Pupillary correlates of individual differences in n-back task performance.

We used pupillometry during a 2-back task to examine individual differences in the intensity and consistency of attention and their relative role in a working memory task. We used sensitivity, or the ability to distinguish targets (2-back matches) and nontargets, as the measure of task performance; task-evoked pupillary responses (TEPRs) as the measure of attentional intensity; and intraindividual pretrial pupil variability as the measure of attentional consistency. TEPRs were greater on target trials compared with nontarget trials, although there was no difference in TEPR magnitude when participants answered correctly or incorrectly to targets. Importantly, this effect interacted with performance: high performers showed a greater separation in their TEPRs between targets and nontargets, whereas there was little difference for low performers. Further, in regression analysis, larger TEPRs on target trials predicted better performance, whereas larger TEPRs on nontarget trials predicted worse performance. Sensitivity positively correlated with average pretrial pupil diameter and negatively correlated with intraindividual variability in pretrial pupil diameter. Overall, we found evidence that both attentional intensity (TEPRs) and consistency (pretrial pupil variation) predict performance on an n-back working memory task.

Effects of goal-setting on sustained attention and attention lapses.

In three experiments, we examined the effects of goal-setting on sustained attention and attention lapses. We measured both behavioral task performance and subjective attentional states during a four -choice reaction time task (Experiments 1 and 2 administered online; Experiment 3 conducted in-person). Experiment 1 compared a vague goal versus a specific goal. The specific goal reduced lapses in the form of long response times (RTs) but did not impact task-unrelated thoughts. Experiment 2 expanded on E1 by making the specific goal progressively harder. Behavioral lapses (i.e., long RTs) were reduced in the harder-over-time goal condition compared to the control condition. Additionally, while RTs increased with time-on-task in the control condition, RTs in the harder-over-time goal condition remained stable with time-on-task. Experiment 3 aimed to replicate the results of E2 in-person and adjusted the difficulty of the harder-over-time goals to be slightly harder. The results largely replicated E2. Overall, setting specific and difficult task goals led to a reduction in lapses of attention and increased sustained attention performance.

Task sequencing does not systematically affect the factor structure of cognitive abilities.

Latent variable analyses of cognitive abilities are among the major means by which cognitive psychologists test theories regarding the structure of human cognition. Models are fit to observed variance-covariance structures, and the fit of those models are compared to assess the merits of competing theories. However, an often unconsidered and potentially important methodological issue is the precise sequence in which tasks are delivered to participants. Here we empirically tested whether differences in task sequences systematically affect the observed factor structure. A large sample (N = 587) completed a battery of 12 cognitive tasks measuring four constructs: working memory, long-term memory, attention control, and fluid intelligence. Participants were assigned to complete the assessment in one of three sequences: fixed and grouped by construct vs. fixed and interleaved across constructs vs. random by participant. We generated and tested two hypotheses: grouping task sequences by construct (i.e., administering clusters of tasks measuring a cognitive construct consecutively) would (1) systematically increase factor loadings and (2) systematically decrease interfactor correlations. Neither hypothesis was supported. The measurement models were largely invariant across the three conditions, suggesting that latent variable analyses are robust to such subtle methodological differences as task sequencing.

Competition and reward structures nearly eliminate time-on-task performance decrements: Implications for theories of vigilance and mental effort.

Across four experiments, we manipulated features of a simple reaction time (RT) task to examine the effects of such features on sustained attention. In Experiment 1, we created simple RT "game" that pitted participants against two computerized avatars. In one condition, participants were awarded points, while the other condition did not receive points. Performance in the two conditions did not differ, but both conditions showed shorter RTs and shallower time-on-task performance decrements compared to a standard psychomotor vigilance task. In Experiment 2, we removed the competitive feature but retained the point system. In this case, participants without a point system showed a steeper performance decrement than those with a point system. Experiments 3 and 4 replicated these effects and corroborated their findings with pupillometry. Participants in both conditions of Experiment 3 (competitive task) and the points condition of Experiment 4 showed larger task-evoked pupillary responses than participants in the no-points condition of Experiment 4. These findings challenge the notion that time-on-task performance decrements are caused by resource depletion (Smit et al., 2004) and are better explained by motivational control (Hockey, 2011) or cost-benefit theories (Boksem & Tops, 2008; Kurzban et al., 2013) of mental effort and sustained attention. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Baseline pupil diameter does not correlate with fluid intelligence.

