Greater weekly physical activity linked to left resting frontal alpha asymmetry in women: A study on gender differences in highly active young adults.

Physical activity, beneficial for physical and psychological health, may facilitate affective mechanisms of positive emotion and approach-motivation. Greater resting frontal alpha asymmetry (FAA), an index of greater relative left than right frontal cortical activity, is a neural correlate of affective mechanisms possibly associated with active lifestyles. This study sought to amplify limited literature on the relationship between physical (in)activity, FAA, and gender differences. College students (n = 70) self-reported physical activity (Total PA) and sedentary activity (Total Sitting) via the International Physical Activity Questionnaire-Short Form (IPAQ-SF), followed by a resting electroencephalography session to record FAA. A Total PA × gender interaction (ß = 0.462, t = 3.163, p = 0.002) identified a positive relationship between Total PA and FAA in women (ß = 0.434, t = 2.221, p = 0.030) and a negative relationship for men (ß = -0.338, t = -2.300, p = 0.025). Total Sitting was positively linked to FAA (ß = 0.288, t = 2.228, p = 0.029; no gender effect). Results suggest affective mechanisms reflected by FAA (e.g., positive emotion, approach-motivation) are associated with physical activity for women, indicating a possible mechanism of the psychological benefits linked with physically active lifestyles. A positive relationship between sedentary behavior and greater left FAA may also reflect motivated mechanisms of behavior that aid in minimizing energy expenditure, particularly within the context of our highly active sample.

Feedback Related Negativity Amplitude is Greatest Following Deceptive Feedback in Autistic Adolescents.

The purpose of this study is to investigate if feedback related negativity (FRN) can capture instantaneous elevated emotional reactivity in autistic adolescents. A measurement of elevated reactivity could allow clinicians to better support autistic individuals without the need for self-reporting or verbal conveyance. The study investigated reactivity in 46 autistic adolescents (ages 12-21 years) completing the Affective Posner Task which utilizes deceptive feedback to elicit distress presented as frustration. The FRN event-related potential (ERP) served as an instantaneous quantitative neural measurement of emotional reactivity. We compared deceptive and distressing feedback to both truthful but distressing feedback and truthful and non-distressing feedback using the FRN, response times in the successive trial, and Emotion Dysregulation Inventory (EDI) reactivity scores. Results revealed that FRN values were most negative to deceptive feedback as compared to truthful non-distressing feedback. Furthermore, distressing feedback led to faster response times in the successive trial on average. Lastly, participants with higher EDI reactivity scores had more negative FRN values for non-distressing truthful feedback compared to participants with lower reactivity scores. The FRN amplitude showed changes based on both frustration and reactivity. The findings of this investigation support using the FRN to better understand emotion regulation processes for autistic adolescents in future work. Furthermore, the change in FRN based on reactivity suggests the possible need to subgroup autistic adolescents based on reactivity and adjust interventions accordingly.

Using Wearable Passive Sensing to Predict Binge Eating in Response to Negative Affect Among Individuals With Transdiagnostic Binge Eating: Protocol for an Observational Study.

BACKGROUND: Binge eating (BE), characterized by eating a large amount of food accompanied by a sense of loss of control over eating, is a public health crisis. Negative affect is a well-established antecedent for BE. The affect regulation model of BE posits that elevated negative affect increases momentary risk for BE, as engaging in BE alleviates negative affect and reinforces the behavior. The eating disorder field's capacity to identify moments of elevated negative affect, and thus BE risk, has exclusively relied on ecological momentary assessment (EMA). EMA involves the completion of surveys in real time on one's smartphone to report behavioral, cognitive, and emotional symptoms throughout the day. Although EMA provides ecologically valid information, EMA surveys are often delivered only 5-6 times per day, involve self-report of affect intensity only, and are unable to assess affect-related physiological arousal. Wearable, psychophysiological sensors that measure markers of affect arousal including heart rate, heart rate variability, and electrodermal activity may augment EMA surveys to improve accurate real-time prediction of BE. These sensors can objectively and continuously measure biomarkers of nervous system arousal that coincide with affect, thus allowing them to measure affective trajectories on a continuous timescale, detect changes in negative affect before the individual is consciously aware of them, and reduce user burden to improve data completeness. However, it is unknown whether sensor features can distinguish between positive and negative affect states, given that physiological arousal may occur during both negative and positive affect states. OBJECTIVE: The aims of this study are (1) to test the hypothesis that sensor features will distinguish positive and negative affect states in individuals with BE with >60% accuracy and (2) test the hypothesis that a machine learning algorithm using sensor data and EMA-reported negative affect to predict the occurrence of BE will predict BE with greater accuracy than an algorithm using EMA-reported negative affect alone. METHODS: This study will recruit 30 individuals with BE who will wear Fitbit Sense 2 wristbands to passively measure heart rate and electrodermal activity and report affect and BE on EMA surveys for 4 weeks. Machine learning algorithms will be developed using sensor data to distinguish instances of high positive and high negative affect (aim 1) and to predict engagement in BE (aim 2). RESULTS: This project will be funded from November 2022 to October 2024. Recruitment efforts will be conducted from January 2023 through March 2024. Data collection is anticipated to be completed in May 2024. CONCLUSIONS: This study is anticipated to provide new insight into the relationship between negative affect and BE by integrating wearable sensor data to measure affective arousal. The findings from this study may set the stage for future development of more effective digital ecological momentary interventions for BE. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/47098.

