Levels of selection and capacity limits.

Examined the effects of word relevancy (word in relevant or irrelevant location) and display load (1–4 words) on physical, semantic, and controlled processing of nontargets in visual target-detection tasks administered to 300 undergraduates in 8 experiments. Interwoven with the detection task was a test-word identification task that was used to measure priming potency of nontargets. Physical and semantic levels of processing were measured in terms of identity and semantic priming, respectively. Nontarget primes were repeated as test words in identity priming. Nontarget primes were semantic associates of test words in semantic priming. Controlled processing of nontargets was measured in terms of recognition memory on a subsequent test. All measures increased with word relevancy and decreased with display load. The priming effects remained intact even when word presentation was speeded up and controlled processing was sharply curtailed. Data indicate that all levels of processing are selective and capacity limited. (60 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic priming and Stroop-like interference in word-naming tasks.

Three studies with 72 undergraduates examined why a semantic relation between relevant and irrelevant stimulus components facilitates performance in priming tasks but seems to inhibit performance in Stroop-like tasks. In a series of word-naming tasks, the effect of number of semantic domains (varied concomitantly with number of response alternatives) was examined by presenting to Ss an identical set of stimuli either blocked or mixed. Exp I showed that blocked presentation yielded Stroop-like interference, whereas mixed presentation yielded semantic facilitation. Exps II and III showed that the word–word variant of the Stroop task and the word-naming variant of the semantic priming task belonged to 1 family of tasks. Both tasks showed a facilitation effect when the prime was related to the target and an interference effect when the prime was a member of the response set. In the Stroop task, response competition outweighed facilitation; in the priming task, semantic facilitation outweighed response competition. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of target–distractor relationships in guiding attention and the eyes in visual search.

Current models of visual search assume that visual attention can be guided by tuning attention toward specific feature values (e.g., particular size, color) or by inhibiting the features of the irrelevant nontargets. The present study demonstrates that attention and eye movements can also be guided by a relational specification of how the target differs from the irrelevant distractors (e.g., larger, redder, darker). Guidance by the relational properties of the target governed intertrial priming effects and capture by irrelevant distractors. First, intertrial switch costs occurred only upon reversals of the coarse relationship between target and nontargets, but they did not occur when the target and nontarget features changed such that the relation remained the same. Second, irrelevant distractors captured most strongly when they differed in the correct direction from all other items—despite the fact that they were less similar to the target. This suggests that priming and contingent capture, which have previously been regarded as prime evidence for feature-based selection, are really due to a relational selection mechanism. Here I propose a new relational vector account of guidance, which holds promise to synthesize a wide range of different findings that have previously been attributed to different mechanisms of visual search. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Input and central processing expressed in ERP and heart rate changes to rare target and rare nontarget stimuli

Whether late positive components of event-related potentials (ERPs) parallel changes in heart rate (HR) indicative of attention/orienting to rare stimuli has been debated. In the present study, a three-stimulus design was used, with rare target, rare nontarget, and frequent standard stimuli delivered under identical conditions except that instructions to subjects described the targets to which subjects should respond but did not describe the nontargets. In Experiment 1, stimuli varied among modalities; in Experiment 2, auditory stimuli were employed. Both ERPs and HR were consistent with automatic processing preceding two stages of controlled processing. Rare stimuli evoked larger parietal P300 and initial HR deceleration than standards. Presumably because of load-reducing effects of long interstimulus intervals, targets and nontargets were not distinguished before a late slow wave and a late phase of HR acceleration. Neither rare stimulus elicited a recognizable frontal P3a.     

Automatic semantic priming: Effect of category exemplar level and word association level.