There has been debate regarding the correlation between baseline/resting state measures of pupil diameter and cognitive abilities such as working memory capacity and fluid intelligence. A positive correlation between baseline pupil diameter and cognitive ability has been cited as evidence for a role of the locus coeruleus-norepinephrine (LC-NE) and its functional connection with cortical networks as a reason for individual differences in fluid intelligence (Tsukahara & Engle, Proceedings of the National Academy of Sciences, 118(46), e2110630118, 2021a). Several recent attempts to replicate this correlation have failed. The current studies make another attempt and find substantial evidence against a positive correlation between pupil diameter and intelligence. Given the data from the current studies in combination with other recent failures to replicate, we conclude that individual differences in baseline pupil diameter should not be used as evidence for a role of the LC-NE system in goal-directed cognitive activity.

Testing locus coeruleus-norepinephrine accounts of working memory, attention control, and fluid intelligence.

The current set of studies examined the relationship among working memory capacity, attention control, fluid intelligence, and pupillary correlates of tonic arousal regulation and phasic responsiveness in a combined sample of more than 1,000 participants in two different age ranges (young adults and adolescents). Each study was designed to test predictions made by two recent theories regarding the role of the locus coeruleus-norepinephrine (LC-NE) system in determining individual differences in cognitive ability. The first theory, proposed by Unsworth and Robison (2017a), posits two important individual differences: the moment-to-moment regulation of tonic arousal, and the phasic responsiveness of the system to goal-relevant stimuli. The second theory, proposed by Tsukahara and Engle (2021a), argues that people with higher cognitive abilities have greater functional connectivity between the LC-NE system and cortical networks at rest. These two theories are not mutually exclusive, but they make different predictions. Overall, we found no evidence consistent with a resting-state theory. However, phasic responsiveness was consistently correlated with working memory capacity, attention control, and fluid intelligence, supporting a prediction made by Unsworth and Robison (2017a). Tonic arousal regulation was not correlated with working memory or fluid intelligence and was inconsistently correlated with attention control, which offers only partial support for Unsworth and Robison's (2017a) second prediction.

Oculometric indicators of individual differences in preparatory control during the antisaccade task.

Individual differences in preparatory control in the antisaccade task were examined in two experiments via an examination of pupillary responses and fixation stability during the preparatory delay. In both experiments, high attention control individuals (high-antisaccade performers) demonstrated larger pupillary responses during the preparatory delay than low attention control individuals (low-antisaccade performers). These results suggest that variation in antisaccade performance were partially due to individual differences in the ability to ramp up and regulate the intensity of attention allocated to preparatory control processes. Additionally, fixation stability, working memory capacity, susceptibility to off-task thinking, and task-specific motivation were found to correlate with antisaccade performance. Furthermore, both preparatory control and off-task thinking accounted for much of the relation between working memory capacity and antisaccade. These results provide evidence that individual differences in antisaccade performance are multifaceted and that variation in preparatory control (along with other factors) are critically important. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Abrupt vs. gradual visual onsets in go/no-go sustained attention tasks.

Two experiments compared both average performance and changes in performance across time in abrupt- and gradual-onset sustained attention tasks. Experiment 1 compared abrupt- and gradual-onset digits. In conditions where the digits onset and offset abruptly and appeared only briefly, similar to typical conditions in the Sustained Attention to Response Task (SART), participants committed more errors on no-go trials and responded faster overall, indicative of a shift in the speed/accuracy tradeoff toward speed. When the digits abruptly onset but remained on-screen for a longer period of time, there were no differences in no-go error rates, hit rates, or reaction time (RT) variability, but participants still emitted faster RTs overall. Experiment 2 compared abrupt- and gradual-onset images. Similar to Experiment 1, abrupt-onset, short-duration images induced more no-go errors and faster RTs, but also more RT variability and reduced hit rates. In the abrupt-onset, long-duration condition, again the only performance difference was a decrease in average RTs. We discuss implications for using these two types of tasks in sustained attention research.

Pupillometry as a Window into Young Children's Sustained Attention.

