Specificity and transfer effects in time production skill: examining the role of attention

Two experiments examined transfer of a prospective, time production skill under conditions involving changes in concurrent task requirements. Positive transfer of the time production skill might be expected only when the attentional demands of the concurrent task were held constant from training to test. However, some positive transfer was found even when the concurrent task at retraining was made either easier or more difficult than the concurrent task learned during training. The amount and direction of transfer depended more on the pacing of the stimuli in the secondary task than on the difficulty of the secondary task, even though difficulty affects attentional demands more. These findings are consistent with the procedural reinstatement principle of skill learning, by which transfer from one task to another depends on an overlap in procedures required by the two skills.     

Attentional resources in timing: Interference effects in concurrent temporal and nontemporal working memory tasks

Three experiments examined interference effects in concurrent temporal and nontemporal tasks. The timing task in each experiment required subjects to generate a series of 2- or 5-sec temporal productions. The nontemporal tasks were pursuit rotor tracking (Experiment 1), visual search (Experiment 2), and mental arithmetic (Experiment 3). Each nontemporal task had two levels of difficulty. All tasks were performed under both single- and dual-task conditions. A simple attentional allocation model predicts bidirectional interference between concurrent tasks. The main results showed the classic interference effect in timing. That is, the concurrent nontemporal tasks caused temporal productions to become longer (longer productions represent a shortening of perceived time) and/or more variable than did timing-only conditions. In general, the difficult version of each nontemporal task disrupted timing more than the easier version. The timing data also exhibited a serial lengthening effect, in which temporal productions became longer across trials. Nontemporal task performance showed a mixed pattern. Tracking and visual search were essentially unaffected by the addition of a timing task, whereas mental arithmetic was disrupted by concurrent timing. These results call for a modification of the attentional allocation model to incorporate the idea of specialized processing resources. Two major theoretical frameworks—multiple resource theory and the working memory model—are critically evaluated with respect to the resource demands of timing and temporal/ nontemporal dual-task performance.     

Prospective Memory and Divided Attention

In three experiments, we manipulated the processing demands of a concurrent task to test the hypothesis that an event-based prospective memory task satisfies a criterion of automaticity proposed by Hasher and Zacks (1979). As in the previous studies, a prospective memory task (pressing a key whenever a target word was presented) was embedded within a short-term memory task (remembering seven words). In addition, participants performed a concurrent memory task which varied in difficulty. Participants repeated either 0 to 6 randomly generated digits or a single word. In all three experiments, short-term memory performance was influenced by the concurrent memory load. Prospective performance, in contrast, was not affected by the memory load even though an attempt was made to increase the difficulty of the prospective task by manipulating the specificity of the target instructions (Experiment 2) and the number of target words (Experiments 2 and 3). The results are discussed within the framework of automatic processing.     

A common source of attention for auditory and visual tracking

Tasks that require tracking visual information reveal the severe limitations of our capacity to attend to multiple objects that vary in time and space. Although these limitations have been extensively characterized in the visual domain, very little is known about tracking information in other sensory domains. Does tracking auditory information exhibit characteristics similar to those of tracking visual information, and to what extent do these two tracking tasks draw on the same attention resources? We addressed these questions by asking participants to perform either single or dual tracking tasks from the same (visual–visual) or different (visual–auditory) perceptual modalities, with the difficulty of the tracking tasks being manipulated across trials. The results revealed that performing two concurrent tracking tasks, whether they were in the same or different modalities, affected tracking performance as compared to performing each task alone (concurrence costs). Moreover, increasing task difficulty also led to increased costs in both the single-task and dual-task conditions (load-dependent costs). The comparison of concurrence costs between visual–visual and visual–auditory dual-task performance revealed slightly greater interference when two visual tracking tasks were paired. Interestingly, however, increasing task difficulty led to equivalent costs for visual–visual and visual–auditory pairings. We concluded that visual and auditory tracking draw largely, though not exclusively, on common central attentional resources.     