Evaluated semantic priming when the prime was masked below naming threshold and the target was named in 4 experiments with 263 undergraduates. Exp I showed that when word primes were masked and word targets were named, prior knowledge of the related pairs did not alter semantic priming. Semantic priming within categories occurred only when the prime stimulus was the 1st category exemplar. Findings of Exp II indicate that when masked pictures were used as primes, semantic priming for word targets was sensitive to the category exemplar level of the prime but not to the category exemplar level of the target. Word association norms collected in Exp III did not support the hypothesis that the effect of category exemplar level was mediated by the strength of word association. Exp IV revealed significant semantic priming for masked picture primes and within-category word targets, regardless of the level of word association between prime and target. Exp IV also demonstrated semantic priming for high word association targets that were not members of the same semantic category. For all experiments, Ss with the longest average reaction times (RTs) also showed the largest semantic priming effect for naming word targets. It is suggested that viewing one of the highest ranking category exemplars activates the memory representation of the category, perhaps because such prototypic exemplars are contained within the category concept itself. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming effects in schizophrenia: Associative interference and facilitation as a function of visual context.

Irrelevant stimuli that flank a fixated target may cause either facilitation or interference with target classification. 20 schizophrenic patients, 20 depressed control patients, and 20 normal control Ss were compared on a flanker priming task that involved the linear display of a target surrounded by 2 flanking letters or digits. Choice reaction time (RT) between letter and digit targets was examined as a function of flanker condition and onset asynchrony between flankers and target. Facilitative priming occurred only with prior exposure of flankers compatible with the response required and was greater in degree with schizophrenic and depressed than with normal Ss. Interference from flankers incompatible with the response required occurred less among schizophrenics than among other groups. Several different processes may be involved in the inhibition of irrelevant information by schizophrenics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanisms of unconscious priming: I. Response competition, not spreading activation.

Four experiments were conducted to replicate and expand upon A. G. Greenwald, S. C. Draine, and R. L. Abram's (1996) demonstration that unconsciously perceived priming words can influence judgments of other words. The present experiments manipulated 2 types of relationships between priming and target stimuli: (a) whether priming and target stimuli possess a preexisting semantic relationship (an affective relationship in Experiments 1, 2, and 4; an associative relationship in Experiment 3; and an animacy relationship in Experiment 4) and (b) whether the primes and targets produce the same response. Large priming effects were found only when the primes and targets possessed response compatibility. No residual effects for affective, animacy, or semantic relatedness were observed. Although these results strongly support the conclusion that word meaning can be unconsciously activated, they do not support the claim that the unconscious perception effects obtained in Greenwald et al.'s (1996) paradigm are caused by automatic spreading activation of word meaning. Instead, the results reported here are consistent with a claim that unconsciously perceived words automatically trigger response tendencies that facilitate or interfere with target responding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New limits to automaticity: Context modulates semantic priming.

It is widely assumed that semantic priming in visual word recognition is automatic when the task requires word-level analysis. The present experiments show that this conclusion is too strong. Whether brief-duration primes facilitated the processing of related targets in lexical decision depended on the context in which the primes were seen. Semantic priming occurred if Ss saw only brief primes (blocked condition) but was minimal if longer primes were presented as well (mixed condition). Converging operations indicate that this modulation of semantic priming reflects operations beyond the lexical level rather than early encoding deficits. Rather than being automatic, semantic priming depends on the context in which a word is read. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective attention to global and local structure of objects: alternative measures of nontarget processing

When individuals are asked to report either the global or the local level of structure in a stimulus pattern located inside a relevant object, distractors located within an irrelevant object will interfere only if they are at the same level of structure as that of the target item (Briand, 1993; Paquet & Merikle, 1988). The basis of this level-specific filtering is unclear, as is the true level of semantic analysis for the ignored items. In the present series of experiments, multiple measures of nontarget processing were used to assess concurrent interference, negative priming, and a category effect supposedly reflecting a more abstract level of semantic analysis. These different indicants were assessed in three experiments in which form, color, or a spatial precue was used to direct attention to the relevant stimulus pattern. Overall, cuing by form produced poorer spatial selectivity, whereas spatial precues and color led to better selectivity. However, the three measures of nontarget processing were not equally affected by these manipulations, with global information showing more evidence for semantic analysis than for local analysis regardless of the type of selection cue used. The results suggest that inhibition is not the basis of target selection when ignored items are local, but that it may be used when global items are ignored.     