Peers, play, and performance to build social salience in autistic youth: A multisite randomized clinical trial.

OBJECTIVE: Individuals with autism spectrum disorder (ASD) have significant impairment in social competence and reduced social salience. SENSE Theatre, a peer-mediated, theater-based intervention has demonstrated posttreatment gains in face memory and social communication. The multisite randomized clinical trial compared the Experimental (EXP; SENSE Theatre) to an Active Control Condition (ACC; Tackling Teenage Training, TTT) at pretest, posttest, and follow-up. It was hypothesized that the EXP group would demonstrate greater incidental face memory (IFM) and better social behavior (interaction with novel peers) and social functioning (social engagement in daily life) than the ACC group, and posttest IFM would mediate the treatment effect on follow-up social behavior and functioning. METHOD: Two hundred ninety participants were randomized to EXP (N = 144) or ACC (N = 146). Per protocol sample (≥ 7/10 sessions) resulted in 207 autistic children 10-16 years. Event-related potentials measured IFM. Naive examiners measured social behavior (Vocal Expressiveness, Quality of Rapport, Social Anxiety) and functioning (Social Communication). Structural equation modeling was used to assess treatment effects. RESULTS: SENSE Theatre participants showed significantly better IFM (b = .874, p = .039) at posttest, and significant indirect effects on follow-up Vocal Expressiveness a × b = .064, with 90% CI [.014, .118] and Quality of Rapport a × b = .032, with 90% CI [.002, .087] through posttest IFM. CONCLUSIONS: SENSE Theatre increases social salience as reflected by IFM, which in turn affected Vocal Expressiveness and Quality of Rapport. Results indicate that a neural mechanism supporting social cognition and driven by social salience is engaged by the treatment and has a generalized, indirect effect on clinically meaningful functional outcomes related to core symptoms of autism. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The longest year ever: Emotions and time perception interact to predict how frequently individuals engage in COVID-19 avoidance behaviors.

Affective states alter the perception of how quickly time is passing. However, previous studies have not examined the independent and interactive effects of emotion and time perception on behavioral outcomes. The current study sought to better understand the relationships between affect, time perception, and reported engagement in COVID-19 pathogen avoidance behaviors (e.g., social distancing, wearing a mask) over 1 year. The study sample was comprised of American adults (n = 1,000) recruited using Prolific. The majority of participants in the final sample (50.1% male, 46.8% female, 3.1% nonbinary/other) identified as White/Caucasian (78.9%) or Black/African American (11.9%). The average age in the sample was 34.4 years (SD = 11.3). Consistent with study hypotheses, approach-motivated affective states (happiness) were associated with time flying, and avoidance-motivated affective states (nervous, lack of control) were associated with time dragging. Moderation analyses revealed that reports of greater avoidance-motivated affect and time dragging, and reports of greater approach-motivated affect and time flying interacted to predict more frequent engagement in pathogen avoidance behaviors. These results contribute to the existing literature describing the affective and behavioral effects of the COVID-19 pandemic by suggesting both approach- and avoidance-motivated affective states have important implications for engagement in pathogen avoidance behaviors. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Test-retest reliability of a smartphone-based approach-avoidance task: Effects of retest period, stimulus type, and demographics.