How is performance limited: Testing the notion of central capacity

Two-dimensional pursuit tracking task was employed in three experiments designed to test three predictions of the central capacity model of performance limitations under time-sharing conditions. These are the predicted effects of change in task difficulty, task emphasis and their interaction. Each of simultaneously performed tracking dimensions (horizontal and vertical) was treated as a separate task and manipulated independently. Tracking difficulty on each dimension and their relative emphasis were jointly manipulated. When frequency or velocity of target movement served as difficulty parameters, and control complexity was relatively low, tradeoffs between dimensions in different priority conditions were small and task difficulty had no effect on the performance of the concurrent task, neither did it interact with task emphasis. When control complexity was increased and in addition was manipulated as the difficulty parameter, linear tradeoff was observed and difficulty seemed to interact with task emphasis. These results cannot be easily accommodated within a strict central capacity model. An alternative interpretation based on a multiple capacity approach is outlined.     

A dual task response modality effect: Support for multiprocessor models of attention

In Experiment I two groups of 11 men performed a continuous visual input/manual output task simultaneously with a two-choice tone identification task. One group responded vocally to the tones; one group responded with the hand not involved in the continuous tracking task. In either perceptual or stimulus uncertainty terms the two combinations were identical; the only difference between them was the modality of the two-choice responses. The continuous task was performed significantly worse when the two-choice responses were manual. The probability of response production on the continuous task was affected by the production of manual responses but not by the production of vocal responses. It was concluded that although the two manual responses were produced by a single limited capacity process, the manual and vocal responses were produced by independent processes. In Experiment II the same manual tracking task was combined with a mental arithmetic task at two levels of difficulty. Tracking performance was independent of the difficulty of the arithmetic task. These results support a multi-processor approach to attention as opposed to single channel models. Results of dual task studies which have used only one pair of response modalities are re-examined in the light of the response modality effect found in Experiment I.     

Temporal characteristics of primary-secondary message interference in a dichotic listening task

Previous experiments have shown that during performance of a shadowing task the unattended message is processed at a semantic level. Four experiments are reported that deal with the question of how processing of the unattended message influences the difficulty of shadowing the attended message. Experiment I demonstrated that pupil dilation measures the difficulty associated with a shadowing task. In Experiment II it was shown that during shadowing of 20-item lists pupil dilation decreases as shadowing continues when either words or white noise are in the unattended channel. These results support the idea that it takes time for the attentional mechanism to focus on the attended message. In Experiments III and IV it was found that this decrease in difficulty of shadowing is much less when the attended and unattended messages come from the same stimulus category (letter-letter, digit-digit). The results indicate that, when the unattended message is from the same stimulus category as the attended message, it can interfere with the ability of the attentional system to focus on the attended message.     

Residual attentional capacity amongst young and elderly during dual and triple task walking

Walking is considered an automatic function which demands little attentional resources. Thus a residual attentional capacity is available for a concurrent task (dual task). Minor age-related deficits in postural control may minimize the residual attentional capacity, however this may not be detected by a simple examination of the individuals gait performance. This study investigated the use of challenging dual task combinations to detect age related changes in gait performance. Eleven community-dwelling elderly (mean age 76 years) and 13 young subjects (mean age 26 years) participated in the study. The participants walked along a figure-of-eight track at a self-selected speed. The effect of introducing a concurrent cognitive task and a concurrent functional motor task was evaluated. Stride-to-stride variability was measured by heel contacts and by trunk accelerometry. In response to the cognitive task the elderly increased their temporal stride-to-stride variability by 39% in the walking task and by 57% in the combined motor task. These increases were significantly larger than observed for the young. Equivalent decreases in trunk acceleration autocorrelation coefficients and gait speed were found. A combination of sufficiently challenging motor tasks and concurrent cognitive tasks can reveal signs of limited residual attentional capacity during walking amongst the elderly.     

