Event-Related Potential Study on the Effect of Ego Depletion on Perceptual Anticipation Under Negative Emotion

Summary

Here, we propose an investigation using event-related potential (ERP) methodology to examine the underlying mechanisms through which ego depletion influences perceptual anticipation in tennis-trained undergraduates under negative emotion.

Abstract

The present study employed a combination of behavioral and event-related potential (ERP) measures to investigate the effect of ego depletion on perceptual anticipation in tennis-trained undergraduates under negative emotion. The findings will provide a theoretical foundation for enhancing training efficacy in this specific population. Negative emotion was induced by film clips, while ego-depletion was elicited through a Stroop task. Perceptual anticipation was evaluated using temporally occluded tennis videos. Under negative emotion, participants exhibited shorter reaction time and higher accuracy either in the low ego-depletion state or at 160 ms after hitting the ball. Additionally, there was a shorter N2 peak latency at 160 ms after hitting the ball than at the moment of hitting the ball. The peak amplitudes of N2, P3, and LNC mean amplitude were significantly lower under the low ego-depletion state than those under the high ego-depletion state (p < 0.05). The peak amplitudes of N2 and P3 were higher at the moment of hitting the ball than at 160 ms after hitting the ball. Under negative emotion, tennis-trained undergraduates exhibited faster perceptual anticipation speed, higher accuracy, and a reduced allocation of cognitive resources in a low ego-depletion state. Compared to the moment of hitting the ball, tennis-trained undergraduates exhibited better speed-accuracy, earlier attention control, and reduced allocation of attentional and cognitive resources at 160 ms after hitting the ball. The findings suggest that tennis coaches should enhance players' emotional self-regulation skills, optimize training environments, and reduce ego depletion to improve their performance.

Introduction

Tennis is a sport characterized by unpredictable ball trajectories, high speeds, and a wide range of shot placements, requiring players to possess strong perceptual anticipation skills. Perceptual anticipation refers to the ability to predict the outcome of an impending event by utilizing advanced information obtained through sensory channels¹. Accumulating evidence shows that athletes demonstrate domain-specific advantages in prediction speed and accuracy compared to non-athletes². Tennis players demonstrate superior action anticipation capabilities under information-constrained conditions^3,4. Research has shown that such perceptual anticipation advantages in tennis players can be influenced by factors such as emotional state⁵ and ego depletion⁶. Prolonged exertion of self-control depletes limited mental resources, leading to a state known as ego-depletion⁶. This study aims to address the following question: What are the behavioral and event-related potential (ERP) correlates of perceptual anticipation under negative emotion, across varying levels of ego depletion and temporal occlusion conditions? This issue remains unexplored and warrants further investigation.

Empirical studies have established that affective valence (i.e., the positive or negative direction of an emotional experience) exerts bidirectional influences on anticipatory performance: positive emotional states enhance processing speed (reduced reaction time) and decision accuracy, likely by facilitating attentional engagement and streamlined sensorimotor integration⁷ while negative affective states disrupt cognitive processing in athletes across various sports. For instance, basketball athletes demonstrate both increased response latency and decreased motor velocity when processing conflict stimuli under negative emotional conditions⁸. Therefore, the processing of negative emotions occupies more cognitive resources and significantly interferes with the anticipation of movement speed⁹. Ego depletion also influences athletes' perceptual decision-making and visual search in sports contexts. For instance, basketball players exhibit superior decision-making performance under low ego depletion conditions⁶. In contrast, high ego depletion exerts detrimental effects on athletes' sustained attention¹⁰, working memory¹¹, and decision-making in sports¹². Meta-analysis revealed that ego depletion exerts a medium effect size on sports performance¹³,¹⁴. Specifically, individuals enter a state of ego depletion after performing self-control tasks, which subsequently impairs their operational performance in athletic tasks. Finally, an intrinsic relationship exists between emotional valence and ego depletion. Negative emotions lead to greater depletion of self-control resources¹⁵, resulting in poorer performance on subsequent self-control tasks¹⁶. Individuals under high ego depletion exhibit more pronounced attentional bias toward negative emotional information¹⁷. While both negative emotion and ego depletion affect perceptual anticipation, few electrophysiological studies have investigated their combined effects.