The approach-avoidance task (AAT) is an implicit task that measures people's behavioral tendencies to approach or avoid stimuli in the environment. In recent years, it has been used successfully to help explain a variety of health problems (e.g., addictions and phobias). Unfortunately, more recent AAT studies have failed to replicate earlier promising findings. One explanation for these replication failures could be that the AAT does not reliably measure approach-avoidance tendencies. Here, we first review existing literature on the reliability of various versions of the AAT. Next, we examine the AAT's reliability in a large and diverse sample (N = 1077; 248 of whom completed all sessions). Using a smartphone-based, mobile AAT, we measured participants' approach-avoidance tendencies eight times over a period of seven months (one measurement per month) in two distinct stimulus sets (happy/sad expressions and disgusting/neutral stimuli). The mobile AAT's split-half reliability was adequate for face stimuli (r = .85), but low for disgust stimuli (r = .72). Its test-retest reliability based on a single measurement was poor for either stimulus set (all ICC1s < .3). Its test-retest reliability based on the average of all eight measurements was moderately good for face stimuli (ICCk = .73), but low for disgust stimuli (ICCk = .5). Results suggest that single-measurement AATs could be influenced by unexplained temporal fluctuations of approach-avoidance tendencies. These fluctuations could be examined in future studies. Until then, this work suggests that future research using the AAT should rely on multiple rather than single measurements.

The role of valence, arousal, stimulus type, and temporal paradigm in the effect of emotion on time perception: A meta-analysis.

Anecdotal experiences show that the human perception of time is subjective, and changes with one's emotional state. Over the past 25 years, increasing empirical evidence has demonstrated that emotions distort time perception and usually result in overestimation. Yet, some inconsistencies deserve clarification. Specifically, it remains controversial how valence (positive/negative), arousal (high/low), stimulus type (scenic picture/facial expression/word/sound), and temporal paradigm (reproduction/estimation/discrimination) modulate the effect of emotion on time perception. Thus, the current study aimed to conduct a meta-analysis to quantify evidence for these moderators. After searching the Web of Science, SpiScholar, and Google Scholar, 95 effect sizes from 31 empirical studies were calculated using Hedges'g. The included studies involved 3,776 participants. The results a highlighted significant moderating effect of valence, arousal, stimulus type, and temporal paradigm. Specifically, negative valence tends to result in overestimation relative to positive valence; the increasing arousal leads to increasing temporal dilating; scenic picture, facial picture, and sound are more effective in inducing distortions than word; the overestimation can be better observed by discrimination and estimation paradigms relative to reproduction paradigms, and estimation paradigm is likely to be the most effective. These results suggest that the effect of emotion on time perception is influenced by valence, arousal, stimulus type, and temporal paradigm. These mitigating factors should be considered by scientists when studying time perception.

Quantitative EEG Changes in Youth With ASD Following Brief Mindfulness Meditation Exercise.

Mindfulness has growing empirical support for improving emotion regulation in individuals with Autism Spectrum Disorder (ASD). Mindfulness is cultivated through meditation practices. Assessing the role of mindfulness in improving emotion regulation is challenging given the reliance on self-report tools. Electroencephalography (EEG) has successfully quantified neural responses to emotional arousal and meditation in other populations, making it ideal to objectively measure neural responses before and after mindfulness (MF) practice among individuals with ASD. We performed an EEG-based analysis during a resting state paradigm in 35 youth with ASD. Specifically, we developed a machine learning classifier and a feature and channel selection approach that separates resting states preceding (Pre-MF) and following (Post-MF) a mindfulness meditation exercise within participants. Across individuals, frontal and temporal channels were most informative. Total power in the beta band (16-30 Hz), Total power (4-30 Hz), relative power in alpha band (8-12 Hz) were the most informative EEG features. A classifier using a non-linear combination of selected EEG features from selected channel locations separated Pre-MF and Post-MF resting states with an average accuracy, sensitivity, and specificity of 80.76%, 78.24%, and 82.14% respectively. Finally, we validated that separation between Pre-MF and Post-MF is due to the MF prime rather than linear-temporal drift. This work underscores machine learning as a critical tool for separating distinct resting states within youth with ASD and will enable better classification of underlying neural responses following brief MF meditation.