The role of metacognition in prospective memory: Anticipated task demands influence attention allocation strategies

The present study investigates how individuals distribute their attentional resources between a prospective memory task and an ongoing task. Therefore, metacognitive expectations about the attentional demands of the prospective-memory task were manipulated while the factual demands were held constant. In Experiments 1a and 1b, we found attentional costs from a prospective-memory task with low factual demands to be significantly reduced when information about the low to-be-expected demands were provided, while prospective-memory performance remained largely unaffected. In Experiment 2, attentional monitoring in a more demanding prospective-memory task also varied with information about the to-be-expected demands (high vs. low) and again there were no equivalent changes in prospective-memory performance. These findings suggest that attention–allocation strategies of prospective memory rely on metacognitive expectations about prospective-memory task demands. Furthermore, the results suggest that attentional monitoring is only functional for prospective memory to the extent to which anticipated task demands reflect objective task demands.     

Time estimation and concurrent nontemporal processing: Specific interference from short-term-memory demands

Previous studies have shown that the effect of concurrent nontempcraLprocessmg on time astimation may vary depending on the level of difficulty of the nontemporal task. This is commonly interpreted within the context of so-called distraction/interruption models of temporal processing, which propose that as concurrent task difficulty or complexity is increased, temporal processing receives less attention. We hypothesize that the effect of nontemporal processing does not depend on the level of difficulty as such, but rather on the extent to which the concurrent nontemporal task specifically involves processing in short-term meraery. Four experiments were run in which the short-term memory requirements of concurrent tasks were systematically varied, although all of the tasks were of comparable levels of difficulty. In the first experiment, the effect of memory search on simultaneous temporal productions was proportional to the number of items to search. As with reaction time, produced intervals were shown to increase linearly with the number of items in the memorized set. In Experiment 2, a visual search involving some load on short-term memory interfered in the same way with time production, although to a lesser extent. The last two experiments showed that performing attention-demanding visual search tasks that did not involve short-term memory did not lengthen simultaneously produced time inter-vals. This suggests that interference of nontemporal processing on time processing may not be a matter of nonspecific general purpose attentional resources, but rather of concurrent short-term-memory processing demands.     

Processing of stimulus properties: evidence for dual-task integrality

The conditions under which dual-task integrality can be fostered were assessed in a study in which we manipulated four factors likely to influence the integrality between tasks: intertask redundancy, the spatial proximity of primary and secondary task displays, the degree to which primary and secondary task displays constitute a single object, and the resource demands of the two tasks. The resource allocation policy is inferred from changes in the amplitude of the P300 component of the event-related brain potential. Twelve subjects participated in three experimental sessions in which they performed both single and dual tasks. The primary task was a pursuit step tracking task. The secondary tasks required subjects to discriminate between different intensities or different spatial positions of a stimulus. Task pairs that required the processing of different properties of the same object resulted in better performance than task pairs that required the processing of different objects. Furthermore, these same object task pairs led to a positive relation between primary task difficulty and the resources allocated to secondary task stimuli. Intertask redundancy and the physical proximity of task displays produced similar effects of reduced magnitude.     

The distribution of attention within objects in multiple-object scenes: prioritization by spatial probabilities and a center bias

This study investigates how the attentional distribution within objects is affected by spatial probabilities, bias toward objects' centers (Alvarez & Scholl, 2005), and object motion. In a multiple-object tracking task, observers tracked line objects while simultaneously detecting probes appearing on the objects. Experiments 1 and 2 manipulated the probabilities of probes appearing at the centers and ends of objects. Overall, probe detection was better at centers than at ends, but it was also affected by probe location probabilities; when probe locations were 100% certain, the center advantage was eliminated. Experiment 3 manipulated rotational, translational, and size-change components of object motion. The center advantage still occurred with stationary objects, and its magnitude was not affected by different motion types. These results indicate that attention is biased toward the centers of objects in multiple-object scenes, both for stationary and moving objects. They also imply that attentional prioritizations based on spatial probabilities can accompany moving objects.     