Attention and semantic priming: a review of prime task effects

The single-word semantic priming paradigm is a tool for investigating how and when word meaning (semantic) activation occurs during visual word recognition. The prime task effect refers to the elimination of the typically robust semantic priming effect by a nonsemantic prime task (e.g., subjects search the prime word for a letter). The purpose of this paper is to provide a tutorial review of the literature examining the prime task effect. Understanding the nature of this effect has implications for delineating how selective attention modulates evidence for semantic activation during word reading. These implications are outlined. Additionally, speculations for how these issues of selective attention relate to awareness are offered.     

Long-term semantic priming: A computational account and empirical evidence.

Semantic priming is traditionally viewed as an effect that rapidly decays. A new view of long-term word priming in attractor neural networks is proposed. The model predicts long-term semantic priming under certain conditions. That is, the task must engage semantic-level processing to a sufficient degree. The predictions were confirmed in computer simulations and in 3 experiments. Experiment 1 showed that when target words are each preceded by multiple semantically related primes, there is long-lag priming on a semantic decision task but not on a lexical-decision task. Experiment 2 replicated the long-term semantic priming effect for semantic decisions with only one prime per target. Experiment 3 demonstrated semantic priming with much longer word lists at lags of 0, 4, and 8 items. These are the first experiments to demonstrate a semantic priming effect spanning many intervening items and lasting much longer than a few seconds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What is learned about nontarget items in simple visual search?

Human sensitivity to correlational structure between nontargets and likelihood of target presence in a visual letter-search task were studied in two experiments. In each of these experiments, the performance of subjects for whom the nontarget information was altered in the final trial block was compared with the performance of subjects for whom the nontarget information did not change. When stimulus strings were presented individually on a computer screen and subjects were required to make a yes-no decision about target presence (Experiment 1), the change in nontarget structure resulted in increased reaction times for target-absent trials. When subjects searched simultaneously for three possible targets (Experiment 2), the change in nontarget structure produced increased error rates and increased reaction times for both target-absent and target-present trials. Correlations between the amount of predictive information in individual stimulus strings and reaction times also showed that both switching and nonswitching subjects were sensitive to the nontarget context. However, neither self-reports of strategy nor postexperiment choices between context-consistent and-inconsistent letter strings indicated any explicit knowledge of the predictive information in the nontarget stimuli. Subjects can thus acquire and benefit from, apparently without awareness, information about subtle correlational structure in nontarget elements in simple visual search.     

Adding new word associations to semantic memory: evidence for two interactive learning components

The addition of newly learned word associations to semantic memory was investigated in three experiments. In these experiments word pairs were repeatedly presented as prime-target pairs in a lexical decision task. Performance on repeated pairs (both pre-experimentally associated and initially unrelated pairs) was compared to that on neutral pairs. In Experiments 1 and 2, effects of prior study (episodic priming) were observed but since this episodic priming effect was equal for both conditions it could not be concluded that the new associations has been added to semantic memory. In Experiment 3 some evidence was found that the newly learned word associations had been added to semantic memory. This occurred only after presenting the word pairs for several trials in paired-associate learning. The results are interpreted as supporting a model that distinguishes two memory components that mediate the effects of new learning, an episodic and a semantic one.     

Why do semantic priming effects increase in old age? A meta-analysis.

Reports a meta-analysis comparing the size of semantic priming effects on young and older adults' lexical decision and pronunciation latency. The analysis included 15 studies with 49 conditions varying the semantic relatedness of a prime stimulus (single word or whole sentence) and a target word. An effect-size analysis on the difference between young and older adults' semantic priming effect (unrelated minus related latency) indicated that semantic priming effects are reliably larger for older than for young adults. There was no evidence for nonhomogeneity in this age difference across the different conditions. The relationship between young and older adults' semantic priming effects was described by a function with a positive intercept and a slope of 1.0. This pattern of findings favors aging models postulating process-specific slowing rather than general cognitive slowing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word-based grouping affects the prime-task effect on semantic priming.