Motivated for movement: Beta activation over the motor cortex resulting from intrinsic and extrinsic motivators.

Past work on motivation has primarily studied dichotomous distinctions of motivation (e.g., extrinsic or intrinsic). However, focusing on the overall motivational intensity may be better at accentuating the unique differences within and between varying motivators as it pertains to the impetus to act. Specifically, motivational intensity influences neural patterns of beta band frequency (13-30 Hz) as measured by electroencephalography (EEG) that enable motor-action preparation, a neural correlate of motivated movement. The primary aim of across three experiments was to investigate neural motor-action preparation to modified flanker tasks within achievement (Experiment 1), autonomous (Experiment 2), and extrinsic vs. intrinsic (Experiment 3) motivational contexts. Experiment 1 revealed greater motor-action preparation for challenging trial cues and did not differ in behavioral attentional and performance measures across both trial types. Experiment 2 revealed no significant difference in motor-action preparation, did not differ in behavioral attentional narrowing and had worse behavioral performance in high autonomy relative to low autonomy trials. Experiment 3 revealed greater motor-action preparation for challenging trial cues, did not differ in behavioral attentional narrowing and had a faster performance for reward trials relative to high autonomy trials. These findings suggest motivators of the same category (i.e., intrinsic) may differ in motivational strength, as suggested by a neurophysiological measure of immediate motivated movement planning.

How Does Emotion Influence Time Perception? A Review of Evidence Linking Emotional Motivation and Time Processing.

Emotions have a strong influence on how we experience time passing. The body of research investigating the role of emotion on time perception has steadily increased in the past twenty years. Several affective mechanisms have been proposed to influence the passing of time. The current review focuses on how three dimensions of affect-valence, arousal, and motivation-are related to time perception. The valence-based model of time perception predicts that all positive affects hasten the perception of time and all negative affects slow the perception of time. Arousal is thought to intensify the effects of the influence of valence on time perception. In much of this past work, motivational direction has been confounded with valence, whereas motivational intensity has been confounded with arousal. Research investigating the role of motivation in time perception has found that approach-motivated positive and negative affects hasten the perception of time, but withdrawal-motivated affects slow the perception of time. Perceiving time passing quickly while experiencing approach-motivated states may provide significant advantages related to goal pursuit. In contrast, perceiving time passing slowly while experiencing withdrawal-motivated states may increase avoidance actions. Below, we review evidence supporting that approach motivation hastens the passing of time, whereas withdrawal motivation slows the passing of time. These results suggest that motivational direction, rather than affective valence and arousal, drive emotional changes in time perception.

Motor Preparation and Execution for Performance Difficulty: Centroparietal Beta Activation during the Effort Expenditure for Rewards Task as a Function of Motivation.

Debate exists as to the effects of anxiety in performance-based studies. However, no studies have examined the influence of motivation both in preparation of a motor movement and during movement performance. The present study measured beta activation in preparation for and during execution of the effort expenditure for rewards task (EEfRT), a button-pressing task consisting of easy and hard trials. Results indicated that motor preparation (i.e., reduced beta activation) was greater in preparation for hard trials than for easy trials. Additionally, motor preparation decreased (i.e., beta activation increased) over the course of hard trial execution. These results suggest that motor preparation is enhanced prior to more challenging tasks but that motor preparation declines as participants become closer to completing their goal in each challenging trial. These results provide insight into how beta activation facilitates effort expenditure for motor tasks varying in difficulty and motivation. The impact of these results on models of anxiety and performance is discussed.

Individual differences in motivation and impulsivity link resting frontal alpha asymmetry and motor beta activation.

Previous research has linked neural correlates with motivational traits and measures of impulsivity. However, few previous studies have investigated whether individual differences in motivation and impulsivity moderate the relationship between these disparate neural activity patterns. In a sample of 118 young adults, we used Electroencephalography (EEG) to examine whether behavioral activation and inhibition systems (BIS/BAS) and impulsivity facets (negative urgency, lack of perseverance), moderate the relationship between beta power and resting frontal alpha asymmetry. Regression analyses revealed a novel relationship between lesser beta power and greater left frontal alpha asymmetry (LFA). Moderation analyses suggest this relationship may strengthen as BIS/BAS levels increase, and trait impulsivity levels decrease from the mean. These results are among the first revealing a relationship between two widely investigated neural activity patterns of motivation and provide some indication individual differences moderate this relationship. The limitations of these findings and need for future research are discussed.

