Multiple-feature discrimination faster than single-feature discrimination within the same object?

In the present study, we investigated whether judging the presence of multiple features within an object would be superior to judging the presence of only one feature. Feature discriminability and the number of features to discriminate within an object were varied. Specific features were judged as present or absent. Results showed that judging the presence of two or three features was faster than judging the presence of the less discriminable of these two or three features alone (multiple-feature benefits). These findings suggest that relevant features within an object activate (prime) a decision or response in a parallel, asynchronous fashion based on discriminability (Miller, 1982a). The ability of a response priming model, a response mapping model, and a template model to account for multiple-feature benefits is discussed.     

Attentional demands of visual word recognition.

Becker's (1976, 1979, 1980, 1985; Becker & Killion, 1977; Eisenberg & Becker, 1982) verification model was used as a framework to investigate the attentional demands of word recognition. In two experiments, a lexical decision task and an auditory probe task were performed in single- and dual-task conditions. Responses to probes were divided into detection and movement measures that indexed the demands of recognition and response output, respectively. In Experiment 1, single- to dual-task decrements in probe detection performance were larger during low-frequency as compared with high-frequency trials. This finding indicates that the attentional demands of word recognition vary with word frequency. These findings were replicated in Experiment 2, which was designed to separate a response compatibility and a capacity interpretation of the results. The findings are interpreted within Becker's verification model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional requirements of automatic and controlled processing.

The attentional demands of automatic and controlled processing were investigated in a dual task paradigm. Ss performed consistent and varied mapping versions of an S. Sternberg (see record 1966-10810-001) memory search task, both separately and together with a recognition running-memory task. In different conditions, Ss were instructed to maximize their performance on either the Sternberg or running memory tasks or to emphasize the tasks equally. Processing priority and memory load had large effects on performance when the variably mapped version of the Sternberg task was paired with the running memory task. Performance decrements in these conditions were accompanied by trade-offs in the amplitude of the P300 component of the event-related brain potential, presumably reflecting the distribution of attention between the tasks. Performance in the consistently mapped version of the Sternberg task was relatively unaffected by memory load or dual task demands. Large P300s, which were insensitive to manipulations of memory load and priority, were elicited in the consistently mapped conditions. These P300s appear to reflect the obligatory allocation of attention to task-relevant events during automatic processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A test of the frontal lobe functioning hypothesis of age deficits in production priming.

Older adults have been hypothesized to show reduced priming relative to younger adults on implicit memory tests that require production of a response because these tasks place high demands on attentional processes associated with frontal lobe function, which are often reduced with age (see D. A. Fleischman & J. D. E. Gabrieli, 1998). The current study directly tested this frontal lobe hypothesis of age effects in production priming. Younger adults and older adults who differed in their attentional abilities as measured by a battery of neuropsychological tests were given two production priming tasks, word stem completion and category production, followed by explicit free recall tests. Results showed that explicit memory performance was reduced by age and older adults' frontal functioning. Age and frontal functioning influenced category production priming but not word stem completion priming. Results failed to support the frontal account of age reductions in production priming. Instead, results implicate the influence of other processes often involved in production priming tasks, such as explicit memory strategies and response competition, as critical for understanding age effects in implicit memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of stimulus modality and task condition on blink startle modification and on electrodermal responses

Participants in Experiments 1 and 2 performed a discrimination and counting task to assess the effect of lead stimulus modality on attentional modification of the acoustic startle reflex. Modality of the discrimination stimuli was changed across subjects. Electrodermal responses were larger during task-relevant stimuli than during task-irrelevant stimuli in all conditions. Larger blink magnitude facilitation was found during auditory and visual task-relevant stimuli, but not for tactile stimuli. Experiment 3 used acoustic, visual, and tactile conditioned stimuli (CSs) in differential conditioning with an aversive unconditioned stimulus (US). Startle magnitude facilitation and electrodermal responses were larger during a CS that preceded the US than during a CS that was presented alone regardless of lead stimulus modality. Although not unequivocal, the present data pose problems for attentional accounts of blink modification that emphasize the importance of lead stimulus modality.     

The role of attention in a spatial memory task in Alzheimer disease patients

Memory and attention are interrelated cognitive processes that most likely influence the functioning of each other, yet they are often difficult to distinguish in psychological experiments. Young, aged adults, and patients with Alzheimer disease (AD) were tested on a delay response task measuring spatial memory that also placed high demands on attentional resources. Aged adults performed as well as young, suggesting that neither attentional nor memory abilities were exceeded in either group. However, AD subjects were severely impaired on this task. Two further experiments with AD patients examined the relative contribution of attentional and memory deficits in the performance of this population. Both memory and attentional impairments were found; however, errors due to memory factors were more closely related to severity of disease as measured on the Folstein Mini-Mental State Examination than were errors of attentional origin. These studies demonstrate the necessity of accounting for attentional components in studies examining memory, especially in patients with AD.     

Arousal contributions to affective priming: Electrophysiological correlates.

