Mental workload and visual impairment: differences between pupil, blink, and subjective rating

This research has two aims: (a) To study the concurrent validity of three measures of mental workload, NASA TLX rating scale, pupil dilation and blink rate, testing the hypothesis that they will provide convergent results using a single-task, and dissociative results for dual-task; and (b) To analyse their capability to predict visual search impairment. These three measures were analyzed in the same cognitive tasks in single-task and dual-task (cognitive task and visual search) conditions in a within-subjects experiment with twenty-nine participants. Mental workload measures showed concurrent validity under single-task condition, but a complex pattern of results arose in the dual-task condition: it is suggested that NASA TLX would be a subjective addition of the rating of each task; pupil dilation would measure the average arousal underlying the cognitive tasks; and the blink rate would produce opposite effects: whereas mental workload of cognitive tasks would increase blink rate, visual demand would inhibit it. All three measures were good predictors of visual impairment. The soundness of these measures is discussed with regard to the applied field of driving and other activities.     

A meta-analysis of the n-back task while driving and its effects on cognitive workload

This study investigates the effect of the n-back task on cognitive workload while driving. Results of 20 studies with over 800 participants in total show a moderate to high mean effect size. That means the n-back task varies cognitive load while driving in a substantial matter. Further analysis reveals several moderator variables: experiments conducted in a driving simulator showed larger effect sizes than on-road studies. This effect decreases with increasing driving simulator fidelity. Furthermore, the specific driving task assignment moderates the effect: lane change task scenarios result in higher effects than other situations. Regarding the different measurement methods of cognitive workload, subjective questionnaires seem to have very high sensitivity. In contrast, n-back performance measures, detection response task measures, and physiological measurements result in moderate effect sizes, and driving performance measures show reduced sensitivity. Regarding different implementations of the n-back task itself, surprisingly, no moderators are found. Overall, the findings highlight the suitability of the n-back task as a method of inducing cognitive load in transportation research. The moderator analysis gives an overview of different methodological designs and how these designs will affect effect sizes.     

A behaviorally-based measure of manifest needs in work settings

This investigation represents an attempt to develop and validate a research instrument (Manifest Needs Questionnaire) capable of measuring the four needs of achievement, affiliation, autonomy, and dominance using behaviorally-based scales. The instrument is designed to measure such needs with specific reference to work settings and with minimal time requirements for completion. Results of both laboratory and field studies among 640 subjects indicate that the instrument exhibits acceptable levels of convergent, discriminant, and predictive validity, as well as reasonably high test-retest reliability and internal consistency. Results are compared to other, lengthier instruments designed to measure similar needs.     

Measuring drivers’ takeover performance in varying levels of automation: Considering the influence of cognitive secondary task

Mixed control by driver and automated system will remain in use for decades until fully automated driving is perfected. Thus, drivers must be able to accurately regain control of vehicles in a timely manner when the automated system sends a takeover request (TOR) at its limitation. Therefore, determining the factors that affect drivers’ takeover quality at varying levels of automated driving is important. Previous studies have shown that visually distracting secondary tasks impair drivers’ takeover performance and increase the subjective workload. However, the influence of purely cognitive distracting secondary tasks on drivers’ takeover performance and how this influence varies at different levels of automation are still unknown. Hence, a 5 (driving modes) × 3 (cognitive secondary tasks) factorial design with the within-subject factors was adopted for this driving simulator experiment. The sample consisted of 21 participants. The participants’ subjective workloads were recorded by the NASA-Task Load Index (NASA-TLX). Results showed that compared to manual driving conditions, the drivers’ subjective workloads were significantly reduced in both partially and highly automated driving conditions, even with a TOR, confirming the benefit of the automated driving system in terms of reducing the driving workload. Moreover, the drivers exhibited a lower takeover behavior quality at high levels of automation than manual driving in terms of increased reaction time, abnormal performance, standard deviation of lane position, lane departure probability, and reduced minimum of time to collision. However, at the highly automated driving condition, the drivers’ longitudinal driving safety and ability to follow instructions improved when performing a highly cognitive secondary task. This phenomenon possibly occurred because automated driving conditions lead to an underload phenomenon, and the execution of highly cognitive tasks transfers drivers into moderate load, which helps with the drivers’ takeover performance.     

