Racial Differences in Time at Work Not Working

Racial differences in effort at work, if they exist, can potentially explain race-based wage/earnings disparities in the labor market. The authors estimate specifications of time spent on non-work activities at work by Black and White males and females with data from the American Time Use Survey. Estimates reveal that trivially small differences occur between non-Hispanic Black and non-Hispanic White males in time spent not working while on the job that disappear entirely when correcting for non-response errors. The findings imply that Black–White male differences in the fraction of the workday spent not working are either not large enough to partially explain the Black–White wage gap, or simply do not exist at all.

Now you see it, now you don’t: dynamism amplifies the typicality effect

Some safety events do not stabilise in a coherent state, presenting with transient or intermittent features. Such dynamism may pose problems for human performance, especially if combined with non-typical stimuli that are rarely encountered in everyday work. This may explain undesirable pilot behaviour and could be an important cognitive factor in recent aircraft accidents. Sixty-five airline pilots tested a real-world typicality gradient, composed of two cockpit events, a typical event, and a non-typical event, across two different forms of dynamism, a stable, single system transition, and an unstable, intermittent system transition. We found that non-typical event stimuli elicited a greater number of response errors and incurred an increased response latency when compared to typical event stimuli, replicating the typicality effect. These performance deteriorations were amplified when a form of unstable system dynamism was introduced. Typical stimuli were unaffected by dynamism. This indicates that dynamic, non-typical events are problematic for pilots and may lead to poor event recognition and response. Typical is advantageous, even if dynamic. Manufacturers and airlines should evolve pilot training and crew procedures to take account of variety in event dynamics.

Error Analysis of the Combined-Scan High-Speed Atomic Force Microscopy

A combined tip-sample scanning architecture can improve the imaging speed of atomic force microscopy (AFM). However, the nonorthogonality between the three scanners and the nonideal response of each scanner cause measurement errors. In this article, the authors systematically analyze the influence of the installation and response errors of the combined scanning architecture. The experimental results show that when the probe in the homemade high-speed AFM moves with the Z-scanner, the spot position on the four-quadrant detector changes, thus introducing measurement error. Comparing the experimental results with the numerical and theoretical results shows that the undesired motion of the Z-scanner introduces a large error. The authors believe that this significant error occurs because the piezoelectric actuator not only stretches along the polarization direction but also swings under nonuniform multifield coupling. This article proposes a direction for further optimizing the instrument and provides design ideas for similar high-speed atomic force microscopes.

Who do phone surveys miss, and how to reduce exclusion: recommendations from phone surveys in nine Indian states

Computer-assisted telephone interviews (CATI) through mobile phones are a low-cost, rapid and safe way to collect data. However, decisions for how such mobile phone surveys are designed and implemented, and their data analysed, can have implications for the sample reached, and in turn affect the generalisability of sample estimates. In this practice paper, we propose a framework for extending the use of CATI–mobile phone surveys in India, which can be applied broadly to future surveys conducted using this method. Across the stages of design, implementation and analysis, we outline challenges in ensuring that the data collected through such surveys are representative and provide recommendations for reducing non-coverage and non-response errors, thereby enabling practitioners in India to use CATI–mobile phone surveys to estimate population statistics with lower bias. We support our analysis by drawing on primary data that we collected in five mobile phone surveys across nine Indian states in 2020. Our recommendations can help practitioners in India improve the representativeness of data collected through mobile phone surveys and generate more accurate estimates.

Non-Proportionality Indices and Error Constraint in Modal Analysis of Viscously Damped Linear Structures

Use of modal procedures in systems with non-proportional damping (such as structures with added viscous damping systems) results in response errors, shown in this study to depend on dissimilar and often conflicting conditions for different variables and stories; thus, it is not possible to propose simple rules based on structural or damping properties to limit the error in a global way. However, four existing indices (originally proposed to measure damping non-proportionality) present a positive correlation with the extreme errors in modal procedures for all variables and stories. Thus, limiting the index value is a sufficient condition to keep the error in all variables within a given threshold. For practical application, limit values for these indices are tabulated as a function of error and can be used as an acceptance criterion for the validity of modal procedures.

