Spatial attention and implicit sequence learning: Evidence for independent learning of spatial and nonspatial sequences.

This research investigated whether regular spatial orienting sequences can be learned implicitly and independently of response requirements. In a new version of a serial response task introduced by M. J. Nissen and P. Bullemer (1987) participants had to discriminate between objects that could occur at different locations. Independent sequences determined the succession of locations and objects. Even participants who were not aware of any regularities exhibited evidence for learning of both sequences (Experiment 1). Experiment 2 showed that the joint learning of spatial and object sequences was as efficient as learning of single sequences and that it even occurred when learning required memory for past sequence elements and attention was blocked through a secondary tone-counting task. Results are consistent with the idea that independent systems may exist for the implicit acquisition of spatial and nonspatial regularities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parallel response selection disrupts sequence learning under dual-task conditions.

Some studies suggest that dual-task processing impairs sequence learning; others suggest it does not. The reason for this discrepancy remains obscure. It may have to do with the dual-task procedure often used. Many dual-task sequence learning studies pair the serial reaction time (SRT) task with a tone-counting secondary task. The tone-counting task, however, is not ideal for studying the cognitive processes involved in sequence learning. The present experiments sought to identify the nature of the interference responsible for disrupting sequence learning in dual-task situations using more tractable dual-task procedures. Experiments 1 and 2 showed that parallel-interfering central processing disrupts sequence learning. Experiment 3 used a novel combination of the SRT task as the secondary task in a psychological refractory period procedure. It showed that SRT task performance can be disrupted without disrupting sequence learning when that disruption involves a response-selection bottleneck rather than parallel response selection. Together, these results suggest that it is the overlap of central processes involved in successfully performing the 2 tasks concurrently that leads to learning deficits in dual-task sequence learning. (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)     

Hypnotic underestimation of time: The busy beaver hypothesis.

Two experiments tested the hypothesis that the hypnotic underestimation of time is mediated by attentional processing. In Exp 1, variations in the demands placed on attentional resources produced substantial differences in the subjective estimates of identical length intervals occurring within a hypnotic context. ln Exp 2, attentional manipulation was assessed in both hypnotic and waking contexts. Time judgments were again found to vary with attentional demands but not with hypnotic context. The results are consistent with a busy beaver hypothesis, which holds that hypnotic, as well as nonhypnotic, time estimates are a by-product of the attentional processing demands of the task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequence learning and selection difficulty.

The authors studied the role of attention as a selection mechanism in implicit learning by examining the effect on primary sequence learning of performing a demanding target-selection task. Participants were trained on probabilistic sequences in a novel version of the serial reaction time (SRT) task, with dual- and triple-stimulus participants having to ignore irrelevant items in the SRT display. Despite large performance decrements under dual- and triple-stimulus configurations, testing under single-stimulus conditions revealed no impairment to sequence learning. These findings suggest that implicit sequence learning is resistant to disruption of the selection process. Results are discussed in terms of a componential model of attention and in relation to the implicit-explicit distinction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit Motor Learning in Parkinson's Disease.

Objective: This study examined whether disruption of performance is moderated in Parkinson's disease (PD) patients who acquire their motor behaviors in an implicit manner. Method: Twenty-seven patients with PD learned a hammering task in errorless (implicit) or errorful (explicit) conditions and were tested for robustness of motor performance under a secondary task load, which required them to continuously count backward as they performed the hammering task. Results: Patients in the errorless (implicit) motor learning condition exhibited robustness to secondary task loading, whereas patients in the errorful (explicit) motor learning condition did not. Conclusions: Implicit motor learning techniques should be considered by PD rehabilitation specialists in cases in which existing disruption to movements is exacerbated by conscious control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic contextual cuing and visual attention.

Since M. M. Chun and Y. Jiang's (1998) original study, a large body of research based on the contextual cuing paradigm has shown that the visuocognitive system is capable of capturing certain regularities in the environment in an implicit way. The present study investigated whether regularities based on the semantic category membership of the context can be learned implicitly and whether that learning depends on attention. The contextual cuing paradigm was used with lexical displays in which the semantic category of the contextual words either did or did not predict the target location. Experiments 1 and 2 revealed that implicit contextual cuing effects can be extended to semantic category regularities. Experiments 3 and 4 indicated an implicit contextual cuing effect when the predictive context appeared in an attended color but not when the predictive context appeared in an ignored color. However, when the previously ignored context suddenly became attended, it immediately facilitated performance. In contrast, when the previously attended context suddenly became ignored, no benefit was observed. Results suggest that the expression of implicit semantic knowledge depends on attention but that latent learning can nevertheless take place outside the attentional field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Choking under pressure: Multiple routes to skill failure.