Risk behaviour and mental workload: Multimodal assessment techniques applied to motorbike riding simulation

We present data from an ongoing research project on the cognitive, emotional and neuropsychological basis of risk behaviour. The main aim of the project is to build a model of risk behaviour so that if we know certain cognitive, behavioural and emotional variables, we will be able to predict decisions made in the face of uncertainty and risk, with the final goal of designing programs for evaluating, preventing and controlling risk behaviour. The objective of the present study was to look for individual differences in hazard perception during a static riding simulation and their relationship with mental workload. We used a multidimensional methodology, including behavioural, subjective and physiological data. The behavioural measures were obtained in a static riding simulation during eight hazard situations. We evaluated whether eye activity measures correlated with cognitive workload and different types of risky behaviours. Eye movement parameters were measured using a video-based eye tracking system. We found that risk-prone individuals showed specific patterns of risky behaviours and that peak of saccadic velocity and subjective mental workload indexes were both reliable indicators of risk proneness. Mental workload was higher for participants showing attitudes to risk behaviours probably because of a lack of conscious awareness of specific cues indicating dangerous scenarios.     

The power and sensitivity of four core driver workload measures for benchmarking the distraction potential of new driver vehicle interfaces

This study evaluated the power and sensitivity of several core driver workload measures in order to better understand their use as a component of future driver distraction potential evaluation procedures of the in-vehicle human machine interface (HMI). Driving is a task that requires visual, manual and cognitive resources to perform. Secondary tasks, such as mobile phone use and interaction with in-built navigation, which load onto any of these three processing resources increase driver workload and can lead to impaired driving. Because workload and distraction potential are interrelated, a comprehensive method to assess driver workload that produces valid and predictive results is needed to advance the science of distraction potential evaluation. It is also needed to incorporate into New Car Assessment Program (NCAP) testing regimes. Workload measures of cognitive (DRT [Detection Response Task] Reaction Time), visual (DRT Miss Rate), subjective (NASA-TLX [driver workload questionnaire]), and temporal demand (Task Interaction Time) were collected as participants drove one of 40 vehicles while completing a variety of secondary tasks with varying interaction requirements. Of the evaluated measures, variance and power analyses demonstrated that Task Interaction Time is the most sensitive in detecting differences in driver workload between different in-vehicle HMIs, followed by DRT Miss Rate, NASA-TLX and finally DRT Reaction Time. There were relatively weak correlations between each of the four measures. These results suggest that Task Interaction Time, coupled with a reliable visual demand metric such as DRT Miss Rate, eye glance coding, or visual occlusion, more efficiently detect differences in driver workload between different HMIs compared to DRT Reaction Time and the NASA-TLX questionnaire. These results can be used to improve the understanding of the utility of each of these core driver workload measures in assessing driver distraction potential.     

Tactile detection response task: Metrics for assessing drivers’ cognitive workload

The Tactile Detection Response Task (TDRT) has been used to assess the cognitive workload of driver distraction with response time and miss rate as metrics of cognitive workload. However, it is not clear which metric is more sensitive and whether sensitivity is maintained for visual tasks. The objective of this study was to assess the sensitivity of the TDRT to changes in cognitive workload and to examine whether the sensitivity depends on task modality. A driving simulator study was conducted with 24 participants. The study included restaurant selection tasks with three presentation modalities (auditory, visual, and hybrid) and two difficulty levels (low and high). The high difficulty level was designed to be more cognitively demanding than the low difficulty level. Mixed-effects models were applied to examine the TDRT metrics and task difficulty level. The model controlled for age group, gender, and included a random effect for participants. The high difficulty level of the auditory tasks significantly increased the likelihood of missing a TDRT stimulus. No statistically significant differences were observed for visual and hybrid tasks. TDRT response time was not significantly associated with the difficulty level, regardless of task modality. In this study, the binary outcome TDRT miss was thus considered a more sensitive metric of cognitive workload than TDRT response time. TDRT response time can still be used to measure cognitive workload when tasks are relatively easy and the TDRT miss rate is close to zero. In addition, the sensitivity of the TDRT miss diminished for tasks that involved a visual component. Researchers who use TDRT to measure the cognitive workload associated with visual tasks should be aware of this limitation.     