Frontal Asymmetry in an approach-avoidance conflict paradigm.

The frontal cortex appears to be asymmetrically related to approach motivation, avoidance motivation, and motivational conflict. Much past work has investigated approach and avoidance motivation, but little work has investigated frontal asymmetry in the face of motivational conflict in part because of the inherent conflict between avoidance motivation and motivational conflict. The current study sought to disentangle the existing confound between avoidance motivation and motivational conflict. In the study, participants selected the likelihood of viewing negative (vs. positive) images for zero reward points (avoidance only condition), or negative (vs. positive) images for the chance to win reward points (approach-avoidance conflict conditions). Participants exhibited greater relative right frontal asymmetry while making percent likelihood selections in the approach-avoidance conflict conditions relative to the avoidance only conditions. Additionally, participants exhibited greater relative right frontal asymmetry while viewing disgust images during trials with the greatest approach-avoidance conflict relative to trials with the lowest approach-avoidance conflict. Together, these results suggest that motivational conflict, and not avoidance motivation, is associated with greater relative right frontal activity.

Revenge is sweet: Investigation of the effects of Approach-Motivated anger on the RewP in the motivated anger delay (MAD) paradigm.

Past research has found that neural activity associated with feedback processing is enhanced by positive approach-motivated states. However, no past work has examined how reward processing changes in the context of revenge. Using a novel aggression paradigm, we sought to explore the influence of approach-motivated anger on neural responses to feedback indicating the opportunity to seek revenge against an offending opponent by examining the reward positivity (RewP), an event-related potential indexing performance feedback. In Experiment 1, after receiving insulting feedback from an opponent, participants played a reaction time game with three trial types: revenge trials, aggravation trials, and no-consequence trials. Results revealed that RewP amplitudes were larger to revenge trial win feedback than no-consequence trial win feedback or revenge trial loss feedback. RewP amplitudes were larger to both aggravation trial win and loss feedback than on no-consequence trials. Experiment 2 examined the influence of approach-motivated anger during the acquisition of rewards on the RewP without the possibility of retribution from the offending individual. Participants played a reaction time game similar to Experiment 1, except instead of giving or receiving noise blasts, participants could win money from the insulter (revenge trials) or a neutral-party (e.g., bank). Results indicated that revenge wins elicited larger RewP amplitudes than bank wins. These results suggest that anger enhances revenge-related RewP amplitudes to obtaining revenge opportunities and further aggravation wins or losses. Anger appears to enhance the pleasurable feelings of revenge.

Frontal asymmetry: A novel biomarker for physical activity and sedentary behavior.

Past research has demonstrated that regular physical activity provides a myriad of physical, mental, and emotional benefits. The decision of whether to partake in physical activity (PA) or remain sedentary appears to be partially influenced by motivational and emotional systems. Research suggests left frontal alpha asymmetry is a neural marker of approach motivation. However, studies have not explored whether habitual levels of PA and sedentary behavior relate to this neurophysiological signal. Across two studies, individuals completed measures of habitual PA and sedentary behavior using the International Physical Activity Questionnaire-Short Form. Then, resting electroencephalography activity was recorded. Results of Study 1 (N = 32, 72% women) indicated that more time spent sitting on both weekdays and weekend days were associated with less left frontal asymmetry (r = -.45, p = .027, and r = -.55, p = .005, respectively). Study 2 recruited a larger sample (N = 96, 31% women) and investigated moderators. Greater levels of moderate (r = .27) and total (r = .29) PA were associated with greater left frontal asymmetry (ps < .05), and the relationship between sedentary behavior and less left frontal asymmetry was moderated by sex (weekday: ß = .62, p = .011; weekend day: ß = .41, p = .034). Our results suggest that left frontal asymmetry may be a novel neurophysiological marker for PA and sedentary behavior.

An EEG Study of Children With and Without ADHD Symptoms: Between-Group Differences and Associations With Sluggish Cognitive Tempo Symptoms.