Poor performance in pressure-filled situations, or “choking under pressure,” has largely been explained by two different classes of theories. Distraction theories propose that choking occurs because attention needed to perform the task at hand is coopted by task-irrelevant thoughts and worries. Explicit monitoring theories claim essentially the opposite—that pressure prompts individuals to attend closely to skill processes in a manner that disrupts execution. Although both mechanisms have been shown to occur in certain contexts, it is unclear when distraction and/or explicit monitoring will ultimately impact performance. The authors propose that aspects of the pressure situation itself can lead to distraction and/or explicit monitoring, differentially harming skills that rely more or less on working memory and attentional control. In Experiments 1–2, it is shown that pressure that induces distraction (involving performance-contingent outcomes) hurts rule-based category learning heavily dependent on attentional control. In contrast, pressure that induces explicit monitoring of performance (monitoring by others) hurts information-integration category learning thought to run best without heavy demands on working memory and attentional control. In Experiment 3, the authors leverage knowledge about how specific types of pressure impact performance to design interventions to eliminate choking. Finally, in Experiment 4, the selective effects of monitoring-pressure are replicated in a different procedural-based task: the serial reaction time task. Skill failure (and success) depends in part on how the performance environment influences attention and the extent to which skill execution depends on explicit attentional control. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Individual differences in the efficiency of word recognition.

Examined the hypothesis that the attentional demands of word recognition covary with other measures of reading efficiency. Individual differences in efficiency were indexed by (1) speed and accuracy of lexical access, (2) obligatory activation of phonological codes, and (3) working memory capacity. The attentional demands of word recognition were measured with a dual-task technique. Ss performed naming and probe-detection tasks separately (single task) and in combination (dual task). The results showed that single-task to dual-task decrements in performance on the naming and probe tasks were predicted by measures of the speed and accuracy of lexical access, obligatory activation of phonological codes, and efficiency of working memory. These findings provide support for the widespread assumption that the attentional demands of basic reading processes are a source of individual differences in reading skill. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An attention-based associative account of adjacent and nonadjacent dependency learning.

In 5 experiments, results showed that when participants are faced with materials embedding relations between both adjacent and nonadjacent elements, they learn exclusively the type of relations they had to actively process in order to meet the task demands, irrespective of the spatial contiguity of the paired elements. These results are consonant with current theories positing that attention is a necessary condition for learning. More important, the results provide support for a more radical conception, in which the joint attentional processing of 2 events is also a sufficient condition for learning the relation between them. The well-documented effect of contiguity could be a by-product of the fact that attention generally focuses on contiguous events. This reappraisal considerably extends the scope of approaches based on associative or statistical processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of reducing attentional resources on implicit and explicit memory after severe traumatic brain injury.

Implicit and explicit memory were examined in individuals with severe traumatic brain injury (TBI) under conditions of full and divided attention. Participants included 12 individuals with severe TBI and 12 matched controls. In Experiment 1, participants carried out an implicit test of word-stem completion and an explicit test of cued recall. Results demonstrated that TBI participants exhibited impaired explicit memory but preserved implicit memory. In Experiment 2, a significant reduction in the explicit memory performance of both TBI and control participants, as well as a significant decrease in the implicit memory performance of TBI participants, was achieved by reducing attentional resources at encoding. These results indicated that performance on an implicit task of word-stem completion may require the availability of additional attentional resources that are not preserved after severe TBI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional and nonattentional forms of sequence learning.

Investigated the hypothesis that sequential patterns of behavior can be learned by 2 independent mechanisms. One requires attention to the relation between successive events, whereas the other operates independently of such attention. In 4 experiments, Ss learned visuospatial sequences in a serial reaction time (RT) task. The relation between attentional and nonattentional learning was explored by assessing the extent to which learning transferred between conditions with or without distraction. Results suggest that attentional and nonattentional learning operate independently, in parallel, do not share information, and represent sequential information in qualitatively different ways. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cortico-striatal contributions to category learning: Dissociating the verbal and implicit systems.

To better characterize the neuropsychological mechanisms of implicit and verbalizable category learning, the author studied weather prediction task (WPT) and information integration task (IIT) performance in patients with Parkinson's disease (PD) and healthy older and younger adults. Both older adults and patients with PD were impaired on the WPT, but only patients were impaired on the IIT, suggesting the 2 tasks rely on dissociable systems. Whereas the IIT appeared to rely on implicit processes, results suggest WPT classification depends on explicit processes. Awareness of underlying structure, hypothesis testing ability, and working memory capacity were all related to accuracy on the WPT but not the IIT. The variability commonly noted in WPT performance may reflect individual differences in hypothesis testing ability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Which attention is needed for implicit sequence learning?

The role of attention in implicit sequence teaming was investigated in 3 experiments in which participants were presented with a serial reaction time (SRT) task under single- or dual-task conditions. Unlike previous studies using this paradigm, these experiments included only probabilistic sequences of locations and arranged a counting task performed on the same stimulus on which the SRT task was being carried out. Another sequential contingency was also arranged between the dimension to be counted and the location of the next stimulus. Results indicate that the division of attention barely affected teaming but that selective attention to the predictive dimensions was necessary to learn about the relation between these dimensions and the predicted one. These results are consistent with a theory of implicit sequence teaming that considers this teaming as the result of an automatic associative process running independently of attentional load, but that would associate only those events that are held simultaneously in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A study of performance on tests from the CANTAB battery sensitive to frontal lobe dysfunction in a large sample of normal volunteers: implications for theories of executive functioning and cognitive aging. Cambridge Neuropsychological Test Automated Battery