Current models of affective processing postulate that not only valence but also the arousal dimension characterizes the emotional experience. However, up-to-date research on affective priming has mainly focused on the contributions of valence congruency to priming. In this study, the authors explored the possible influence of arousal in priming processes. For this purpose, event-related potentials and reaction times were measured in response to high- and low-arousing positive targets that were either congruent or incongruent in arousal with a prime word. Priming arousal did not influence reaction times. By contrast, the processing of high-arousing targets was facilitated by a previous exposure to a congruent prime, as reflected by the reduction in the amplitude of a late positive component around 500 ms that has been thought to reflect attentional and memory processes. These results diverge from the findings of previous studies that primed valence and suggest a differential contribution of arousal and valence to affective priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The organization of multidimensional selection on the basis of color and shape: an event-related brain potential study

In this paper, we examine whether color and shape, tied to a single object in space, (1) are identified and selected in series or in parallel, (2) are identified and selected in a dependent, self-terminating manner or in an independent and exhaustive manner, and (3) are conjoined by a feature integration process before or only after an initial stage of separate attribute analyses has finished. We measured response time and the selection negativity (SN) derived from event-related brain potentials when participants responded to a unique conjunction of color and shape in a go/no-go target detection task. The discriminability of the color and the shape of the conjunction was manipulated in three conditions. When color and shape were easy to discriminate, the SNs to color and shape started at the same time. When one attribute was less discriminable the SN to that attribute started later, but not the SN to the complementary attribute. This suggests that color and shape are identified and selected in parallel. In all three discriminability conditions, the SNs to color and shape were initially independent but later interacted. This suggests that color and shape are initially selected independently and exhaustively, after which their conjunction is analyzed. The SN to local shape features started later than that to the conjunction of color and global shape features, which suggests that feature integration can start before the analyses of the separate attributes have finished.     

A two-stage model for multiple target detection in rapid serial visual presentation.

When 2 targets are presented among distractors in rapid serial visual presentation, correct identification of the 1st target results in a deficit for a 2nd target appearing within 200–500 ms. This attentional blink (AB; J. E. Raymond, K. L. Shapiro, & K. M. Arnell, 1992) was examined for categorically defined targets (letters among nonletters) in 7 experiments. AB was obtained for the 2nd letter target among digit distractors (Experiment 1) and also for a 3rd target (Experiment 2). Results of Experiments 3–5 confirmed that AB is triggered by local interference from immediate posttarget stimulation (Raymond et al., 1992) and showed that AB is modulated by the discriminability between the 1st target and the immediately following distractor. Experiments 5–7 further examined the effects of both local interference and global discriminability. A 2-stage model is proposed to account for the AB results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive sequence knowledge: What is learned?

In 4 experiments, participants performed running-arithmetic tasks. These tasks involved a sequential ordering of individual operations and a structure of subgoals that defined how calculations fit together in purpose. Consistent transitions between adjacent steps facilitated performance only when subgoal structures were relatively simple. When subgoal structures were more complex, consistent mapping of operations to serial locations produced a slight benefit. Consistently of subgoal structure produced a substantial benefit in both speed and accuracy, and some knowledge of subgoal structure integrated with knowledge of the sequence of operations. Apparently, a task's subgoal structure imposes demands that either facilitate or obscure benefits of sequence consistencies. The benefits are attributed to increase deficiency in using working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transsaccadic perception of saccade target and flanker objects.

To account for location-dependent and location-independent preview benefits in transsaccadic object perception, J. M. Henderson (1994) and J. M. Henderson and M. D. Anes (1994) proposed a dual-route model in which both episodic object representations and long-term memory representations store information across a saccade. Four experiments are reported in which the dual-route model was assessed. Preview benefits for saccade target objects were found to be location independent, whereas preview benefits for flanker objects were location dependent. These results support a single-route, 2-stage model of transsaccadic object perception. First, preattentive object files are set up to parse a set of attentional and/or saccade targets from peripheral vision, causing location-dependent preview benefits. Second, 1 object is attentionally selected for further processing, activating long-term memory representations and resulting in location-independent preview benefits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of task demands on implicit memory for object-location associations.

Examined the effect of task demands and the nature of the object probed on implicit and explicit memories for object location associations, in 5 experiments. 111 undergraduates probed objects (letters or symbols), 1 at a time, in 1 of 9 locations in a rectangle. They located or named the object. Each object was probed in the same location across 10 trial blocks, and then all the objects changed locations. Decrease or increase in naming times across trials was noted to find out the presence of priming for associations. Results show that implicit and explicit memory were affected differently by task demands. Priming could be obtained when the task engaged, but did not overtax, attentional capacity. Explicit memory performance was best when the task did not require much attentional capacity. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The comparison of visual working memory representations with perceptual inputs.

The human visual system can notice differences between memories of previous visual inputs and perceptions of new visual inputs, but the comparison process that detects these differences has not been well characterized. In this study, the authors tested the hypothesis that differences between the memory of a stimulus array and the perception of a new array are detected in a manner that is analogous to the detection of simple features in visual search tasks. That is, just as the presence of a task-relevant feature in visual search can be detected in parallel, triggering a rapid shift of attention to the object containing the feature, the presence of a memory–percept difference along a task-relevant dimension can be detected in parallel, triggering a rapid shift of attention to the changed object. Supporting evidence was obtained in a series of experiments in which manual reaction times, saccadic reaction times, and event-related potential latencies were examined. However, these experiments also showed that a slow, limited-capacity process must occur before the observer can make a manual change detection response. (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.     

