Effects of practice on task architecture: combined evidence from interference experiments and random-walk models of decision making

Does extensive practice reduce or eliminate central interference in dual-task processing? We explored the reorganization of task architecture with practice by combining interference analysis (delays in dual-task experiment) and random-walk models of decision making (measuring the decision and non-decision contributions to RT). The main delay observed in the Psychologically Refractory Period at short stimulus onset asynchronies (SOA) values was largely unaffected by training. However, the range of SOAs over which this interference regime held diminished with learning. This was consistent with an overall shift observed in single-task performance from a highly variable decision time to a reliable (non-decision time) contribution to response time. Executive components involved in coordinating dual-task performance decreased (and became more stable) after extensive practice. The results suggest that extensive practice reduces the duration of central decision stages, but that the qualitative property of central seriality remains a structural invariant.     

Drivers’ self-reported responses to a potentially realistic fabricated road sign message

This article seeks to understand the potential response of drivers when they encounter compromised Dynamic Message Signs (DMS). The findings are built on the self-reported response of 4,706 participants in a Stated Preference (SP) survey conducted between November 2018 and December 2018 in the United States. The findings show the response of drivers to the “Downtown Under Terrorist Attack” message falls into route divergence, speed change, and distraction, and the likelihood of route divergence, distraction, and a slowdown is significantly more than either stopping or speeding up. The possibility of a response, however, varies depending on socioeconomic characteristics, attitudinal characteristics, and driving behavior. It is highlighted (1) female and young drivers are more probable to detour, to change speed, or to be distracted, (2) drivers who are familiar with DMS, encounter it frequently, or pay attention to its content, have a higher chance of detouring or changing speed, while they are less likely to be distracted, and (3) technology-friendly drivers are likely to detour or slow down. From the distraction model, it is further inferred that drivers are distracted cognitively, visually, and manually. The findings have implications for researchers and federal, state, and local agencies who are aware of the consequences of cybersecurity threats for the operation and profitability of the transport network. They, for example, assist transport planners in prioritizing equipment security efforts and resource allocation to the areas of greatest risk, and help to prepare contingency plans based on drivers’ behavioral response.     

Modality pairing effects and the response selection bottleneck

The present experiment examined the effects of input/output modality pairings on dual-task performance using the psychological refractory period (PRP) procedure. Four groups of participants performed two tasks composed of the same sets of inputs (visual and auditory) and the same sets of outputs (manual and vocal), but with different input/output modality pairings. Whereas modality pairings had only small effects on single-task reaction times, they had large effects on dual-task reaction times. The modality pairing effect cannot stem from differences in the difficulty of stimulus classification or response execution, because these task demands were the same across groups. The effect also does not appear to result from changes in stimulus-response compatibility. The present findings suggest dual-task interference arises not only from postponement of central operations (due to a central bottleneck), but also from a slowing of central operations whose magnitude is sensitive to the input/output modality pairings.     

Visual working memory for trained and novel polygons

This study investigates whether training changes the capacity of visual working memory (VWM). We compared change detection performance for novel and trained polygons. During training, subjects developed familiarity with 8 random polygons. Specifically, 4 polygons from a set of 8 were presented on each trial. After a brief retention interval, one of the polygons changed and subjects judged which one had changed (Exps. 1–2) or whether there was a change (Exp. 3). After 320 training trials, subjects could recognize the trained polygons with high accuracy. In the testing phase, subjects carried out the same task again, only this time each trial might contain all familiar polygons, all novel polygons, or a mixture of familiar and novel polygons. We found that change detection performance improved during training, but the improvement was not limited to trained polygons. We suggest that familiarity of non-nameable shapes plays a limited role in modulating the capacity of VWM.     

Cross-generational acceptance of and interest in advanced vehicle technologies: A nationwide survey

The number of older drivers on the roadways is increasing; at the same time, technology in the automotive environment is rapidly evolving. To investigate the potential impact of these converging changes, this study used a cross-generational approach to compare driver attitudes toward advanced automotive technologies. Approximately 1000 drivers between the ages of 18 and 85 located across the United States responded to a survey about their opinions regarding general technology, advanced in-vehicle technology, and near-horizon connected vehicle systems. Participant responses were categorized using a generational construct, sorting responses not only by age but by shared life experiences (e.g. economic circumstances, involvement in wartime activities, cultural movements, etc.). The oldest generation (the “Silent” generation) exhibited the least interest in and comfort with advanced technology, although they owned and used advanced in-vehicle technology at approximately the same rates as the two middle generations. The youngest generation (the “Millennial” generation) was most likely to be interested in and comfortable with technology, but was least likely to own vehicles with advanced technology. All participants expressed interest in safety-related connected vehicle systems, but less so in infotainment applications. Reservations regarding data security and system cost were shared across generations. These findings are framed in the context of an aging population with unique driving and vehicle needs, and provide information that may assist both with vehicle technology design aspects and the proposed large-scale implementation of connected vehicle systems, including considerations for seniors and emphasis on safety systems and data security.     

