Learning to utilize information presented over two sensory channels

In three separate experiments, Ss were provided with auditory, visual, or simultaneous auditory and visual information in a classification task. Difficulty of classification was manipulated by varying the stimulus exposure duration. Consistent bisensory facilitation effects were noted for later trials, with interference evident on earlier trials. Exposure duration influenced rate and not amount of learning, with bisensory performance being most affected by duration. A transfer paradigm was used in Experiment III, and little if any transfer was noted between unisensory and bisensory stimulus conditions. It was concluded that Ss were extracting the most salient bisensory stimulus components from the auditory and visual modes of information into a unidimensional information configuration.     

Cross-modal re-mapping influences the Simon effect

Tagliabue, Zorzi, Umiltà, and Bassignani (2000) showed that one's practicing of a spatially incompatible task influences performance in a Simon task even when the interval between the two tasks is as long as 1 week. In the present study, three experiments were conducted to investigate whether such an effect could be found in a cross-modal paradigm, whereby stimuli in the two tasks were presented in different modalities. Subjects performed either compatible or incompatible mappings in an acoustic spatial compatibility task and, after an interval of 5 min, 24 h, or 7 days, performed a visual Simon task. Results show that the spatially incompatible mapping task affected performance in the Simon task: The Simon effect was absent for all three intervals. This pattern is similar to the results of the Tagliabue et al. study, in which both tasks were performed in the same (visual) modality. Our findings disprove possible explanations based on episodic/contextual effects and support the hypothesis of a long-lasting spatial remapping that is not modality specific.     

Role of multiple resources in predicting time-sharing efficiency: evaluation of three workload models in a multiple-task setting

The goal of our study was to assess the validity of the assumptions underlying three prominent workload models: the Time-Line Analysis and Prediction workload model (Parks & Boucek, 1989), the VACP workload model (Aldrich, Szabo, & Bierbaum, 1989), and the W/INDEX model (North & Riley, 1989). Sixteen subjects flew a low-fidelity flight simulation. Subjects were required to perform a two-axis tracking task, a concurrent visual-monitoring task, and a discrete decision task. The decision task had 16 variations defined by two levels on each of the following dimensions: input modality (visual vs. auditory), processing code (spatial vs. verbal), difficulty (easy vs. hard), and response modality (manual vs. voice). Dual-task costs were found only for the tracking task. The tracking data were then analyzed using two approaches: a traditional analysis of variance (ANOVA) and a correlational analysis of tracking performance versus model predictions. The ANOVA revealed that performance on the tracking task was better when the concurrent decision task was responded to vocally and was easy. Input modality and processing code of the concurrent decision task had no significant effect on tracking performance. The correlational analysis was used to evaluate each of the three models, to determine what features were responsible for improving the models' fit, and to compare their performance with a pure time-line model that makes no multiple-resource assumptions. All three models did a good job of predicting variance between experimental conditions, accounting for between 56% and 84% of the variance in our data and between 10% and 40% of an earlier data set. Different features of each model that affect the fit are then discussed. We conclude that it is important for models to retain a multiple-resource coding, although the best features of that coding remain to be determined. Coding tasks by their demand level appears to be less critical.     

Unisensory and bisensory perceptual and memory processing in stuttering adults and normal speakers

The perceptual/memory process abilities of adult stutterers were compared with those of normal adult speakers. Unisensory tasks were used as standards for comparison of the simultaneous, bisensory processes. Subjects were tested individually on sensory oral form, manual form, and word recall tasks followed by combinations of word recall and oral form discrimination, and word recall and manual form discrimination. Four bisensory combinations were tested, and in each test subjects were asked for the discrimination of the forms or recall of the words. Results showed that on both bisensory tasks in which the subjects were asked for the words rather than the form discrimination the stutterers were significantly poorer than the normals. On the bisensory tasks in which the forms were called for, the stutterers' performances were equal to the normals. No differences were found between the groups on the three unisensory tasks. These findings are related to some processing theories and to EEG studies of word recall in adult stutterers.     

