Lexical access without attention? Explorations using dichotic priming.

The authors used lexical decision in a dichotic listening situation and measured identity priming across channels to explore whether unattended stimuli can be processed lexically. In 6 experiments, temporal synchronization of prime and target words was manipulated, and acoustic saliency of the unattended prime was varied by embedding it in a carrier sentence or in babble speech. When the prime was acoustically salient, a cross-channel priming effect emerged, and participants were aware of the prime. When the prime was less salient, no identity priming was found, and participants failed to notice the prime. Saliency was manipulated in ways that did not degrade the prime. Results are inconsistent with models of late filtering, which predict equal priming irrespective of prime saliency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Children's event-related potentials of auditory selective attention vary with their socioeconomic status.

Past research suggests a link between socioeconomic status (SES) and brain processes in children, but direct evidence from neuroimaging is scarce. The authors investigated the relationships among SES, performance, and the neural correlates of auditory selective attention, by comparing event-related potentials (ERPs) in lower- and higher-SES preadolescent children during a task in which they attended to two types of pure tones but ignored two other types. Our hypothesis was that, at comparable performance levels, higher-SES children ignore distracters (the unattended, irrelevant tones) while lower-SES children attend equally to distracters and to targets (the attended, relevant tones). The authors found that ERP waveform differences between attended and unattended tones (Nd, difference negativity) were significant in the higher-SES but not in the lower-SES group. However, the groups did not differ in reaction times or accuracy. Electroencephalographic power analysis revealed a differential pattern of theta activity concomitant with irrelevant tones for the two groups, indicating that although they performed similarly the children from these groups recruited different neural processes. Lower-SES children, the authors suggest, deployed supplementary resources to also attend to irrelevant information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship between priming and recognition in deterministic and probabilistic sequence learning.

Exposure to a repeating sequence of target stimuli in a speeded localization task can support both priming of sequence-consistent responses and recognition of sequence components. In 3 experiments with both deterministic and probabilistic sequences, the authors used a novel procedure in which measures of priming and recognition were taken concurrently and asked whether these measures can be dissociated. In all of these experiments, both measures were above chance at the group level and no evidence of dissociation was found. Item-level analyses of the data in Experiment 3 did reveal dissociations in that (a) recognition judgments were affected by response speed independently of old-new status and (b) items that were not discriminated in recognition nonetheless showed priming. However, the authors show that these data, together with the group-level results, are compatible with a formal model in which priming and recognition are based on a single common memory variable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective reading: Attention to the "unattended" lines.

Previous research on selective reading indicates that upon direct questioning Ss are usually unable to recall words that appear in irrelevant lines. In 3 experiments with male 6th graders (n = 24) and college freshmen (n = 31), a procedure was developed to examine the influence of the unattended lines on memory for the words in attended lines in selective reading. In each study, q of the Ss were given a set of selective reading passages to be read aloud. In the irrelevant lines of each passage were wrong answers to the questions which followed that story. The remainder of the Ss in each experiment read control passages without irrelevant lines. Results show that although Ss in the selective reading condition could not recall the words in the irrelevant lines, their answers to the questions following each passage were influenced by that "unattended" material. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Children do show negative priming: Further evidence for early development of an intact selective control mechanism.

Reactions to stimuli that were shortly before presented as distractors are usually slowed down; this phenomenon is known as negative priming. Negative priming is an accepted index for tapping into selective control mechanisms. Although this effect is well established for adults, it has been claimed that children do not show negative priming. Recently, however, V. E. Pritchard and E. Neumann (see record 2004-11032-006) challenged this view and concluded that selective control mechanisms are already fully developed in young children. The authors of the present study analyzed differences between older studies, in which no negative priming had been observed, and the Pritchard and Neumann (2004) study. In sum, the present study yielded further evidence for an intact selective control mechanism in young children. The authors also linked this empirical finding to the broader literature on negative priming by a direct comparison with an adult sample. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Facilitation of unattended semantic information in Alzheimer's disease: Evidence from a selective attention task.

Processing of unattended semantic information was examined in 13 patients with Alzheimer's disease (AD) and 23 normal controls (NC) using a selective attention, priming task. Two vertically aligned pictures of objects served as primes, and object names were targets. Participants were instructed to attend to only 1 picture, defined by color, in the prime display. NC participants showed facilitation only for target items that were the name of the attended prime picture, but AD patients showed facilitation from the attended and unattended prime pictures. Two accounts of these data posit a deficit in the initiation of the selection component of selective attentional processing in AD. On the basis of spotlight theories, a 3rd account posits a deficit in AD patients' ability to adjust the scope of the selection "beam." Last, facilitation of attended and unattended information may be due to crosstalk between accurately selected and unselected information. Implications of the activation of irrelevant information to language function in AD are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Global and local precedence: Selective attention in form and motion perception.