Sustained attention is critical to cognition, social competence, and academic success. Importantly, sustained attention undergoes significant development over the early childhood period. Yet, how sustained attention fluctuates over time on task has not been clearly outlined, particularly in young children. In this study, we provide a first test of whether the pupillary response can be used as an indicator of moment-to-moment sustained attention over time on task in young children. Children aged 5 to 7 years (N = 41) completed a psychomotor vigilance task, where they were asked to press a button as fast as possible at the onset of a target stimulus. We measured reaction times over the course of the task, pupil size prior to target onset (baseline pupil size), and pupil size in response to target onset (task-evoked pupil size). The results showed a stereotypical vigilance decrement in children's response times: as time on task increased, reaction times increased. Critically, children's task-evoked pupil size decreased over time on task, while no such change was present in baseline pupil size. These results suggest that young children's waning sustained attention may be linked to a decrease in alertness while overall arousal is maintained. We discuss the importance of leveraging pupillometry to understand the mechanisms of sustained attention over individuals and development.

An examination of relations between baseline pupil measures and cognitive abilities.

Examining individual differences in pupil size and pupillary dynamics have revealed important insights into the nature of individual differences in cognitive abilities like working memory capacity, long-term memory, attention control, and fluid intelligence. These findings are often tied to the locus coeruleus-norepinephrine (LC-NE) system, as this system has a tight temporal correlation with pupil diameter. Some recent research has demonstrated positive correlations between resting pupil size and cognitive ability, specifically fluid intelligence. The present study attempted to replicate such relations. Across three studies, a large sample of participants (N = 845) completed batteries of cognitive ability measures and measures of resting pupil size and pupillary hippus (fluctuations in pupil diameter). The cognitive measures comprised tasks previously used to measure attention control, visual short-term memory capacity, fluid intelligence, working memory capacity, and visuospatial ability. At the factor level, cognitive ability and pupil size correlated near zero. We did observe some limited evidence for a negative correlation between resting pupillary hippus and cognitive ability. Given the null findings in the present data, we encourage further replication of relations between resting pupil measures and cognitive abilities before making any strong theoretical conclusions about such relations.

A multimodal analysis of sustained attention in younger and older adults.

Age-related cognitive decline has been attributed to processing speed differences, as well as differences in executive control and response inhibition. However, recent research has shown that healthy older adults have intact, if not superior, sustained attention abilities compared to younger adults. The present study used a combination of reaction time (RT), thought probes, and pupillometry to measure sustained attention in samples of younger and older adults. The RT data revealed that, while slightly slower overall, older adults sustained their attention to the task better than younger adults, and did not show a vigilance decrement. Older adults also reported fewer instances of task-unrelated thoughts and reported feeling more motivated and alert than younger adults, despite finding the task more demanding. Additionally, older adults showed larger, albeit later-peaking, task-evoked pupillary responses (TEPRs), corroborating the behavioral and self-report data. Finally, older adults did not show a shallowing of TEPRs across time, corroborating the finding that their RTs also did not change across time. The present findings are interpreted in light of processing speed theory, resource-depletion theories of vigilance, and recent neurological theories of cognitive aging. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The influence of working memory capacity and lapses of attention for variation in error monitoring.

In two experiments, individual differences in working memory capacity (WMC), lapses of attention, and error monitoring were examined. Participants completed multiple WMC tasks along with a version of the Stroop task. During the Stroop, pupil diameter was continuously monitored. In both experiments, error phasic pupillary responses were larger than phasic pupillary responses associated with correct incongruent and correct congruent trials. WMC and indicators of lapses of attention were correlated with error pupillary response, suggesting that high WMC and low lapse individuals had enhanced error monitoring abilities compared with low WMC and high lapse individuals. Furthermore, in Experiment 2 error awareness abilities were associated with WMC, lapses of attention, and the error phasic pupillary responses. Importantly, individual differences in the susceptibility to lapses of attention largely accounted for the relationship between WMC and error monitoring in both experiments. Collectively, these results suggest that WMC is related to error monitoring abilities, but this association is largely due to individual differences in the ability to consistently maintain task engagement and avoid lapses of attention.

Individual differences in working memory capacity, attention control, fluid intelligence, and pupillary measures of arousal.