Working memory in chess

Three experiments investigated the role of working memory in various aspects of thinking in chess. Experiment 1 examined the immediate memory for briefly presented chess positions from master games in players from a wide range of abilities, following the imposition of various secondary tasks designed to block separate components of working memory. Suppression of the articulatory loop (by preventing subvocal rehearsal) had no effect on measures of recall, whereas blocking the visuospatial sketchpad (by manipulation of a keypad) and blocking the central executive (by random letter generation) had equivalent disruptive effects, in comparison with a control condition. Experiment 2 investigated the effects of similar secondary tasks on the solution (i.e., move selection) of tactical chess positions, and a similar pattern was found, except that blocking the central executive was much more disruptive than in Experiment 1. Experiment 3 compared performance on two types of primary task, one concerned with solving chess positions as in Experiment 2, and the other a sentence-rearrangement task. The secondary tasks in each case were both designed to block the central executive, but one was verbal (vocal generation of random numbers), while the other was spatial in nature (random generation of keypresses). Performance of the spatial secondary task was affected to a greater extent by the chess primary task than by the verbal primary task, whereas there were no differential effects on these secondary tasks by the verbal primary task. In none of the three experiments were there any differential effects between weak and strong players. These results are interpreted in the context of the workingmemory model and previous theories of the nature of cognition in chess.     

Shadowing in bisensory memory

Shadowing (vocalization-at-presentation) was applied to a bisensory situation where different messages were simultaneously presented to the visual and auditory modalities. Three groups of subjects were employed: Group I shadowed the visual modality; Group II shadowed the auditory modality; Group III was a control, shadowing neither modality. Shadowing in the present experiment facilitated recall of the shadowed modality, particularly the visual modality, which is usually inferior to auditory recall.

It also became apparent that visual recall in an ordinary bisensory situation was minimal if not near an incidental level and that a true bisensory situation with equal division of attention between the two modalities employed does not exist.     

Evidence for modality-independent order coding in working memory

The aim of the present study was to investigate the representation of serial order in working memory, more specifically whether serial order is coded by means of a modality-dependent or a modality-independent order code. This was investigated by means of a series of four experiments based on a dual-task methodology in which one short-term memory task was embedded between the presentation and recall of another short-term memory task. Two aspects were varied in these memory tasks—namely, the modality of the stimulus materials (verbal or visuo-spatial) and the presence of an order component in the task (an order or an item memory task). The results of this study showed impaired primary-task recognition performance when both the primary and the embedded task included an order component, irrespective of the modality of the stimulus materials. If one or both of the tasks did not contain an order component, less interference was found. The results of this study support the existence of a modality-independent order code.     

Stimulus intensity and foreperiod effects in intersensory facilitation

Intersensory facilitation refers to the more rapid reaction time (RT) to a target in one modality and an accessory stimulus in a different modality compared to a RT to the target alone. Prior studies suggest two processes contribute to the phenomenon, termed the preparatory state and energy integration which refer to the action of accessory stimulation in providing forewarning and intensifying the reaction signal, respectively. Experiment I factorially varied foreperiod duration, light (target) intensity and tone (accessory) intensity in a discriminative RT task. The results were that foreperiod (preparatory state) and intensity (energy integration) effects were additive, implying that they affected separate processing stages. Accessory stimulus intensity affected false alarm rate on catch trials. This suggests that energy integration involves a form of response bias (increased likelihood of responding) and not facilitation (more rapid information processing). Experiment II indicated that comparable energy integration effects obtain with tone as target and light as accessory, as well as vice versa. The findings further indicated that RT to a bisensory pairing is more rapid when attention is directed to the more potent member of the pair.     