Several tests from the CANTAB neuropsychological test battery previously shown to be sensitive to frontal lobe dysfunction were administered to a large group of normal volunteers (N = 341) ranging in age from 21 to 79 years. The main tests included a computerized form of the Tower of London test of planning, a self-ordered spatial working memory task, and a test of attentional set formation and shifting. A computerized form of the Corsi spatial span task was also given. Age-related graded declines in performance were seen, sometimes in a discontinuous manner, especially for the attentional set shifting task (at the extradimensional shift stage). Patterns of deficits reminiscent of frontal lobe or basal ganglia damage were observed in the oldest age group (74-79). However, overall the data were only partially consistent with the hypothesis that frontal lobe functions are the most sensitive to effects of aging. Factor analyses showed that performance in the executive tests was not simply related to a measure of fluid intelligence, and their performance had a factor loading structure distinct from that for the CANTAB tests of visual memory and learning previously administered to the same sample. Finally, only limited support was found for the hypothesis that cognitive aging depends on slowed information processing.     

Dilution, not load, affects distractor processing.

Lavie and Tsal (1994) proposed that spare attentional capacity is allocated involuntarily to the processing of irrelevant stimuli, thereby enabling interference. Under this view, when task demands increase, spare capacity should decrease and distractor interference should decrease. In support, Lavie and Cox (1997) found that increasing perceptual load by increasing search set size decreased interference from an irrelevant distractor. In three experiments, we manipulated the cue set size (number of cued locations) independently of the display set size (number of letters presented). Increasing the display set size reduced distractor interference regardless of whether the additional letters were relevant to the task. In contrast, increasing the cue set size increased distractor interference. Both findings are inconsistent with the load explanation, but are consistent with a proposed two-stage dilution account. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Eye Gaze and Individual Differences Consistent With Learned Attention in Associative Blocking and Highlighting.

The associative learning effects called blocking and highlighting have previously been explained by covert learned attention, but evidence for learned attention has been indirect, via models of response choice. The present research reports results from eye tracking consistent with the attentional hypothesis: Gaze duration is diminished for blocked cues and augmented for highlighted cues. If degree of attentional learning varies across individuals but is relatively stable within individuals, then the magnitude of blocking and highlighting should covary across individuals. This predicted correlation is obtained for both choice and eye gaze. A connectionist model that implements attentional learning is shown to fit the data and account for individual differences by variation in its attentional parameters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention and verbal learning in patients with chronic fatigue syndrome

Former neuropsychological studies with Chronic Fatigue Syndrome (CFS) patients evaluated a broad range of cognitive functions. Several, but not all, reported subtle attentional and memory impairments suggesting possible mild cerebral involvement. In this study, a battery of attentional tests and a verbal memory task were administered to 20 CFS patients and 22 healthy controls (HC) in order to clarify the specific nature of attention and memory impairment in these patients. The results provide evidence for attentional dysfunction in patients with CFS as compared to HC. CFS patients performed more poorly on a span test measuring attentional capacity and working memory. Speeded attentional tasks with a more complex element of memory scanning and divided attention seem to be a sensitive measure of reduced attentional capacity in these patients. Focused attention, defined as the ability to attend to a single stimulus while ignoring irrelevant stimuli, appears not to be impaired. CFS patients were poorer on recall of verbal information across learning trials, and poor performance on delayed recall may be due to poor initial learning and not only to a retrieval failure.     

Attention moderates the processing of inhibitory information in primary psychopathy.

Primary psychopathic individuals are less apt to reevaluate or change their behavior in response to stimuli outside of their current focus of attention. According to the response modulation hypothesis, this tendency reflects a lack of responsivity to important peripheral information and undermines adaptive self-regulation. To evaluate this hypothesis, the authors administered a response competition (flanker-type) task and manipulated focus of visual attention. They predicted that psychopathic individuals would display significantly less interference to response incongruent information than nonpsychopathic participants when attention was cued to the target location but display normal interference when there was no prepotent focus of attention. The results confirmed this hypothesis and are consistent with the contention that attention moderates psychopathic individuals’ responsivity to inhibitory cues. Implications of this attentional anomaly for psychopathic traits and behavior are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When implicit learning fails: amnesia and the problem of error elimination

We propose that one of the major functions of explicit memory is the elimination of learning errors. The hypothesis is explored by means of a stem completion task in which subjects are presented with stems having many potential completions, and in the initial phase are either encouraged to guess, the "errorful" procedure, or are provided with the correct completion, the "errorless" condition. Learning is then tested over a sequence of nine trials. The performance of amnesic subjects who are assumed to have good implicit but bad explicit learning is compared with that of normal elderly subjects, who are assumed to have an intermediate level of explicit learning skill, and young controls who are expected to be high in both implicit and explicit learning capacity. As predicted, errorless learning is beneficial, with the effect being particularly marked for the amnesic group. A detailed analysis of the intrusion errors supports an interpretation of the results in terms of the relative contribution to the three groups of implicit learning, which is assumed to be particularly vulnerable to interference. Implications for the analysis of normal learning, and for the rehabilitation of brain damaged patients are discussed.