The present study examined individual differences in 3 cognitive abilities: attention control (AC), working memory capacity (WMC), and fluid intelligence (gF) as they relate the tendency to experience task-unrelated thoughts (TUTs) and the regulation of arousal. Cognitive abilities were measured with a battery of 9 laboratory tasks, TUTs were measured via thought probes inserted into 2 tasks, and arousal regulation was measured via pupillometry. Recent theorizing (Unsworth & Robison, 2017b) suggests that 1 reason why some people experience relatively frequent TUTs and relatively poor cognitive performance-especially AC and WMC-is that they exhibit dysregulated arousal. Here, we examined how arousal regulation might predict both AC and WMC, but also higher-order cognitive abilities like gF. Further, we examine direct and indirect associations with these abilities via a mediating influence of TUT. Participants who reported more TUTs also tended to exhibit poorer AC, lower WMC, and lower gF. Arousal dysregulation correlated with more TUTs and lower AC. However, there was no direct correlation between arousal regulation and WMC, nor between arousal regulation and gF. The association between arousal regulation and gF was indirect via TUT. We discuss the implications of the results in light of the arousal regulation theory of individual differences and directions for future research. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Pupillary correlates of individual differences in long-term memory.

The present study is the first to examine individual differences in long-term memory, arousal dysregulation, and intensity of attention within the same experiment. Participants (N = 106) completed 28 lists of an immediate free-recall task while their pupil diameter was recorded via an eye-tracker during the encoding period. Two main pupillary measures were extracted: intraindividual variability in pre-list pupil diameter and evoked pupillary responses during item encoding. Variability in pre-list pupil diameter served as a measure of arousal dysregulation, and evoked pupillary responses served as a measure of intensity of attention. Based on prior work, we hypothesized that there would be a positive association between intensity of attention and recall ability, and that there would be a negative association between arousal dysregulation and recall ability. Collectively these two measures accounted for 19% of interindividual variance in recall, with 5% attributable uniquely to intensity of attention and 12% attributable uniquely to arousal regulation. The findings demonstrate that there are sources of individual differences in long-term memory that can be revealed via pupillometry, notably the amount of effort deployed during item encoding and the degree to which people exhibit dysregulated arousal. Both findings are consistent with recent theorizing regarding the role of the locus coeruleus (LC)-norepinephrine (NE) system's role in goal-directed cognition. Specifically, the LC governs both moment-to-moment arousal and NE release to cortical regions subserving cognitive processing. Among people for whom this system operates most optimally, long-term memory retention is superior.

The effect of binaural beat stimulation on sustained attention.

Binaural beats have been used as a way of modifying cognition via auditory stimulation. A recent meta-analysis suggests that binaural beat stimulation can have a positive effect on attention (Garcia-Argibay et al., Psychologische Forschung 83:1124-1136, 2019a, Psychological Research Psychologische Forschung 83:357-372, 2019b), with the sample-weighted average effect size being about .58. This is an intriguing and potentially useful finding, both theoretically and practically. In this study, we focus on sustained attention. We delivered beta-frequency (16 Hz) binaural beat stimulation during a sustained attention task. In "Experiment 1", reaction times were faster under beat stimulation than control stimulation in a between-subjects design. However, the effect was modest in magnitude, and model comparisons using Bayes Factors were indiscriminate between including and excluding the effect from the model. We followed this initial experiment with two concurrently administered follow-up experiments. In "Experiment 2", we added thought probes to measure any changes in task engagement associated with binaural beat stimulation. "Experiment 2" revealed a different effect from "Experiment 1": participants in the binaural beat condition exhibited a shallower vigilance decrement. However, the beat stimulation did not affect the thought probes responses. Combining data across the two experiments indicated rather strong evidence against the hypothesis that beta-frequency binaural beats can augment sustained attention, either via a general speeding of responding or a mitigation of the vigilance decrement. Finally, in "Experiment 3", we investigated whether pupillary measures of arousal and/or task engagement would be affected by binaural beat stimulation. There was no evidence for such effects. Overall, we did not observe any consistent evidence that binaural beat stimulation can augment sustained attention or its subjective and physiological correlates.

Individual Differences in Disqualifying Monitoring Underlie False Recognition of Associative and Conjunction Lures.

The current study leveraged experimental and individual differences methodology to examine whether false memories across different list-learning tasks arise from a common cause. Participants completed multiple false memory (associative and conjunction lure), working memory (operation and reading span), and source monitoring (verbal and picture) tasks. Memory discriminability in the associative and conjunction tasks loaded onto a single (general) factor and were unaffected by warnings provided at encoding. Consistent with previous research, source-monitoring ability fully mediated the relation between working memory and false memories. Moreover, individuals with higher source monitoring-ability were better able to recall contextual information from encoding to correctly reject lures. These results suggest that there are stable individual differences in false remembering across tasks. The commonality across tasks may be due, at least in part, to the ability to effectively use disqualifying monitoring processes.