The interaction between emotion and executive control: Comparison between visual,auditory, and tactile modalities

The reciprocal connections between emotion and attention are vital for adaptive behaviour. Previous results demonstrated that the behavioural effects of emotional stimuli on performance are attenuated when executive control is recruited. The current research studied whether this attenuation is modality dependent. In two experiments, negative and neutral pictures were presented shortly before a visual, tactile, or auditory target in a Simon task. All three modalities demonstrated a Simon effect, a conflict adaptation effect, and an emotional interference effect. However, the interaction between picture valence and Simon congruency was found only in the visual task. Specifically, when the Simon target was visual, emotional interference was reduced during incongruent compared to congruent trials. These findings suggest that although the control-related effects observed in the Simon tasks are not modality dependent, the link between emotion and executive control is modality dependent. Presumably, this link occurs only when the emotional stimulus and the target are presented in the same modality.     

Texture-based tasks are little affected by second tasks requiring peripheral or central attentive fixation.

Experiments are described in which observers attempted to perform concurrently two separate visual tasks. Two types of tasks were used: the identification of a T-shaped or L-shaped letter target, and the detection or localization of a texture element of unique orientation (texture target) within a dense texture. Combining these tasks to form various task pairs, performance as a function of stimulus onset asynchrony (SOA) was established separately for each task in a pair. In addition, performance was measured when each task was carried out by itself. When paired, two identification tasks (T or L) on (two) letter targets required a significantly larger SOA than either identification task by itself. This outcome suggests the involvement of serial performance and competition for a limited resource, confirming that letter identification requires attentive fixation. However, when the identification of a central letter target was paired with the localization (upper or lower hemifield) of an eccentric texture target, performance in the pair was comparable to performance of each task by itself. This suggests parallel performance and a lack of conflict over resources. The outcome was similar when the identification of an eccentric letter target was paired with the detection (present or absent) of an eccentric texture target. These results are consistent with the possibility that localization and detection of a textural singularity do not require attentive fixation.     

Evidence for modality-independent order coding in working memory

The aim of the present study was to investigate the representation of serial order in working memory, more specifically whether serial order is coded by means of a modality-dependent or a modality-independent order code. This was investigated by means of a series of four experiments based on a dual-task methodology in which one short-term memory task was embedded between the presentation and recall of another short-term memory task. Two aspects were varied in these memory tasks--namely, the modality of the stimulus materials (verbal or visuo-spatial) and the presence of an order component in the task (an order or an item memory task). The results of this study showed impaired primary-task recognition performance when both the primary and the embedded task included an order component, irrespective of the modality of the stimulus materials. If one or both of the tasks did not contain an order component, less interference was found. The results of this study support the existence of a modality-independent order code.     

自我损耗的视听通道效应

采用双任务实验范式,通过两个实验探讨了自我损耗的通道效应。实验1考察了完成视听工作记忆任务对执行手柄任务（非视听任务）的影响,结果发现,完成视觉损耗任务导致手柄任务的成绩显著地变差,完成听觉损耗任务、视听非损耗任务均对手柄任务的成绩没有影响。实验2考察了完成视听工作记忆任务对执行Stroop任务（视觉任务）的影响,结果发现,完成视觉损耗任务导致Stroop任务的成绩显著地变差,完成听觉损耗任务、视听非损耗任务对Stroop任务的成绩没有影响。研究结果表明同一自我控制任务通过视听通道完成对随后另一自我控制任务的影响不同,证实了自我损耗的视听通道效应。     

The identification and transfer of timesharing skills

Performance on two different task combinations was examined for evidence that timesharing skills are learned with practice and can transfer between task combinations. One combination consisted of two discrete informaion processing tasks, a short-term memory task and a classification task; the other consisted of two identical one-dimensional compensatory tracking tasks. Three groups of 16 subjects were employed in the experiment. The first received dual-task training on both combinations; the second received single-task training on the discrete-task combination and dual-task training on the tracking combination; the third received dual-task training on the tracking combination only. Evidence for distinct timesharing skills was found in both combinations using a new technique designed to separate improvements in timesharing skills from improvements in single-task performance. Transfer of timesharing skills also was found. Several fine-grained analyses performed on the data from the discrete task combination and a Control Theory Analysis of the tracking data indicated that skills in parallel processing were learned in each combination and transferred between them.     