How Much Attention Does an Event File Need?

Attentional requirements for the spontaneous integration of stimulus and response features were analyzed. In line with previous findings, carrying out a prepared response to the onset of a stimulus created bindings between the response and the features of that stimulus, thereby impairing subsequent performance on mismatching stimulus-response combinations. Findings demonstrate that a stimulus gets bound to a response even if its presence is neither necessary nor useful for the task at hand, it follows rather than precedes the response in time, it competes with a task-relevant stimulus, and if the response is suppressed-but only if the stimulus appears close to the response's eventual execution or abandonment. A multiple-integration model is suggested that assumes that the integration of stimulus features in perception and of response features in action planning are local processes that are independent of stimulus-response integration, which presumably is triggered by the success of the perception-action episode. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Disentangling the adult attention-deficit hyperactivity disorder endophenotype: Parametric measurement of attention.

Attention deficit hyperactivity disorder (ADHD) persists frequently into adulthood. The decomposition of endophenotypes by means of experimental neuro-cognitive assessment has the potential to improve diagnostic assessment, evaluation of treatment response, and disentanglement of genetic and environmental influences. We assessed four parameters of attentional capacity and selectivity derived from simple psychophysical tasks (verbal report of briefly presented letter displays) and based on a “theory of visual attention.” These parameters are mathematically independent, quantitative measures, and previous studies have shown that they are highly sensitive for subtle attention deficits. Potential reductions of attentional capacity, that is, of perceptual processing speed and working memory storage capacity, were assessed with a whole report paradigm. Furthermore, possible pathologies of attentional selectivity, that is, selection of task-relevant information and bias in the spatial distribution of attention, were measured with a partial report paradigm. A group of 30 unmedicated adult ADHD patients and a group of 30 demographically matched healthy controls were tested. ADHD patients showed significant reductions of working memory storage capacity of a moderate to large effect size. Perceptual processing speed, task-based, and spatial selection were unaffected. The results imply a working memory deficit as an important source of behavioral impairments. The theory of visual attention parameter working memory storage capacity might constitute a quantifiable and testable endophenotype of ADHD. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Dissociations in Hippocampal and Frontal Contributions to Episodic Memory Performance.

The hippocampus and frontal lobes both contribute to episodic memory performance. In the present study, the authors evaluated the relative contributions of hippocampus, frontal lobes, anterior temporal cortex, and posterior cortex to memory performance in neurodegenerative patients and normal older controls. Subjects (n = 42) were studied with structural MRI and a memory paradigm that measured delayed recall, semantic clustering during recall, recognition discriminability, and recognition response bias. Data were analyzed with multiple regression. Consistent with the authors' hypotheses, hippocampal volumes were the best predictor of delayed recall and recognition discriminability, whereas frontal volumes were the best predictor of semantic clustering and response bias. Smaller frontal volumes were associated with less semantic clustering during recall and a more liberal response bias. Results indicate that hippocampal and frontal contributions to episodic memory can be dissociated, with the hippocampus more important for memory accuracy, and frontal structures more important for strategic processing and decision making. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of attention in feature detection and conjunction discrimination: an electrophysiological analysis

An electrophysiological probe technique was used to ascertain whether the same attentional mechanisms are employed for both the detection of simple visual features and the discrimination of conjunctions of features. Visual search arrays containing 14 grey items and 2 colored items were presented; one color was designated relevant for each trial block. Subjects were required to report the presence or absence of the relevant color (feature detection condition) or the shape of the relevantly-colored item (conjunction discrimination condition). Shortly after the onset of the search array, a task-irrelevant probe stimulus was flashed at the location of the relevant or irrelevant color and the event-related potential (ERP) produced by this stimulus was used to assess sensory processing at the probed location. Probes presented at the location of the relevant color were found to elicit enhanced ERP components and probes presented on the opposite side of the display from the relevant color elicited suppressed components. These effects were observed in both the detection and discrimination conditions, indicating that spatially restricted attentional processes are used for both the detection of simple features and the discrimination of conjunctions. However, one ERP component (the PI wave) exhibited these effects in the discrimination condition but not in the detection condition, indicating that conjunction discrimination utilizes additional attentional processes beyond those required for feature detection.     

Encoding processes and attentional inhibition in directed forgetting.

Lexical decisions were used to evaluate whether forget (F)-cued prime words affect subsequent encoding of target words relative to remember (R)-cued prime words. In 3 experiments, R-cued primes were better recalled than F-cued primes. Targets that followed F-cued primes were responded to faster than targets that followed R-cued primes in same-case and different-case identity priming. Semantic printing occurred for targets that followed both types of memory-cued primes. However, response times were longer for both related and unrelated targets following R-cued primes relative to F-cued primes. These results indicate that R and F items are processed to similar levels of representation and inhibitory mechanisms do not attenuate encoding of F items. However, there is slower access to working memory for information that follows R-cued items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)