On the optimality of serial and parallel processing in the psychological refractory period paradigm: Effects of the distribution of stimulus onset asynchronies

Within the context of the psychological refractory period (PRP) paradigm, we developed a general theoretical framework for deciding when it is more efficient to process two tasks in serial and when it is more efficient to process them in parallel. This analysis suggests that a serial mode is more efficient than a parallel mode under a wide variety of conditions and thereby suggests that ubiquitous evidence of serial processing in PRP tasks could result from performance optimization rather than from a structural bottleneck. The analysis further suggests that the experimenter-selected distribution of stimulus onset asynchronies (SOAs) influences the relative efficiency of the serial and parallel modes, with a preponderance of short SOAs favoring a parallel mode. Experiments varying the distribution of SOAs were conducted, and the results suggest that there is a shift from a more serial mode to a more parallel mode as the likelihood of short SOAs increases.     

Dual-task processing in younger and older adults: similarities and differences revealed by fMRI

fMRI was used to explore age differences in the neural substrate of dual-task processing. Brain activations when there was a 100 ms SOA between tasks, and task overlap was high, were contrasted with activations when there was a 1000 ms SOA, and first task processing was largely complete before the second task began. Younger adults (M=21 yrs) showed activation in dorsolateral prefrontal cortex and in parietal areas as well as in ventral medial frontal cortex and sub-lobar areas. Activations in older adults (M=71 yrs) did not differ significantly from younger adults except for higher activations in occipital and polar prefrontal cortex. The results were well fit by a model with two networks managing dual-task interference, a medial prefrontal network that detects changes in the stimulus situation and maps them to associated changes in the valence of response mappings and a lateral frontal-parietal network that initiates and carries out the shift from one task to the other. The additional activations in older adults as a group and the correlations of individual differences in activation with performance were consistent with recruitment within each of these networks. Alternative explanations such as hemispheric asymmetry reduction and reactive rather than proactive processing in older adults were not supported.     

Selective impairment of masked priming in dual-task performance

This study investigated the impact of divided attention on masked priming. In a dual-task setting, two tasks had to be carried out in close temporal succession: a tone discrimination task and a masked priming task. The order of the tasks was varied between experiments, and attention was always allocated to the first task—that is, the first task was prioritized. The priming task was the second (nonprioritized) task in Experiment 1 and the first (prioritized) task in Experiment 2. In both experiments, “novel” prime stimuli associated with semantic processing were essentially ineffective. However, there was intact priming by another type of prime stimuli associated with response priming. Experiment 3 showed that all these prime stimuli can reveal significant priming effects during a task-switching paradigm in which both tasks were performed consecutively. We conclude that dual-task specific interference processes (e.g., the simultaneous coordination of multiple stimulus–response rules) selectively impair priming that is assumed to rely on semantic processing.     

Psychological refractory period in introverts and extraverts

The present study was designed to explore extraversion-related differences in the psychological refractory period (PRP). PRP refers to a bottleneck of information processing that becomes evident when participants are required to respond to two signals (S1 and S2) presented in rapid succession. If this capacity limit of premotor information processing is essential for differences in speed of information processing between introverts and extraverts, magnitude of the PRP effect should vary as a function of extraversion. Due to the failure of previous attempts to establish extraversion-related differences in the PRP effect, we also obtained lateralized readiness potentials (LRPs). For this purpose, 63 introverted and 63 extraverted female participants were tested with a standard PRP design. Extraverts responded faster to S2 and exhibited shorter stimulus-locked LRP latencies compared to introverts. Although a general PRP effect could be shown at the behavioral and psychophysiological level, there was no indication for any extraversion-related differences in PRP. Thus, extraversion-related differences in speed of information processing at the premotor level appear unlikely to originate from individual differences in the capacity limits underlying the PRP phenomenon. Furthermore, our findings provide converging evidence for the notion that extraversion-related individual differences in processing speed depend on specific task demands.     