Subjective pictorial information and visual search

The effects of a combination of variables previously studied in ordinary and dichotic immediate memory were examined in bisensory memory, wherein the visual and auditory modalities were employed. These variables. combined in a factorial design. were: (1) type of material; (2) rate of presentation of material; (3) order of recall for a modality. either first or second; (4) locus of instructions about order of report; and (5) overall differences in memory for each modality. The variables of instruction, order of report, and nature of materials yielded effects in the bisensory situation similar to those reported for the dichotic and ordinary immediate memory situations. On the other hand. interference effects due to the combination of materials in the two channels were practically nonexistent. Additionally, when the modalities were stimulated simultaneously each displayed curves predictable from data obtained when it was explored independently of the other modality.     

Cognitive consequences of congenital deafness

Comparing congenitally deaf children with hearing children on a variety of information processing tasks provides a natural test of the developmental consequences accompanying the long term loss of a particular sensory input. In this experiment, two sequential and two spatial tasks were used to evaluate the way deaf and hearing individuals process these different types of information. When deaf students were asked to recall the order of a string of lights, they performed as well as hearing students. Deaf students were at a significant disadvantage, however, when processing sequentially presented digits. Deaf students performed as well as hearing students on two complex, standardized spatial tasks. The loss of a major sensory modality had minimal effect on three of the four tasks investigated in the present study. Explanations for the single task with a performance differential are considered.     

An automated system for administering continuous workload and for measuring sustained continuous performance

Sustained continuous performance for up to 42 h was studied with 60 male volunteers in two separate protocols. The recuperative value of six 1-h nap breaks and a single 6-h nap break were contrasted in 20 subjects, 10 in each nap group. Forty other subjects attempted to work continuously with no breaks for 42 h. Twenty of these subjects worked simultaneously on separate parallel computer-based tasks, but worked in the same room in pairs. All subjects in the two nap groups (N=10 and N=10), as well as 20 who had no scheduled breaks, worked alone, almost isolated, with minimal interaction with the experimenters. During each 10 min, subjects performed a tracking task, a pattern-memory task, and an addition task and provided subjective ratings on sleepiness and attention/fantasy. Results showed that computerized tasks demanding sustained continuous performance without naps cause more rapid performance deterioration than previously tested intermittent-work paradigms.     

Individual Differences in Attentional Strategies in Multitasking Situations

This study compared attentional strategies in prioritized and unprioritized multitasking situations using individual differences in the Type A behavior pattern (TABP) as predictors. The study expanded previous studies by using a triple task situation that presented two visual tasks and one auditory task simultaneously. One hundred and eighteen undergraduate students were utilized. One group received instructions for all tasks and their relative importance to each other for achieving a full performance score. The other group received instructions for the visual tasks only, and no information about their relative importance was given, creating ambiguity about priorities among the tasks. Global TABP and its subcomponents (i.e., time urgency, achievement strivings, impatience or irritability, polychronicity) were utilized as predictors of task performance. Significant correlations were found between the TABP subcomponents and different performance indexes, but such a relation was not found between global TABP and performance. Applied implications of these findings and directions for the future research are discussed.     

The Effects of Monitoring Individual and Group Performance on the Distribution of Effort Across Tasks1

This study was concerned with the mechanism(s) via which performance monitoring affects task performance. To investigate whether an individual's concerns over the evaluation of his or her performance underlie the effects of performance monitoring (independent of contingent consequences) on the distribution of effort across tasks, the study examined whether the way in which individuals performed two tasks was differentially affected by the way in which supervisors monitored performance on those tasks. Subjects working in a group setting performed two different tasks for 90 minutes, their instructions being to perform as well as possible on each task. When supervisors periodically monitored the work output of each individual within the group on one of the two tasks, subjects perceived that the supervisor was evaluating and comparing individual performance, and produced more on the monitored task at the expense of the unmonitored task. When, however, the supervisor's monitoring focused on group rather than individual products, subjects perceived that the supervisor was less likely to be able to evaluate and to compare individual performance, and their performance on the two tasks was the same, regardless of which task was monitored. Path analysis supported the interpretation that the effects of monitoring on performance were mediated by evaluation concerns associated with performance on each task.