Le vieillissement cognitif et l’hypothèse de l’exercice mental révisée

Although intuitively plausible, the evidence relevant to the mental exercise hypothesis is currently mixed. One of the main controversial issues concerning the investigation of this hypothesis has to do with how cognitive stimulation is assessed. The mental exercise hypothesis was here tested with a subjective and self-reported measure of cognitive stimulation. Overall, results have supported that a greater engagement in cognitively stimulating activities was associated with higher levels of cognitive functioning. However, the rate of cognitive decline with advancing age was not reduced for people who were more mentally active. Of great interest, the subjective measure of cognitive engagement have supported that cognitive demands assessed by participants on activities varied as a function of participants’ cognitive resources: lower cognitive resources were associated with lower perceived cognitive demands.     

Psychophysiological response to cognitive workload during symmetrical,asymmetrical and dual-task walking

Walking with a lower limb prosthesis comes at a high cognitive workload for amputees, possibly affecting their mobility, safety and independency. A biocooperative prosthesis which is able to reduce the cognitive workload of walking could offer a solution. Therefore, we wanted to investigate whether different levels of cognitive workload can be assessed during symmetrical, asymmetrical and dual-task walking and to identify which parameters are the most sensitive. Twenty-four healthy subjects participated in this study. Cognitive workload was assessed through psychophysiological responses, physical and cognitive performance and subjective ratings. The results showed that breathing frequency and heart rate significantly increased, and heart rate variability significantly decreased with increasing cognitive workload during walking (p < .05). Performance measures (e.g., cadence) only changed under high cognitive workload. As a result, psychophysiological measures are the most sensitive to identify changes in cognitive workload during walking. These parameters reflect the cognitive effort necessary to maintain performance during complex walking and can easily be assessed regardless of the task. This makes them excellent candidates to feed to the control loop of a biocooperative prosthesis in order to detect the cognitive workload. This information can then be used to adapt the robotic assistance to the patient’s cognitive abilities.     

Outcome measures for clinical drug trials in autism

This paper identifies instruments and measures that may be appropriate for randomized clinical trials in participants with autism spectrum disorders (ASDs). The Clinical Global Impressions scale was recommended for all randomized clinical trials. At this point, however, there is no "perfect" choice of outcome measure for core features of autism, although we will discuss five measures of potential utility. Several communication instruments are recommended, based in part on suitability across the age range. In trials where the intention is to alter core features of ASDs, adaptive behavior scales are also worthy of consideration. Several "behavior complexes" common to ASDs are identified, and instruments are recommended for assessment of these. Given the prevalence of cognitive impairment in ASDs, it is important to assess any cognitive effects, although cognitive data from ASD randomized clinical trials, thus far, are minimal. Guidance from trials in related pharmacologic areas and behavioral pharmacology may be helpful. We recommend routine elicitation of side effects, height and weight, vital signs, and (in the case of antipsychotics) extrapyramidal side-effects assessment. It is often appropriate to include laboratory tests and assessments for continence and sleep pattern.     

Effects of cognitive load presence and duration on driver eye movements and event detection performance

This study examined the effects of cognitive load on driving performance for interactions with an in-vehicle information system (IVIS) that varied in duration from 1 to 4 min. Twelve participants drove in a simulator while intermittently performing the IVIS task. There were three IVIS conditions: interacting with the IVIS, non-IVIS periods between IVIS interactions, and baseline driving without the IVIS task. Contrary to our hypothesis, driver response to lead vehicle braking was surprisingly uniform across IVIS conditions. IVIS interaction did undermine driver ability to detect the bicyclist along the side of the road, and some of these performance decrements persisted after the IVIS interaction had ended. Reaction time for bicyclist detection increased from the first to the subsequent minutes of the interaction. Eye movements were influenced by the IVIS conditions but not by task duration. Both ANOVA and factor analyses revealed that some of the changes in eye movements were concurrent with IVIS interaction while others persisted after the driver completed the IVIS interaction. Overall, the findings suggest that two mechanisms might account for the distraction-related performance decrements in this study: competition for processing resources and interference due to activation of competing goals.     