On the relation between working memory capacity and the antisaccade task.

Eight experiments (N = 2,003) assessed the relation between working memory capacity (WMC) and performance on the antisaccade task. Experiments 1-5 and 7 examined individual differences in aspects of goal management processes occurring during the preparatory delay of the antisaccade task. WMC tended to interact with delay interval suggesting that high WMC individuals better prepared for the upcoming trial by activating the task goal to a higher level than low WMC individuals (although these effects were generally small). Experiments 3a, 4, and 7 further demonstrated that individual differences in the consistency of attention (i.e., lapses of attention) were partially important for the relation between WMC and antisaccade performance. Experiment 5 demonstrated that knowledge of the likelihood of target location increased overall performance, but did not interact with WMC. Experiment 6 manipulated stimulus onset asynchrony and suggested that speed factors are also likely important for the relation between WMC and antisaccade performance. Finally, structural equation models in Experiment 7 suggested that lapses of attention and speed factors partially accounted for the relation between WMC and antisaccade, but WMC still accounted for unique variance in antisaccade. Collectively, the results suggest that multiple factors (goal activation, consistency of attention, and speed factors) contribute to the relation between variation in WMC and performance on the antisaccade task. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

3D CNN to Estimate Reaction Time from Multi-Channel EEG.

The study of human reaction time (RT) is invaluable not only to understand the sensory-motor functions but also to translate brain signals into machine comprehensible commands that can facilitate augmentative and alternative communication using brain-computer interfaces (BCI). Recent developments in sensor technologies, hardware computational capabilities, and neural network models have significantly helped advance biomedical signal processing research. This study is an attempt to utilize state-of-the-art resources to explore the relationship between human behavioral responses during perceptual decision-making and corresponding brain signals in the form of electroencephalograms (EEG). In this paper, a generalized 3D convolutional neural network (CNN) architecture is introduced to estimate RT for a simple visual task using single-trial multi-channel EEG. Earlier comparable studies have also employed a number of machine learning and deep learning-based models, but none of them considered inter-channel relationships while estimating RT. On the contrary, the use of 3D convolutional layers enabled us to consider the spatial relationship among adjacent channels while simultaneously utilizing spectral information from individual channels. Our model can predict RT with a root mean square error of 91.5 ms and a correlation coefficient of 0.83. These results surpass all the previous results attained from different studies.Clinical relevance Novel approaches to decode brain signals can facilitate research on brain-computer interfaces (BCIs), psychology, and neuroscience, enabling people to utilize assistive devices by root-causing psychological or neuromuscular disorders.

Examining the effects of goal-setting, feedback, and incentives on sustained attention.

Across four experiments we examined the effects of goal-setting, feedback, and incentivizing manipulations on sustained attention. In addition to measuring task performance, we measured subjective attentional states and momentary feelings of motivation and alertness. Experiment 1 compared two specific goal conditions-one difficult and one easy-with a standard set of instructions. The specific goal conditions both reduced RTs and attenuated the vigilance decrement but did not impact task engagement (motivation or task-unrelated thoughts). Experiment 2 manipulated both goal-setting and feedback across conditions. The combination of a specific goal and feedback had strong effects on both task performance and task engagement. Additionally, feedback increased task engagement (higher motivation and fewer task-unrelated thoughts) regardless of whether or not it was paired with a specific goal. Experiment 3 examined the effect of pairing goals with a reward. Participants in one reward condition (time-based incentive) reported higher motivation but did not show better task performance. Offering a cash incentive to meet a goal did not have an effect on any dependent variables. Finally, in an effort to examine whether more moderately-difficult goals might lead to optimal performance, Experiment 4 examined a broader range of goals. However, we did not see an effect of a moderately-difficult goal on any of the dependent variables. Although some of the experimental manipulations were effective in mitigating the vigilance decrement, none eliminated it. We discuss the theoretical implications of the results with regard to goal-setting theory and theories of vigilance. (PsycInfo Database Record (c) 2021 APA, all rights reserved).