Introspective reports of reaction times in dual-tasks reflect experienced difficulty rather than timing of cognitive processes

Reports of introspective reaction times (iRTs) have been used to investigate conscious awareness during dual-task situations. Previous studies showed that dual-task costs in RTs (the psychological refractory period, PRP, effect) are not reflected in participants’ introspective reports. This finding has been attributed to conscious awareness of Task 2 being delayed while Task 1 is centrally processed. Here, we test this Temporal model and compare it to an alternative that assumes participants base their iRTs on experienced difficulty. We collected iRTs and difficulty estimates after each trial of a PRP paradigm in which the perceptual difficulty of either Task 2 (Experiment 1) or Task 1 (Experiment 2) was manipulated. Our results largely support the difficulty-based account, suggesting that in a dual-task situation, iRTs do not reflect timing of cognitive processes but are strongly influenced by the experience of difficulty.     

Concurrent deployment of visual attention and response selection bottleneck in a dual-task: Electrophysiological and behavioural evidence

Visual attention and response selection are limited in capacity. Here, we investigated whether visual attention requires the same bottleneck mechanism as response selection in a dual-task of the psychological refractory period (PRP) paradigm. The dual-task consisted of an auditory two-choice discrimination Task 1 and a conjunction search Task 2, which were presented at variable temporal intervals (stimulus onset asynchrony, SOA). In conjunction search, visual attention is required to select items and to bind their features resulting in a serial search process around the items in the search display (i.e., set size). We measured the reaction time of the visual search task (RT2) and the N2pc, an event-related potential (ERP), which reflects lateralized visual attention processes. If the response selection processes in Task 1 influence the visual attention processes in Task 2, N2pc latency and amplitude would be delayed and attenuated at short SOA compared to long SOA. The results, however, showed that latency and amplitude were independent of SOA, indicating that visual attention was concurrently deployed to response selection. Moreover, the RT2 analysis revealed an underadditive interaction of SOA and set size. We concluded that visual attention does not require the same bottleneck mechanism as response selection in dual-tasks.     

Speaking up in ad hoc multiteam systems: Individual-level effects of psychological safety,status, and leadership within and across teams

Speaking up in high-risk organizations plays a pivotal role in the mitigation of errors and can make the difference between life and death. To date, speaking up has been studied mostly within teams. However, many high-risk organizations rely on the effective collaboration across teams in ad hoc multiteam systems (MTS). This study widens the scope of research from teams to MTS and empirically compares the mechanisms involved in speaking up within versus across teams in ad hoc MTS-aircrews. In a sample of 1490 aircrew members of a European airline, we found that crewmembers’ individual level perceptions of psychological safety mediated both the relationship between status and speaking up and between perceived leader inclusiveness and speaking up within teams. Across teams, however, psychological safety and leader inclusiveness—as perceived by pursers in their role as boundary spanners—showed no effect. Instead, it was pursers’ within-team perceptions of psychological safety that mediated between status and speaking up across teams. Teams in ad hoc MTS may thus serve as safe harbours supporting their members also in interactions across team boundaries. Implications of findings for research on MTS and practical recommendations to improve speaking up within and across teams in ad hoc MTS are discussed.     

Lottery attractiveness and presentation mode of probability and value information

The attractiveness of lotteries that vary in p (probability) and o (outcome) depends on the presentation mode of p and o information. Extending previous findings on temporally experienced p, we manipulate the numerically stated versus spatially experienced format of both p (graphical presentation of a distribution of lottery tickets in an urn) and o (distribution of money notes). Lottery attractiveness ratings were sensitive to the expected value (EV), but p received more weight than o at constant EV levels (p‐dominance). Both EV sensitivity and p‐dominance were enhanced for experienced p and numerical o. This format particularly revealed the unattractiveness of low‐p lotteries. Experiencing p was functional in terms of accuracy and high‐risk avoidance, but only when the task environments rendered p diagnostic of EV. The presentation mode manipulations did not affect the initial perception stage but the relative weighting of p and o in the final judgment integration stage. Copyright © 2010 John Wiley & Sons, Ltd.     

Sensory modality and method of item information presentation in memory

Investigated were differences in paired-associate learning for auditory versus visual modalities and within each modality the anticipation and study test methods of item presentation were compared. Extant reports re these two sensory modalities and of the two learning methods had been inconsistent. In this study of 40 university students, the learning of CVC-CVC nonsense syllable pairs was significantly better with the visual than with the auditory modality. The study-test method was significantly superior to the anticipation method in the visual mode. With auditory presentations, however, acquisition levels for both methods were the same. Significant interactions were observed between sensory modalities and methods of presentation. At present the retention interval theory (Izawa 1972–1979b) appears to account best for the varied findings with respect to the two methods of presentation.     

