources. Here, we tested this assumption by presenting a dual-task manipulation to increase memory load and measure the change in masked identity priming on the targets in the LDT. If masked priming does not require attentional resources, increased memory load should have no influence on the magnitude of the observed identity priming effects. We conducted two LDT experiments, using a within-subjects design, to investigate the effect of memory load (via a concurrent matching task Experiment 1 and a concurrent search task in Experiment 2) on masked identity priming. Results showed that the magnitude of masked identity priming on word targets was remarkably similar under high and low memory load. Thus, these experiments provide empirical evidence for the automaticity assumption of masked identity priming in the LDT.     

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。     

The Role of Semantic Features in Verb Processing

The present study examined the general hypothesis that, as for nouns, stable representations of semantic knowledge relative to situations expressed by verbs are available and accessible in long term memory in normal people. Regular associations between verbs and past tenses in French adults allowed to abstract two superordinate semantic features in the representation of verb meaning: durativity and resultativity. A pilot study was designed to select appropriate items according to these features: durative, non-resultative verbs and non-durative, resultative verbs. An experimental study was then conducted to assess semantic priming in French adults with two visual semantic-decision tasks at a 200- and 100-ms SOA. In the durativity decision task, participants had to decide if the target referred to a durable or non-durable situation. In the resultativity decision task, they had to decide if it referred to a situation with a directly observable outcome or without any clear external outcome. Targets were preceded by similar, opposite, and neutral primes. Results showed that semantic priming can tap verb meaning at a 200- and 100-ms SOA, with the restriction that only the positive value of each feature benefited from priming, that is the durative and resultative values. Moreover, processing of durativity and resultativity is far from comparable since facilitation was shown on the former with similar and opposite priming, whereas it was shown on the latter only with similar priming. Overall, these findings support Le Ny’s (in: Saint-Dizier, Viegas (eds) Computational lexical semantics, 1995; Cahier de Recherche Linguistique LanDisCo 12:85–100, 1998; Comment l’esprit produit du sens, 2005) general hypothesis that classificatory properties of verbs could be interpreted as semantic features and the view that semantic priming can tap verb meaning, as noun meaning.     

The recency effect: Implicit learning with explicit retrieval?

The recency effect in free recall features prominently in 1960s' theorizing about short-term memory, but has since been largely ignored. We argue that this stems from a preoccupation with the role of recency in the concept of primary memory and the neglect of its role in a broader working-memory framework. It is suggested that the recency effect reflects the application of an explicit retrieval strategy to the residue of implicit learning within a range of cognitive systems. When retrieved implicitly, the same residue is assumed to form the basis of priming effects. The various criteria for implicit learning described by Tulving and Schacter (1990) are successfully applied to the recency effect, and a retrieval process is outlined that can account for both long- and short-term recency effects. It is suggested that a framework combining recency, priming, and implicit learning provides a basis for understanding one of the most important features of cognition and memory, namely, that of maintaining orientation in time and place.     

Using the memory activation capture (MAC) procedure to investigate the temporal dynamics of hypothesis generation

Research investigating top-down capture has demonstrated a coupling of working memory content with attention and eye movements. By capitalizing on this relationship, we have developed a novel methodology, called the memory activation capture (MAC) procedure, for measuring the dynamics of working memory content supporting complex cognitive tasks (e.g., decision making, problem solving). The MAC procedure employs briefly presented visual arrays containing task-relevant information at critical points in a task. By observing which items are preferentially fixated, we gain a measure of working memory content as the task evolves through time. The efficacy of the MAC procedure was demonstrated in a dynamic hypothesis generation task in which some of its advantages over existing methods for measuring changes in the contents of working memory over time are highlighted. In two experiments, the MAC procedure was able to detect the hypothesis that was retrieved and placed into working memory. Moreover, the results from Experiment 2 suggest a two-stage process following hypothesis retrieval, whereby the hypothesis undergoes a brief period of heightened activation before entering a lower activation state in which it is maintained for output. The results of both experiments are of additional general interest, as they represent the first demonstrations of top-down capture driven by participant-established WM content retrieved from long-term memory.     

Repetition priming in picture naming: sustained learning through the speeding of multiple processes

Picture naming has been used by vision researchers to study object identification, by language researchers to study word production, and by memory researchers to study implicit memory. Response times for naming repeated pictures decrease with successive repetitions. Repetition priming in picture naming involves an implicit, nonhippocampal form of memory. In this review, the processes speeded with repetition are decomposed, the time course of the effect is characterized, the factors affecting the magnitude of priming are enumerated, and possible mechanisms of priming are evaluated. Both behavioral response time and neuroimaging studies are considered. The processes that are speeded with repetition include high-level object identification and word production processes, but not low-level visual processes or articulation. Repetition priming lasts for at least several weeks and follows a typical forgetting function. The mechanism of priming is concluded to be speeded completion of the component processes of picture naming.     

A rational approach to memory search termination

An important component of many, if not all, real-world retrieval tasks is the decision to terminate memory search. Despite its importance, systematic evaluations of the potential rules for terminating search are scarce. Recent work has focused on two variables: the total time spent in memory search before search is terminated and the exit latency (the time between the last retrieved item and the time of search termination). These variables have been shown to limit the number of plausible rules for terminating memory search. Here, we introduce an alternative stopping rule based on a rational moment-to-moment cost–benefit analysis and derive a closed-form expression of the exit latency function using this rational approach. We show the model’s ability to capture critical latency data and make testable predictions about the influence of changing the relative costs and benefits of memory search. Results from an experiment are presented that support the model’s predictions. We conclude that the decision to terminate memory search is based on moment-to-moment changes in subjective utility of retrieved memories.     