Objective: We examined differences between those with and without ADHD symptoms on resting state electroencephalography (EEG) indices and unique relations with sluggish cognitive tempo (SCT) symptoms. Method: Children with ADHD symptoms (n = 21) and healthy controls (n = 20) were assessed using rating scales, a neuropsychological task measuring sustained attention and inhibitory control, and EEG activity during a resting state period. Between-group, correlational, and regression analyses were conducted. Results: Large differences (particularly for theta/beta ratio in frontal and frontocentral regions) were found on EEG measures between those with and without ADHD symptoms. While ADHD and SCT symptoms both related to sustained attention on a computerized task, only ADHD symptoms were related to frontal and frontocentral theta/beta ratio. Conclusion: Results support the conclusion that ADHD symptoms are strongly associated with theta/beta ratio in frontal and frontocentral regions. Future studies should explore unique neurophysiological correlates of SCT.

Effortful control of motivation, not withdrawal motivation, relates to greater right frontal asymmetry.

Past models of frontal asymmetry have associated greater relative right frontal cortical activity with greater withdrawal motivation and greater relative left frontal cortical activity with greater approach motivation. However, this traditional model of frontal asymmetry leaves little to no room for the control processes that engage and regulate these emotional and motivational systems. A growing body of literature suggests that greater relative right frontal activation may be associated with greater regulatory control (Gable et al. 2018). However, this work confounded regulatory control and motivational direction. The current studies sought to test the competing hypotheses that currently exist in the literature by examining whether greater right frontal activation is more closely associated with regulatory control or withdrawal motivation. In Study 1, participants listened to negative and neutral sounds while suppressing their emotional reactions or listening naturally. Greater relative right frontal activation during the sound clips was associated with participants' reported effort when attempting to suppress their motivational responses to negative stimuli. Greater relative right frontal activation did not relate to experiencing negative affect. In Study 2, participants could win money by looking at a negative or neutral image or escape from looking at them for no reward. Greater relative right frontal activation was associated with looking at the negative pictures longer when there was a possibility of reward, but not when the possibility of reward was absent. Together, these studies suggest that it is the affective control of emotion rather than negative affect driving greater relative right frontal asymmetry. Additionally, these studies suggest that motivational conflicts engage effortful control.

Neural and Attentional Correlates of Intrinsic Motivation Resulting from Social Performance Expectancy.

Some models of motivation distinguish between intrinsic and extrinsic motivation. While past work has examined the neural and cognitive correlates of extrinsic motivation, research on intrinsic motivation has relied primarily on behavioral measures of performance and learning. In particular, no past work has examined the neural and cognitive correlates of social performance expectancy, which is linked to intrinsic motivation. The current study manipulated expectancy of difficult (vs. easy) trials on a cued flanker task and assessed attentional scope and performance. EEG was used to examine motor-action preparation as measured by suppression of beta band activity over the motor cortex and feedback processing as measured by the Reward Positivity (RewP). Results revealed expectancy of difficult (vs. easy) trials narrowed attentional scope, reduced beta activity over the motor cortex, and enhanced RewP amplitudes to win feedback. These findings suggest that enhancing intrinsic motivation through expectancies of positive social comparison engages similar neural and cognitive correlates as extrinsic motivators high in motivational intensity.

Intertrial variability in emotive reactions to approach-motivated positive pictures predicts attentional narrowing: The role of individual differences.

Previous research has found that high approach-motivated positive affect narrows cognitive scope. Additionally, this narrowing of cognitive scope in high approach-motivated states is related to neural correlates of motor-action preparation, including beta suppression over the motor cortex. However, past studies have only examined these effects averaging across trials, without accounting for individual variability from trial-to-trial. Across two studies, the present research investigated how individual differences in motor-action preparation related to individual differences in cognitive narrowing. Experiment 1 had participants view affective or neutral pictures and then respond to a Navon letters task. Results indicated that there was a more positive relationship between beta suppression to approach-motivated positive pictures and local targets than either beta suppression to approach-motivated positive pictures and global targets or beta suppression to neutral pictures and local targets. Experiment 2 replicated these results using alcohol pictures. These experiments suggest that individual differences in beta suppression predict greater narrowed cognitive scope to appetitive pictures. Assessing individual differences in neurophysiological and emotive responses to pictures reveals individual variations in cognitive processing.