Nicholas W. Fraulini

A critical examination of the research and theoretical underpinnings discussed in Thomson, Besner, and Smilek (2016).

Thomson, Besner, and Smilek (2016) propose that performance decrements associated with sustained attention are not consistently the result of a decline in perceptual sensitivity. Thomson et al. (2016) present empirical evidence using a novel, nontraditional vigilance task to support their assumptions. However, in the present rebuttal, we argue that the authors have not only have misinterpreted previous research in sustained attention, but also have misapplied those interpretations to their study. Thomson et al. have also neglected key elements of the literature in their argument, including research on expectancy theory and individual differences on vigilance performance. Furthermore, Thomson and colleagues implement an experimental paradigm that is not appropriate for evaluating sensitivity and bias changes in vigilance tasks. Finally, their analyses do not capture the manner in which changes in response bias and sensitivity can manifest in signal detection theory. We discuss the theoretical and experimental issues contained in Thomson et al. (2016) and propose suggestions for future vigilance research in this area.

Can vigilance tasks be administered online? A replication and discussion.

Recently, experimental studies of vigilance have been deployed using online data collection methods. This data collection strategy is not new to the psychological sciences, but it is relatively new to basic research assessing vigilance performance, as studies in this area of research tend to collect data in the laboratory or in the field. The present study partially replicated the results of a newly developed online vigilance task (Thomson, Besner, & Smilek, 2016). A sample of 130 participants completed the semantic vigilance task created by Thomson et al. (2016) in a research laboratory setting. The present results replicated Thomson et al. (2016) when nonparametric and corrected signal detection measures were used. We suggest that some vigilance tasks typically performed in the laboratory could be administered online. However, we encourage researchers to consider the following factors prior to studying vigilance performance online: (a) the type of vigilance task, (b) the length of the vigilance task, and (c) the signal detection indices most appropriate for their research. It is quite possible that some analyses may yield significant results, whereas other signal detection measures may not (i.e., parametric indices vs. nonparametric indices vs. “corrected” indices) and this point is discussed further in our article.

Sex Differences in the Stress and Workload of Lexical Vigilance

Lexical vigilance requires sustained attention to lexical, verbal, and semantic information over a prolonged period of time. The perceived stress and workload that typically accompany the performance of these tasks remains relatively unknown. Thus, in the present study 213 observers were assigned to either a standard lexical vigilance task or a ‘lure’ vigilance task, which required additional decision-making criteria. The results were analyzed for sex differences between the conditions and across multiple measures of perceived stress and workload. These analyses indicated that women and men perceive the stress and workload associated with lexical vigilance tasks differently. More specifically, women reported greater post-task distress and more temporal demand associated with the task than men. Interestingly, men reported the task being more physically demanding than women. The implications of these results are discussed further.

Sex Differences in Lexical Vigilance Performance

Lexical vigilance is the ability to sustain attention to lexical, semantic, and language-related stimuli, such as words or symbols, for extended periods of time. One gap in the empirical investigation of lexical vigilance is the assessment of sex differences in the performance of these tasks. In the present study, a sample of 213 observers completed a 12-minute lexical vigilance task. Observers were randomly assigned to either a standard task, which required individuals to respond to critical signals and withhold response to neutral events, or a lure task, which required individuals to respond to critical signals while withholding response to neutral events and lures (i.e., stimuli that are categorically similar in nature to critical signals). The results indicated that women and men perform the lure and standard tasks differently depending upon the condition to which they are assigned. Specifically, an inverse relationship was observed between the sexes and conditions in signal detection indices of sensitivity and response bias. We discuss the implications of these results below.

Ceci n’est pas un walrus: lexical processing in vigilance performance

Vigilance, or the ability to sustain attention for extended periods of time, has traditionally been examined using a myriad of symbolic, cognitive, and sensory tasks. However, the current literature indicates a relative lack of empirical investigation on vigilance performance involving lexical processing. To address this gap in the literature, the present study examined the effect of stimulus meaning on vigilance performance (i.e., lure effects). A sample of 126 observers completed a 12-min lexical vigilance task in a research laboratory. Observers were randomly assigned to a standard task (targets and neutral events only) or a lure task (lures, targets, and neutral events presented), wherein lures were stimuli that were categorically similar to target stimuli. A novel analytical approach was utilized to examine the results; the lure groups were divided based on false alarm performance post hoc. Groups were further divided to demonstrate that the presence of lure stimuli significantly affects the decision-making criteria used to assess the performance of lexical vigilance tasks. We also discuss the effect of lure stimuli on measures related to signal detection theory (e.g., sensitivity and response bias).