Being forward not backward: lexical limits to masked priming

This study investigated whether masked priming is mediated by existing memory representations by determining whether nonwords targets would show repetition priming. To avoid the potential confound that nonword repetition priming would be obscured by a familiarity response bias, the standard lexical decision and naming tasks were modified to make targets unfamiliar. Participants were required to read a target string from right to left (i.e., "ECAF" should be read as "FACE") and then make a response. To examine if priming was based on lexical representations, repetition primes consisted of words when read forwards or backwards (e.g., "face", "ecaf") and nonwords (e.g., "pame", "emap"). Forward and backward primes were used to test if task instruction affected prime encoding. The lexical decision and naming tasks showed the same pattern of results: priming only occurred for forward primes with word targets (e.g., "face-ECAF"). Additional experiments to test if response priming affected the LDT indicated that the lexical status of the prime per se did not affect target responses. These results showed that the encoding of masked primes was unaffected by the novel task instruction and support the view that masked priming is due to the automatic triggering of pre-established computational processes based on stored information.     

False memories and lexical decision: even twelve primes do not cause long-term semantic priming

Semantic priming effects are usually obtained only if the prime is presented shortly before the target stimulus. Recent evidence obtained with the so-called false memory paradigm suggests, however, that in both explicit and implicit memory tasks semantic relations between words can result in long-lasting effects when multiple 'primes' are presented. The aim of the present study was to investigate whether these effects would generalize to lexical decision. In four experiments we showed that even as many as 12 primes do not cause long-term semantic priming. In all experiments, however, a repetition priming effect was obtained. The present results are consistent with a number of other results showing that semantic information plays a minimal role in long-term priming in visual word recognition.     

Semantic priming in young and older adults: evidence for age constancy in automatic and attentional processes

Automatic and attentional components of semantic priming and the relation of each to episodic memory were evaluated in young and older adults. Category names served as prime words, and the relatedness of the prime to a subsequent lexical decision target was varied orthogonally with whether the target category was expected or unexpected. At a prime-target stimulus-onset asynchrony (SOA) of 410 ms, target words in the same category had faster lexical decision latencies than did different category targets. This effect was not significant at a 1,550-ms SOA and was attributed to automatic processes. Expected category targets had faster latencies than unexpected category targets at the 410-ms SOA, and the magnitude of the effect increased at the 1,550-ms SOA. This effect was attributed to attentional processes. These patterns of priming were obtained for both age groups, but in a surprise memory test older adults had poorer recall of primes and targets. We discuss the implications of these results for the hypothesis that older adults suffer deficits in selective attention and for the related hypothesis that attentional deficits impair semantic processing, which causes memory decrements in old age.     

Neuropsychological dissociations between priming and recognition: a single-system connectionist account

A key claim of current theoretical analyses of the memory impairments associated with amnesia is that certain distinct forms of learning and memory are spared. A compelling example is that amnesic patients and controls are indistinguishable in repetition priming but amnesic patients are impaired at recognizing the study items. The authors show that this pattern of results is predicted by a single-system connectionist model of learning in which amnesia is simulated by a reduced learning rate. They also demonstrate that the model can reproduce the converse pattern in which priming but not recognition is impaired if the input is assumed to be additionally degraded in a priming test. The authors conclude that dissociations between priming and recognition do not require functionally or neurally distinct memory systems.     

Dissociating perceptual and conceptual implicit memory in multiple sclerosis patients

Previous studies indicate that Multiple Sclerosis (MS) patients exhibit deficits in tests of explicit memory such as free recall, but show normal priming on implicit tests of memory such as word stem completion. However, the memory performance of patients with different MS disease subtypes has not been fully examined. In the current study, memory was assessed in Primary Progressive (PPMS), Relapsing Remitting (RRMS), and Secondary Progressive (SPMS) MS subgroups. Explicit memory as well as perceptual and conceptual implicit memory were examined using free recall, word fragment completion, and exemplar generation tests, respectively. All three groups of MS patients exhibited free recall deficits and normal priming on the exemplar generation test. However, the PPMS group exhibited a deficit in word fragment completion priming, whereas the RRMS and SPMS groups exhibited normal levels of priming on this task. Lesion load was assessed using magnetic resonance imaging and was negatively correlated with explicit memory performance, but it did not account for the observed deficits in perceptual implicit memory. The results indicate that PPMS patients exhibit a pattern of memory impairment that is distinct from that of the RRMS and SPMS groups. Moreover, the results indicate that perceptual implicit memory can be neurologically dissociated from conceptual implicit memory.     

Are words represented by nodes?

Semantic priming in a lexical decision task was investigated with concurrent pretarget and posttarget primes. The posttarget prime also served as a pattern mask of the lexical decision target. Forward priming is defined as the presence of a semantically related pretarget prime and an unrelated posttarget prime. Backward priming is defined as the presence of a semantically related posttarget prime and an unrelated pretarget prime. Forward and backward priming were compared both when the nonword foils were "legal" and when they were "illegal" with respect to English orthography. Predictions were derived for two general approaches to word recognition: spreading-activation and expectancy-set theories. Both approaches assume that word representations occupy distinct, nonoverlapping locations in memory. Backward-prime facilitation was equivalent to forward-prime facilitation when nonword foils were illegal; however, backward-prime facilitation was not significant when nonword foils were legal. These results challenge both approaches. The proposed solution uses semantic-space (distributed) representations that are functionally unitized by a resonant matching (verification) process.