Examining the validity of scores from an instrument designed to measure metacognition of problem solving

The authors' purpose in this study was to gather evidence on the validity of scores on an instrument designed to evaluate levels of metacognition in problem solving--Swanson's 15-item metacognition questionnaire (1990, 1993). Forty-three participants took part in this study: 21 professors and 22 graduate students from several Western and Midwestern campuses in the fields of psychology and educational psychology. A Kendall Coefficient of concordance (W) was performed to determine the consistency of ranked responses for professors, students, and both groups combined, and to determine whether their responses matched those of the scoring key for the instrument we studied. This analysis indicated problems for some of the responses to this instrument, as demonstrated through the ranking task developed in this study. Many of the professors disagreed with the ranking of the responses suggested by Swanson. There is certainly a need for more instruments to validly measure metacognition. This instrument is one that, with some modification, might be used more in research on metacognition.     

Story-based scales: development and validation of questionnaires to measure subjective health status and cultural adherence in British Bangladeshis with diabetes

Questionnaires that measure subjective health status are increasingly used in clinical trials. But scales based on the quantification of subjective traits ("rate your feelings on a scale of 1 to 5") and initially developed in western population samples may not be valid for use in minority ethnic groups, even if accurately translated. The measurement of cultural adaptation and assimilation in immigrant groups is important for health research but has well documented methodological challenges. The aim of this study was to develop valid and reliable questionnaires to measure subjective health status and cultural adherence in a minority ethnic group, using the story as the unit of inquiry. The design was a multi-phase study involving (a) narrative interview, (b) vignette construction, (c) questionnaire development, and (d) questionnaire validation in relation to two scales (well-being and cultural adherence) in British Bangladeshis with diabetes. Using data from in-depth narrative interviews (i.e., a non-directive research technique in which the participant is invited to "tell me the story about your diabetes, starting with when you first noticed anything wrong", and the only prompts used are "tell me more about that" or "what happened next?"; Greenhalgh, Helman, & Chowdhury, 1998; Muller, 1999), we constructed culturally congruent vignettes to depict different subjective health states and behaviours. We refined these items in focus group interviews and validated the instruments on 98 Bangladeshi participants, randomly sampled from GP diabetes registers in inner London and interviewed by a Bangladeshi anthropologist. We used factor analysis to explore the underlying structure in the responses to questionnaire items, plus Cronbach alpha tests to measure internal consistency of scales. The questionnaires were acceptable and credible to Bangladeshi participants with diabetes. Ninety of 98 participants were able and willing to complete them with interviewer assistance. Following factor analysis, we produced two definitive instruments. The well-being scale was a single-factor model with four story-based items (measuring depression, anxiety, physical energy, and social activities), with a Cronbach's alpha of .92. The cultural adherence scale was a single-factor model with five items (measuring religious restrictions, ethnic practices, and social ties), with a Cronbach's alpha of .83. In conclusion, this study has produced two important outputs: (a) easy-to-administer, story-based questionnaires that measure well-being and cultural adherence, which are specific to British Bangladeshis with diabetes; (b) a general method for developing story-based instruments to quantify the subjective experience of illness and adherence to cultural norms, which potentially has applications beyond the study population.     

The effects of driving environment complexity and dual tasking on drivers’ mental workload and eye blink behavior

The goal of the present study was to assess the effectiveness of eye blink behavior in measuring drivers’ mental workload. Previous research has shown that when mental workload increases with the primary task difficulty, blink frequency drops. On the opposite, the number of blinks increases when a cognitive secondary task has to be performed concurrently. However, the combined effects of the primary task difficulty and dual-tasking on blink rate have not been investigated. The present study was thus designed to vary systematically both the primary driving task and the cognitive secondary task demand to examine their combined effects on blink rate. The driving task was manipulated by varying the complexity of a simulated driving environment. The cognitive load was manipulated using a concurrent simple reaction time task or a complex calculation task. The results confirmed that eye blink frequency was a sensitive measure to elicit increased mental workload level coming from the driving environment. They also confirmed that blink rate increased with the introduction of a cognitive secondary task while blink duration was not affected. However, eye blink behavior did not provide a clear mental workload signature when driving task demands and dual-task conditions were varied simultaneously. The overall picture goes against the suitability of eye blink behavior to monitor drivers’ states at least when external and internal demands interact.     