Attentional capture is contingent on the interaction between task demand and stimulus salience

The aim of this research was to investigate the potential impacts of task demand and stimulus salience on the stimulus-driven attentional capture effect. The participants performed an inefficient visual search task while an irrelevant luminance singleton was present. In Experiment 1, the task demand was manipulated while the stimulus salience of the irrelevant singleton was fixed. With the same salient singleton, the attentional capture effect was observed in the low-difficulty condition but disappeared in the high-difficulty condition. In Experiment 2, the stimulus salience was manipulated while the task demand was fixed. With the same task, the highly salient singleton captured attention, whereas the relatively lowly salient singleton could not. In Experiment 3, both task demand and stimulus salience were manipulated simultaneously. The stimulus-driven attentional capture effect by the irrelevant singleton increased not only as the task demand decreased but also as the stimulus salience increased. The present study might provide a way to reconcile conflicting findings in the attentional capture literature; the underlying neural mechanism is discussed. 2009 The Psychonomic Society, Inc.     

Investigating the visual span in comparative search: the effects of task difficulty and divided attention

In three experiments, participants' visual span was measured in a comparative visual search task in which they had to detect a local match or mismatch between two displays presented side by side. Experiment 1 manipulated the difficulty of the comparative visual search task by contrasting a mismatch detection task with a substantially more difficult match detection task. In Experiment 2, participants were tested in a single-task condition involving only the visual task and a dual-task condition in which they concurrently performed an auditory task. Finally, in Experiment 3, participants performed two dual-task conditions, which differed in the difficulty of the concurrent auditory task. Both the comparative search task difficulty (Experiment 1) and the divided attention manipulation (Experiments 2 and 3) produced strong effects on visual span size.     

Automaticity versus timesharing in timing and tracking dual-task performance

Two experiments investigated the interfering effects of a manual tracking task on timing performance. Subjects generated a series of 5-s temporal productions under control (timing only) and experimental (timing + pursuit rotor tracking) conditions. Timing was more variable under experimental conditions, a finding consistent with attentional models which argue that timing tasks compete with concurrent distractor tasks for limited processing resources. A pretest-posttest paradigm was employed to evaluate the hypothesis that practice on the tracking task would lessen its attentional demands and thereby attenuate the interference effect. Experiment 1 involved single-task practice (tracking alone). Single-task practice leads to automaticity, the ability to perform a skilled task using fewer processing resources. Pretest-posttest comparisons showed that such practice reduced interference in timing. Experiment 2 involved dual-task practice (timing + tracking). Dual-task practice promotes the development of timesharing, the ability to efficiently switch attention between multiple tasks. In this case, practice failed to reduce the interference effect in timing. The results suggest that effective strategies for timing in dual-task situations must allow one to closely monitor the ongoing flow of temporal events. Received: 11 November 1996 / Accepted: 6 May 1997     

An assessment of antecedent events influencing noncompliance in an outpatient clinic

Several studies have shown that various factors can influence noncompliance, including task novelty, rate of presentation, and task preference. This study examined the impact of selected antecedent variables on noncompliance in an outpatient clinic setting. In two experiments involving 6 typically developing children, the consequences for noncompliance remained constant. During Experiment 1, demands that included noncontingent access to adult attention were contrasted with the same demands that did not include attention within a multielement design. In Experiment 2, demands were altered by decreasing the difficulty or amount of work or providing access to attention. In both experiments, results indicated idiosyncratic responses to the manipulated variables, with decreases in noncompliance observed following introduction of one or more antecedent variables with 5 of the 6 participants. These results suggested that noncompliance can be reduced via changes in antecedent variables, including adding potential positive reinforcers to the task situation, and that it is possible to probe variables that alter noncompliance in an outpatient clinic setting.     