Five experiments traced the causes of the discrepancy in research that showed both local and global precedence in selective attention tasks. The effects of the relative discriminabilities of the local and global levels of the stimuli and the differences between Stroop-type interference (attributable to incongruity on the irrelevant dimension) and Garner-type interference (attributable to variability on the irrelevant dimension) were explored. The experiments also examined whether the precedence effects previously examined in form perception generalize to motion perception. 45 Ss, most of whom were college students, participated. Ss viewed stimuli on an oscilloscope under 9 conditions. Results show that (a) some cases of global precedence were due solely to the greater perceptual discriminability of the global level; (b) instances of both local and global precedence could be demonstrated for certain types of stimuli, even when the discriminabilities of their local and global levels had been equated; and (c) the Stroop and Garner measures of selective attention were not equivalent but instead measured different types of interference. It is concluded that cases of both local and global precedence have been amply documented but that no general theory can account for why or when these effects will appear until a better understanding is gained of both the nature of part–whole relationships and the perceptual processes that are tapped by different measures of selective attention. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Persistence of negative priming: Steady state or decay?

Responses to recently ignored stimuli may be slower and less accurate than responses to new stimuli. W. T. Neill and R. L. Westberry (1987) found that such negative priming effects dissipated within a 2-sec interval between response and the next stimulus, the response–stimulus interval (RSI). However, experiments by S. P. Tipper et al, (1991) found negative priming persisted unchanged over RSIs from 1,350 to 6,600 msec. The current experiments used a letter-matching procedure in which target letters were flanked by irrelevant letters. Negative priming was manifested by longer reaction times (RTs) and more errors to letters that had appeared as flankers in the preceding trial. RSI was varied from 500 to 8,000 msec. Negative priming diminished over the RSI, particularly within the 1st sec. This effect did not depend on the presence or absence of temporal uncertainty or on Ss' awareness of intertrial relations. An episode retrieval theory to account for negative priming phenomena is proposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affective priming with subliminally presented pictures.

Affective priming studies have demonstrated that subliminally presented prime words can exert an influence on responses towards positive or negative target stimuli. In the present series of experiments, it was investigated whether these findings can be extended to pictorial stimuli. Ideographically selected positive, neutral, and negative picture primes that were sandwich-masked immediately preceded positive or negative target pictures (Experiment 1) or words (Experiments 2 & 3). Evaluative categorization responses to these target stimuli were significantly influenced by the valence of the prime. First, it was demonstrated that high anxious participants were selectively slowed when the subliminally presented prime was negative (Experiments 1 & 2). Second, the affective congruence between primes and targets also exerted an influence on the responses, but in a direction that is opposite to what is typically observed in affective priming research. These reverse priming effects are situated within a series of recent similar findings, and implications for theories of affective priming are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Role of Fear-Relevant Stimuli in Visual Search: A Comparison of Phylogenetic and Ontogenetic Stimuli.

It has been argued that phylogenetic fear-relevant stimuli elicit preattentive capture of attention. To distinguish between fear relevance and time of appearance in evolutionary history, the authors compare phylogenetic and ontogenetic fear-relevant and fear-irrelevant stimuli in a visual search task. The authors found no evidence for a special role of phylogenetic fear-relevant stimuli; it seems that fear relevance in general is more important than is the evolutionary age. The pattern of results indicates that attention toward threatening stimuli is mainly affected by a late component that prolongs the disengagement of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identity negative priming in older adults and individuals with dementia of the Alzheimer type.

This study addressed the question of whether dementia of the Alzheimer type (DAT) produces a breakdown in aspects of the inhibitory component underlying selective attention. Two measures of identity negative priming and 2 measures of distractor interference were obtained. In Experiment 1, participants were presented with overlapping picture stimuli, and in Experiment 2, participants were presented with overlapping written word stimuli. The results of both experiments produced reliable and similar size negative priming in young and old adults, but there was no evidence of negative priming in the individuals with DAT. In contrast, the naming latencies of all 3 groups showed a reliable and similar size distractor interference effect. These results suggest that although the inhibitory component underlying selective attention is impaired in individuals with DAT, the ability to differentiate a target from a distractor may be preserved under certain task conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

No negative semantic priming from unconscious flanker words in sight.

In replicating 1 of the within-language conditions of E. Fox's (1996) Experiment 1, the authors confirmed that unattended words presented 2.4° above and below fixation are mostly unavailable to awareness. However, no negative semantic priming was observed in a lexical decision on a probe letter string appearing about 1 s later, which does not replicate Fox's finding. These results are compatible with the hypothesis underlying the present study, according to which positive semantic priming, if any, rather than negative semantic priming is expected in Fox's situation. The reason is that unavailability to awareness of the parafoveal words is not achieved by means of an act of selective inhibition combined with attentional diversion through masking but is achieved simply by means of perceptual degradation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition and aging: Similarities between younger and older adults as revealed by the processing of unattended auditory information.