Does it deliver what it promises? Evaluation of cognitive distraction caused by speech-based interfaces with detection response and box task

Speech is considered a promising modality for human-machine interaction while driving, especially in reducing visual and manual distraction. However, speech-based user interfaces themselves have shown to increase cognitive distraction. There remains a lack of standardized and unambiguous methods for measuring the impact of speech-based assistants on cognitive distraction while driving. This work aims to investigate whether the combination of the box task and the detection response task (DRT) is a suitable method for assessing the cognitive distraction caused by speech-based assistants. For this purpose, participants (N = 39) engaged in artificial (n-back tasks) and natural speech-based secondary tasks (interaction with Android’s Google Assistant and Apple's Siri) differing in predefined levels of cognitive workload while performing the box task and the DRT. The results showed that DRT performance differed between the 0-back and 1-back task but not between the different cognitive workload levels of the speech-based assistants. No clear effects emerged for the box task parameters. Thus, the combination of the box task and DRT is well-suited for measuring cognitive distraction caused by artificial secondary tasks but not by natural interactions with speech-based assistants.     

The effect of cognitive testing and feedback on older adults’ subjective age

Subjective age, or how old a person feels, is an important measure of self-perception that is associated with consequential cognitive and health outcomes. Recent research suggests that subjective age is affected by certain situations, including cognitive testing contexts. The current study examined whether cognitive testing and positive performance feedback affect subjective age and subsequent cognitive performance. Older adults took a series of neuropsychological and cognitive tests and subjective age was measured at various time points. Participants also either received positive or no feedback on an initial cognitive task, an analogies task. Results showed that participants felt older over the course of the testing session, particularly after taking a working memory test, relative to baseline. Positive feedback did not significantly mitigate this subjective aging effect. Results suggest that subjective age is malleable and that it can be affected by standard cognitive and neuropsychological test conditions.     

Subjective aspects of cognitive control at different stages of processing

Although research on cognitive control has addressed the effects that different forms of cognitive interference have on behavior and the activities of certain brain regions, until recently, the effects of interference on subjective experience have not been addressed. We demonstrate that, at the level of the individual trial, participants can reliably introspect the subjective aspects (e.g., perceptions of difficulty, competition, and control) of responding in interference paradigms. Similar subjective effects were obtained for both expressed and unexpressed (subvocalized) actions. Few participants discerned the source of these effects. These basic findings illuminate aspects of cognitive control and cognitive effort. In addition, these data have implications for the study of response interference in affect and self-control, and they begin to address theories regarding the function of consciousness.     

Driving in dangerous territory: Complexity and road-characteristics influence attentional demand

Car driving related attentional demands fluctuate according to route complexity and are found to be highly associated with motor-vehicle collisions (MVCs). The purpose of the current study was to explore the inherent attentional demands of scenarios that approximate common crash configurations. Sixty drivers completed a series of 20 simulated driving scenarios incorporating either rear-end or crossing path situations. For each scenario, the complexity of the driving environment was systematically manipulated in terms of vehicle handling and information processing elements. The attentional demands of each scenario were assessed by means of a peripheral detection task (PDT) as well as through a subjective measure of overall difficulty. Our results showed a reduction in PDT performance at intersections where information processing is increased as well as when handling maneuvers behind a lead vehicle were required. The results point to the appropriateness of the PDT as a sensitive measure of cognitive workload. The implications of these findings for future research and safety initiatives are discussed.     

Attentional interference in judgments of musical timbre: individual differences in working memory

Researchers have shown that working memory is related to a variety of high-level cognitive processes. However, the results of recent research have suggested that may be because of its role in attentional control. In the present experiment, the authors investigated that hypothesis by using an attentional interference task with musical stimuli. Listeners were asked to monitor one ear for either a clarinet or violin tone and to ignore any information in the other ear. On some of the trials, they heard only one tone and on other trials, either the same instrument in both ears or different instruments. Individual differences were measured in working memory and musical experience. The results showed more attentional interference in the different-instrument condition for participants with lower working memory scores, which suggested that working memory involves the ability to control attention to inhibit irrelevant information.