Examining the Effects of a Novel Training Paradigm for Vigilance on Mental Workload and Stress

Vigilance research often utilizes training to prepare observers for the monotony associated with these types of tasks. Although performance benefits have been shown previously for training, little evidence exists for the subjective effects training for vigilance can impose. The goal of this study is to investigate the effects of two types of training, practice and knowledge of results (KR), on observers’ perceived levels of mental workload and stress. The study makes use of the NASA-TLX and Dundee Stress State Questionnaire (DSSQ) to measure these effects. The results indicate that observers benefit subjectively from both types of training, but in potentially different manners. We discuss the differences in the effects on mental workload and stress, as well as the potential impact on training for vigilance in the future.

A Preliminary Study Examining Novel Training Paradigms for Vigilance

Training for vigilance has been a primary research question for over 70 years. Specifically, researchers have fought to lessen the effects of the vigilance decrement, or the typical decline in performance as time on task increases. In the present study, we examine two forms of training for vigilance: practice and knowledge of result (KR). We propose that providing observers with either practice, KR, or a combination of the two during training will improve performance on a transfer vigil. Our results showed observers receiving practice displayed higher sensitivity and increased conservatism during training, as well as a trend toward higher sensitivity during transfer. These results show the benefits of providing observers practice, which include their performance on a transfer vigil as well as the efficiency of the training itself. We discuss the implications of these findings and how they may impact training for vigilance in the future.

Effects of Social Facilitation on Perceived Workload, Subjective Stress, and Vigilance-Related Anxiety

Vigilance, or sustained attention, refers to the capability of an individual to maintain attention to a stimulus over extended periods of time. Typically, vigilance tasks are associated with high levels of workload and stress, which manifests as less task engagement, and greater distress. Several factors have been shown to affect vigilance and its associated workload and stress (i.e. signal saliency, task difficulty, etc.). However, one factor that has been neglected in previous research on workload, stress, and anxiety is the presence of someone in a supervisory role during the task. Therefore, the purpose of the present investigation was to determine how the presence of a supervisory figure influenced perceived workload, stress, and anxiety that is associated with vigilance tasks. It was hypothesized that the presence of a supervisory figure would decrease workload and distress, and would increase the levels of anxiety, when compared to a non-supervisor.

Performance in Vigilance Tasks is Related to Both State and Contextual Motivation

Vigilance, or sustained attention, is the ability to maintain attention to stimuli over a prolonged period of time. Synonymous with the study of sustained attention is the vigilance decrement, which is a decline in performance as a function of time on task. In the present study, we examined the effects of state motivation (i.e., motivation measured immediately prior to the task) and context-based motivation (i.e., motivation that stems from task instructions) on vigilance performance in a sensory-based vigilance task. Forty-three participants completed a 24-minute vigilance task, as well as measures of stress and workload. The results indicated that those higher in state intrinsic motivation and motivating instructions outperformed their peers in terms of hits and false alarms. We conclude that motivation may help facilitate vigilant attention.

Examining Measures of Mental Workload Across Cognitive- and Sensory-Based Vigilance Tasks

Vigilance refers to the ability of an observer to detect signals over a prolonged period of time. An important component of vigilance is the performance decrement, in which a decline in the correct detection of critical signals occurs as a function of time on task (e.g., Becker, Warm, Dember, & Howe, 1994). Typically, this decline in performance is accompanied by high perceived workload and stress (Warm, Parasuraman, & Matthews, 2008). One problem with traditional measures of mental workload, however, is these measures do not always converge on a single factor of workload. Instead, analyses indicate that workload is most likely multi-faceted (Matthews, Reinerman-Jones, Wohleber, Lin, Mercado, & Abich, 2015). The present research sought to compare two measures of mental workload, the NASA-TLX and Multiple Resource Questionnaire (MRQ), in terms of their respective abilities to measure mental workload in two different types of vigilance tasks (cognitive and sensory). We examined the factor analytic structure of both measures, as well as the intercorrelations of each measure’s scales. We also examined how the validity and reliability of each measure changed based on task type. Exploratory factor analyses (EFA) revealed the factor analytic structure of each mental workload measure to vary depending on task type. The scales of the NASA-TLX combined into one factor for the cognitive task, while the sensory task saw these same scales split between task-related and operator-related sources of workload. EFA for the MRQ scales revealed an emphasis on spatial resources in the sensory condition, whereas the cognitive condition evoked several factors involving the senses (auditory, location, visual). Reliability scores, measured using Cronbach’s α, were high for the MRQ for the cognitive and sensory tasks (α = .840 and α = .866, respectively). Reliability for the NASA-TLX, though, differed markedly for the two tasks, with α = .790 in the cognitive task but α = .439 in the sensory task. Finally, intercorrelations between the two measures showed the cognitive task to bring about both higher intercorrelations within each scale, as well as higher correlations between the scales, than the sensory task. Taken together, our results indicate that the NASA-TLX and MRQ are measuring different constructs depending on the task. Our work extends the results of Matthews et al. (2015) by showing that task parameters should be considered when choosing how to evaluate mental workload. It appears that some measures are reliable only in specific contexts.