Interaction of attentional and motor control processes in handwriting

The interaction between attentional capacity, motor control processes, and strategic adaptations to changing task demands was investigated in handwriting, a continuous (rather than discrete) skilled performance. Twenty-four subjects completed 12 two-minute handwriting samples under instructions stressing speeded handwriting, normal handwriting, or highly legible handwriting. For half of the writing samples, a concurrent auditory monitoring task was imposed. Subjects copied either familiar (English) or unfamiliar (Latin) passages. Writing speed, legibility ratings, errors in writing and in the secondary auditory task, and a derived measure of the average number of characters held in short-term memory during each sample ("planning unit size") were the dependent variables. The results indicated that the ability to adapt to instructions stressing speed or legibility was substantially constrained by the concurrent listening task and by text familiarity. Interactions between instructions, task concurrence, and text familiarity in the legibility ratings, combined with further analyses of planning unit size, indicated that information throughput from temporary storage mechanisms to motor processes mediated the loss of flexibility effect. Overall, the results suggest that strategic adaptations of a skilled performance to changing task circumstances are sensitive to concurrent attentional demands and that departures from "normal" or "modal" performance require attention.     

On the automatic nature of the task-appropriate processing effect in event-based prospective memory

This research tested competing predictions about the cognitive processes underlying the task-appropriate processing effect in prospective memory. Participants had to press a designated key whenever a word from the semantic category of animals or from the structural category of palindromes occurred in an ongoing lexical decision task. The availability of attentional resources was manipulated by varying the effort to the ongoing task in terms of speed or accuracy. In the task-appropriate semantic prospective memory task, performance was robust against the speed versus accuracy instructions. In the task-inappropriate structural prospective memory task, performance declined under speed instructions that detracted attentional resources. Accordingly, a facilitating effect of task-appropriate processing was observed under speed instructions but not accuracy instructions. The results support the notion that the task-appropriate processing effect is due to a larger contribution of automatic cue detection to prospective memory performance under task-appropriate than task-inappropriate conditions.     

Effects of training with added difficulties on RADAR detection

Three experiments simulating military RADAR detection addressed a training difficulty hypothesis (training with difficulty promotes superior later testing performance) and a procedural reinstatement hypothesis (test performance improves when training conditions match test conditions). Training and testing were separated by 1 week. Participants detected targets (either alphanumeric characters or vehicle pictures) occurring among distractors. Two secondary tasks were used to increase difficulty (a concurrent, irrelevant tone‐counting task and a sequential, relevant action‐firing response). In Experiment 1 , involving alphanumeric targets with rapid displays, tone counting during training degraded test performance. In Experiment 2, involving vehicle targets with both sources of difficulty and slower presentation times, training under relevant difficulty aided test accuracy. In Experiment 3, involving vehicle targets and action firing with slow presentation times, test accuracy tended to be worst when neither training nor testing involved difficult conditions. These results show boundary conditions for the training difficulty and procedural reinstatement hypotheses. Copyright © 2010 John Wiley & Sons, Ltd.     

知觉负载、注意定势与选择性注意

本研究采用Eriksen Flanker（侧抑制）范式,将当前任务区分为高、低知觉负载两种条件．并系统操纵边缘视野干扰项与中央靶子的不同加工层次关系,从而考察注意选择的知觉负载理论。实验一发现,高知觉负载情况下没有任何flanker冲突效应,而低知觉负载情况下既有知觉层次和反应层次的冲突效应,也有一致条件下的促进效应。实验二增加了一致条件试次的比例,从而操纵自上而下的注意定势,发现高、低知觉负载情况下都存在知觉冲突效应和一致条件下的促进效应。这些发现表明,对任务无关信息的加工既受到任务相关信息的知觉负载和剩余加工资源的分配的影响,也受到自上而下注意定势的影响;自下而上和自上而下过程相互作用,共同决定加工资源的分配和注意选择的认知阶段。