The ability to selectively attend to an auditory stimulus appears to decline with age and may result from losses in the ability to inhibit the processing of irrelevant stimuli (i.e., the inhibitory deficit hypothesis; L. Hasher & R. T. Zacks, 1988). It is also possible that declines in the ability to selectively attend are a result of age-related hearing losses. Three experiments examined whether older and younger adults differed in their ability to inhibit the processing of distracting stimuli when the listening situation was adjusted to correct for individual differences in hearing. In all 3 experiments, younger and older adults were equally affected by irrelevant stimuli, unattended stimuli, or both. The implications for auditory attention research and for possible differences between auditory and visual processing are discussed. (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)     

Inhibition of Return and Repetition Priming Effects in Localization and Discrimination Tasks.

Inhibition of return (IOR) refers to slower responding to a stimulus that is presented at the same, rather than a different location as a preceding, spatially nonpredictive, stimulus. Repetition priming refers to speeded responding to a stimulus that duplicates the visual characteristics of a stimulus that precedes it. IOR and repetition priming effects interact in nonspatial discrimination tasks but not in localization tasks; three experiments examined whether this is due to processing differences or due to response differences between tasks. Two stimuli, S1 and S2, occurred on each trial. In Experiment 1, S1 and S2 were both peripheral arrows; in Experiment 2, S1 was a central arrow and S2 was a peripheral nondirectional rectangle; in Experiment 3, S1 was a peripheral nondirectional rectangle and S2 was a peripheral arrow. S1 never required a response; S2 required a localization or a discrimination response. Despite evidence that form information was likely extracted from the arrow stimuli, the localization task revealed no repetition priming: IOR occurred regardless of shared visual identity of the S1 and S2 arrows. The discrimination task revealed IOR only when the visual identity changed from S1 to S2; otherwise, facilitation occurred. These results suggest that IOR is masked by repetition priming only when the response depends on the explicit processing of form information; repetition priming does not occur when such information is extracted automatically but is task (and response) irrelevant. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic processing precedes affect retrieval: The neurological case for cognitive primacy in visual processing.

According to the affective primacy hypothesis, visual stimuli can be evaluated prior to and independent of object identification and semantic analysis (Zajonc, 1980, 2000). Our review concludes that the affective primacy hypothesis is, from the available evidence, not likely correct. Although people can react to objects that they cannot consciously identify, such affective reactions are dependent upon prior semantic analysis within the visual cortex. The authors propose that the features of objects must first be integrated, and then the objects themselves must be categorized and identified, all prior to affective analysis. Additionally, the authors offer a preliminary neurological analysis of the mere exposure and affective priming effects that is consistent with the claim that semantic analysis is needed to elicit these effects. In sum, the authors conclude that the brain must know what something is in order to know whether it is good or bad. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acquisition of superexcitatory properties by an irrelevant background stimulus.

Six appetitive conditioning experiments with rats demonstrated that an irrelevant X accompanying a negative patterning discrimination (XA+, XB+, XAB-) acquires extraordinarily high levels of conditioned excitation. Responding to X was similar to that evoked by 2 excitors in combination (Experiment 1) and was greater than responding to a separately reinforced Y (Experiments 2-5). Superexcitatory properties were not acquired by X in the nonpatterning discriminations of Experiments 2-4. Experiment 5 found that A and B, if anything, were weakly excitatory. Making them more strongly excitatory after conditioning did not interfere with retention of the original discrimination (Experiment 6). Results support a counterintuitive prediction of associative theories that, under carefully arranged conditions, irrelevant stimuli may acquire superexcitatory properties. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unattended words need to be primed to be recognized

The categorical relation between a target word and a flanking, to-be-ignored, nontarget word can influence target response. Although usually taken as evidence of a full and automatic analysis of stimuli whether or not they have been attended, this flanker effect may only point to the failure of focused attention when nontarget stimuli have been primed and made task-relevant. The present study examined the role of priming in the flanker task. In one condition, schematic and semantic priming of nontargets was potentiated by having subjects categorize the target as an instance of a living or nonliving thing. In a second condition, priming was minimized by requiring only a shallow analysis of the target for a response; subjects searched the target for the presence of the letter R. A flanker effect was found only in the categorization condition, and then only when the target was the name of an animal. There was no evidence that unattended nontargets had been fully and automatically encoded to a semantic level.     

Negative Priming Effects in Children Engaged in Nonspatial Tasks: Evidence for Early Development of an Intact Inhibitory Mechanism.

Three experiments are reported that examined conceptual negative priming effects in children 5 to 12 years of age. Experiment 1 used a negative priming variant of a flanker task requiring the naming of a central color blob flanked by irrelevant distractors. Experiment 2 used a negative priming variant of the Stroop color-word task. Experiment 3 used a same-different matching task with novel 3-D shapes. Results revealed significant and equivalent magnitudes of negative priming across the tested age groups for all 3 tasks. It is concluded that the inhibitory mechanism underlying conceptual (i.e., identity or semantic) negative priming in visual selective attention tasks is intact in young children. Because the findings and conclusions diverge from the developmental literature on negative priming, the authors attempt to reconcile the contradictions by pinning down the reasons for the discrepancies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)