Awareness is required for autonomic performance monitoring in instrumental learning: Evidence from cardiac activity

Performance monitoring is a vital aspect of successful learning and decision-making. Performance errors are reflected in the autonomic nervous system, indicating the need for behavioural adjustment. As part of this response, errors cause a pronounced deceleration in heart rate, compared to correct decisions, and precede explicit awareness of the stimulus-outcome contingencies. However, it is unknown whether those signals are present and able to inform instrumental learning without conscious awareness of the stimuli, where explicit performance monitoring is disabled. With mixed evidence for unconscious instrumental learning, determining the presence or absence of autonomic performance monitoring can shed light on its feasibility.Here, we employed an unconscious instrumental conditioning task, where successful learning is evidenced by increased approach responses to visually masked rewarding stimuli, and avoidance of punishing stimuli. An electrocardiogram (ECG) assessed continuous cardiac activity throughout the learning process. Natural fluctuations of awareness under masking permitted us to contrast learning and cardiac deceleration for trials with, versus without, conscious stimulus awareness. Our results demonstrate that on trials where participants did not consciously perceive the stimulus, there was no differentiation in cardiac response between rewarding and punishing feedback, indicating absence of performance monitoring. In contrast, consciously perceived stimuli elicited the expected deceleration upon error commission. This result suggests that, in unconscious instrumental learning, the brain cannot acquire implicit knowledge of stimulus values, rendering correct instrumental choices impossible. This evidence provides support for the notion that consciousness might be required for flexible adaptive behaviour, and that this may be mediated through bodily signals.

Eye Movement Indices of Post-Saccadic Task Under Cognitive Load: A Path Analysis to Predict Individual’s Performance

Purpose: The evidence on the linear relationship between cognitive load, saccade, fixation, and task performance was uncertain. We tested pathway models for degraded task performance resulting from changes in saccadic and post-saccadic fixation under cognitive load. Methods: Participants' (n = 38) eye movements were recorded using a post-saccadic discrimination task without and with arithmetic operations to impose cognitive load, validated through recording heart rate variability and subjective measurement. Results: Results showed that cognitive load led to longer latencies of saccade and fixation; more inaccurate responses and fewer secondary saccades (P<0.001). Longer saccade latencies influenced task performance indirectly via increases in fixation latency, thereby, longer reaction times and higher response errors were observed due to limited fixation duration on desired target. Conclusion: We suggest that latency and duration of fixation indicate efficiency of information processing and can predict the speed and accuracy of task performance under cognitive load.

To See, Not to See, or to See Poorly: Perceptual Quality and Guess Rate as a Function of Electroencephalography (EEG) Brain Activity in an Orientation Perception Task

Brain oscillations are known to modulate detection of visual stimuli, but it is unclear if this is due to increased guess rate or decreased precision of the mental representation. Here we estimated quality and guess rate as a function of electroencephalography (EEG) brain activity using an orientation perception task. Errors on each trial were quantified as the difference between the target orientation and the orientation reported by participants with a response stimulus. Response errors were fitted to standard mixed model by Zhang and Luck (2008) to quantify how participants’ guess rate and standard deviation parameters varied as a function of brain activity. Twenty-four participants were included in the analysis.Within subjects, the power and phase of delta and theta post-target oscillatory activity were found to vary along with performance on the orientation perception task in that greater power and phase coherence in the 2-5 Hz band range was measured in trials with more accurate responses. In addition, the phase of delta and theta correlated with the degree of response error while oscillatory power did not have a relationship with trial-by-trial response errors. Analysis of task-related alpha activity yielded no significant results implying that alpha oscillations do not play an important role in orientation perception at single trial level. Across participants, only the standard deviation parameter correlated with oscillatory power in the high alpha and low beta frequency ranges. These results indicate that post-target power is associated with the precision of mental representations rather than the guess rate, both across trials within subjects and across subjects.

Competition between parallel sensorimotor learning systems

Sensorimotor adaptation benefits from learning in two parallel systems: one that has access to explicit knowledge, and another that relies on implicit, unconscious correction. However, it is unclear how these systems interact: does enhancing one system’s contributions, for example through instruction, impair the other, or do they learn independently? Here we illustrate that certain contexts can lead to competition between implicit and explicit learning. In some cases, each system is responsive to a task-related visual error. This shared error appears to create competition between these systems, such that when the explicit system increases its response, errors are siphoned away from the implicit system, thus reducing its learning. This model suggests that explicit strategy can mask changes in implicit error sensitivity related to savings and interference. Other contexts suggest that the implicit system can respond to multiple error sources. When these error sources conflict, a second type of competition occurs. Thus, the data show that during sensorimotor adaptation, behavior is shaped by competition between parallel learning systems.