注意力资源限制与双任务的相互干扰机制

采用心理不应期研究范式, 两个反应时实验检测了注意力资源分配的特征以及双任务的相互干扰机制。每次实验中, 要求被试快速、相继对高低音辨别任务(T1)和Stroop任务(T2)作出选择性反应, T1和T2间采用6种不同的时间间隔(SOA), 以系统考察不同SOA条件下两个任务的反应时走势。结果发现：(1) 在重叠的双任务情境中, T1的中枢加工导致在T2上出现显著的PRP效应, T2的中枢反应选择对T1的反应选择和反应执行加工同样产生显著的影响。SOA以及T2的难度与复杂度实质性地影响了T1的反应选择和反应执行加工。(2) 当两个任务同时需要进行中枢反应选择加工时, 一个任务占用更多的注意资源将导致另一任务获得较少的注意资源, 注意资源量的多寡直接决定了该任务的加工效率。(3) 两个任务的加工相互影响、相互制约, 这种制约机制不仅仅存在于中枢反应选择阶段, 在反应执行阶段仍然存在。     

Effects of information presentation mode and learning paradigm on the learning of probabilistic inference tasks under different levels of memory strain

The effects of information presentation mode (i.e. visual access vs. not access to an ordered array of cue combinations) and learning paradigm (i.e. selection vs. reception of cue-combinations) on learning of two-cue probabilistic inference tasks were studied in two 2 × 2 factorial experiments representing two levels of memory strain. The results showed that information presentation mode affected performance regardless of amount of memory strain, while learning paradigm affected performance only under conditions of high memory strain.     

Processing spatial-temporal information in recent-onset schizophrenia: the study of short-term memory and its susceptibility to distraction

Memory impairment is a core feature in schizophrenia (SZ). The aim of this study was to investigate short-term memory (STM) and its sensitivity to distraction with visual-spatial material. This study comprised 23 recent-onset SZ patients and 23 healthy controls. The degree of disruption upon recall from interleaving irrelevant items within a sequence of to-be-remembered items-the sandwich effect [Hitch, G. J. (1975). The role of attention in visual and auditory suffix effects. Memory and Cognition, 3, 501-505]-was examined. STM performance, whether in the presence or absence of distraction, was poorer and markedly more vulnerable to disruption in SZ. Our results suggest that processing spatial information in STM is susceptible to interference in SZ.     

Evaluating the impact of adaptive signal control technology on driver stress and behavior using real-world experimental data

While the operational and crash reduction benefits of adaptive signal control technology (ASCT) have long been investigated, the impact of this technology on driver behavior and stress is still uncertain. This study evaluated the impact of ASCT on driver behavior and stress in a real-world environment. Participants travelled through two arterial corridors, one equipped with ASCT and the other having traditional time-of-day coordinated signals. Driver stress was measured using a heart rate detector and a perceived stress scale while driver behavior was examined using vehicular trajectory data. Overall, driving behavior improved on the ASCT as compared to the non-ASCT corridor, as indicated by higher speeds and a fewer number of stops on the ASCT corridor relative to the non-ASCT corridor. Repeated measures ANOVA showed a statistically significant reduction in driver heart rate by −10 beats per minute over the ASCT corridor. A similar trend was observed for drivers’ perceived stress, analyzed by Wilcoxon sign ranked test. Driving behavior also showed significant improvement with ASCT presence, and speed was found to be negatively correlated with stress. Furthermore, the participants’ speed was controlled by the two systems i.e. ASCT and non-ASCT as expected. This study provides a significant proof of concept that ASCT can create positive improvements in driver stress and behavior that can be further investigated in the future.     

Responding maintained under fixed-interval and fixed-time schedules of electric shock presentation

Following initial histories under a schedule of electric shock postponement, lever pressing in squirrel monkeys was maintained under fixed-interval and fixed-time schedules of electric shock presentation. No difference in either rate or pattern of responding was obtained when these schedules were presented as components of a multiple schedule. When they were presented singly for long periods of time, the fixed-interval schedule consistently maintained a higher response rate than the fixed-time schedule. The pattern of responding under both schedules was similar, typically consisting of a pause at the beginning of each interval followed by either a steady or a positively accelerating rate of responding. The results suggest that the response-shock dependency is of critical importance in the maintenance of high rates of responding under schedules of electric shock presentation, and support the general view that such responding may be conceptualized as operant behavior under control of many of the same variables that control responding under comparable schedules of food or water reinforcement.