Semantic priming between words is reduced or eliminated if a low-level task such as letter search is performed on the prime word (the prime task effect), a finding used to question the automaticity of semantic processing of words. This idea is critically examined in 3 experiments with a new design that allows the search target to occur both inside and outside the prime word. The new design produces the prime task effect (Experiment 1) but shows semantic negative priming when the target letter occurs outside the prime word (Experiments 2 and 3). It is proposed that semantic activation and priming are dissociable and that inhibition and word-based grouping are responsible for reduction of semantic priming in the prime task effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unconscious Primes Activate Motor Codes Through Semantics.

Today, it is generally accepted that unconscious stimuli can activate a response code, which leads to a response congruency effect (RCE) on a subsequent target. However, it is not yet clear whether this is due to the semantic processing of the primes or to the formation of direct stimulus-response (S-R) associations bypassing the semantic system. Recently, it was shown that even novel primes, for which no direct S-R links exist, can also evoke an RCE that is in line with the activation of response codes through semantics. In these experiments, the authors examined 3 alternatives for this RCE from novel primes and report a novel effect in unconscious priming. First, the authors show that this effect is not limited to a small set of numerical stimuli but also extends to letter stimuli (Experiments 1-3). Second, the authors show that the RCE is not a side effect of the prime-target distance effect, as has been reported before (Experiments 1-2). Third, the authors found that, for RCE to occur, overlap at the motor level but not at the semantic level was crucial (Experiments 2-3). Finally, in addition, the results showed a category match priming effect independent of RCE. This last result is evidence that novel unconscious primes activate their semantic category prior to the target and might be considered a good marker for semantic processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic priming in major depressive state

We studied semantic priming in 20 major depressive subjects. The methodology used was a visual lexical decision task. Semantic priming is the facilitation of target word recognition (shortening of response time) by the prior presentation of a semantically related context (a prime word). It relies on semantic processing of words and context, facilitating early cognitive stages of response. Varying the temporal interval between prime and target words onset allows us to distinguish between two priming mechanisms, relying on more automatic (test 1) or more controlled (i.e. attention dependent) (test 2) information processing. We observe a significant retardation for words and pseudo-words in depressives (in relation to controls) in both tests. In spite of a general retardation and increase of response times in depressives, semantic priming is evident in both groups and both tests, and does not differ significantly between depressive and control groups in either automatic or controlled conditions. Theses results confirm that semantic processing is not impaired in depression, and are discussed with regard to the hypothesis of an effortful processing impairment in depression, and to depressive retardation.     

Facilitation of word recognition by semantic priming in schizophrenia.

Schizophrenic (n?=?21), bipolar (n?=?18), and normal control subjects (n?=?21) were compared on a word recognition measure of semantic priming. The task involved the presentation of related, neutral, and unrelated word pairs; the second word (target word) in each pair was presented in a degraded form. Facilitation was defined as the accuracy of target word recognition for the related word pairs minus accuracy for the neutral word pairs. Titration, achieved by manipulating the degradation of the target word, was used to maintain each subject's overall accuracy for related and neutral items at approximately 50%. This procedure minimized the artifactual effects of overall accuracy on the difference score. Schizophrenics exceeded both normal control subjects and bipolar subjects on facilitation. Bipolar subjects did not differ from control subjects. The results support Maher's hypothesis that semantic priming effects are heightened in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Levels of representation in visual word recognition: a dissociation between morphological and semantic processing

A robust semantic priming effect typically occurs in visual word recognition if the prime is read before a response to the target. However, this effect is dramatically reduced if a letter search is performed on the prime prior to responding to the target. Three lexical decision experiments document the new observation that morphological priming is preserved following letter search on the prime. This dissociation between morphological and semantic priming following letter search can be understood in the context of an interactive activation framework. In addition, the implications of these results for connectionist and compound cue accounts of word recognition, as well as the issue of automaticity in word recognition, are discussed.