The primary ERP components associated with perceptual anticipation in tennis include N2, P3, and the late negative component (LNC). Previous research has demonstrated that both N2 and P3 components are strongly correlated with cognitive functions underlying sports-related perceptual anticipation^18,19,20. For instance, Zhang and Zhou's study revealed that tennis experts demonstrate superior performance in identifying target stimulus characteristics during dynamic offensive-defensive transitions, as evidenced by earlier onset latencies of N2 and P3 components²¹.The research revealed that badminton experts exhibit faster stimulus identification and encoding speeds with greater mental resource allocation, as reflected by shorter P3 peak latency and higher P3 amplitude²². Furthermore, the study showed that tennis experts invest more cognitive effort in scene representation during perceptual anticipation tasks, evidenced by higher LNC mean amplitude¹⁹. Compared to tennis novices, tennis experts exhibit higher N2 amplitude²³, shorter P3b latency, and higher P3b amplitude²⁴ during perceptual anticipation tasks. In ERP studies on perceptual anticipation, researchers commonly employ spatial occlusion techniques^3,23 and temporal occlusion techniques^21,25 as research paradigms. Among these methods, temporal occlusion techniques can demonstrate the importance of early visual information for athletes' anticipatory judgment in receiving serves²⁶, characterized by strong objectivity and good ecological validity. Therefore, this study adopts temporal occlusion as the experimental paradigm to investigate ERP characteristics of tennis-trained undergraduates' perceptual anticipation, with N2, P3, and LNC selected as the ERP components for evaluating anticipatory performance.

The electrophysiological mechanisms by which negative emotion and ego depletion jointly modulate experts' advantages are still unknown. Event-related potential (ERP) methodology provides millisecond temporal resolution, enabling precise detection of cortical electrophysiological activity during perceptual anticipation processes²⁷. This study employed temporal occlusion techniques, presenting video footage of rally phases from tennis matches as perceptual anticipation stimuli. We used event-related potential (ERP) measures to examine the behavioral and electrophysiological effects of ego depletion on perceptual anticipation in tennis-trained undergraduates under negative emotion. This study will provide theoretical insights into expanding the categories of factors that influence perceptual anticipation in tennis-trained undergraduates. Furthermore, the present study will offer scientific evidence to optimize training methodologies and enhance competitive performance. Based on this theoretical framework, we hypothesize that under negative emotion, tennis-trained undergraduates exhibit superior perceptual prediction performance when in a state of low ego depletion and with an extended time-blocking condition, as manifested by shorter reaction time, higher accuracy, and reduced N2 and P3 peak amplitudes.

Protocol

The protocol of the current experiment was approved by the Human Experiment Ethics Committee of the first author's affiliated university (Project identification code: 2024010).All participants provided informed consent for this study.

1. Experimental subjects

1. Conduct sample size estimation a priori using G*Power 3.1.9²⁸. Set parameters at α = 0.05 (two-tailed), power = 0.80, and effect size f = 0.25. Analyze the data using a 2 (ego-depletion: high versus low; between-subjects) x 2 [time-point: T1(the moment of hitting the ball) versus T2(160 ms after hitting the ball); within-subjects] mixed-design ANOVA. Target a minimum sample size of N = 24 to detect hypothesized effects.
2. Recruit a sample of 30 male university students specializing in tennis, with a mean age of 21.73 ± 1.048 years and a mean training experience of 2.967 ± 0.507 years. Randomly assign participants to a high ego-depletion group and a low ego-depletion group, with 15 participants in each.
3. Ensure that all participants meet the following inclusion criteria: (1) good physical health with no history of psychiatric or neurological disorders; (2) adequate sleep and a neutral emotional state; (3) familiarity with tennis technical tactics and at least two years of tennis training; (4) normal color vision and normal or corrected-to-normal visual acuity; (5) right-handed; (6) no prior participation in similar experiments. Exclude participants who fail to meet these criteria.
4. Brief participants fully on procedures, acclimate them to the laboratory, and obtain written informed consent.

2. Experimental materials

1. Select film clips from the Chinese Affective Video System²⁹ to elicit the target emotional state, given their established efficacy in direct emotion induction³⁰. Use the clip NUAN CHUN as the validated negative emotion induction stimulus (Cronbach's α > 0.79).
2. Calibrate auditory stimuli to 65 dB SPL using a sound level meter positioned at the participant's head prior to the experiment. Set the duration of each affective clip to approximately 100 s. Secure approval from the Institutional Ethics Committee for Human Research prior to data collection.
3. Administer the 9-point emotion rating scale adapted from the Positive and Negative Affect Schedule (PANAS)^31,32. Interpret higher scores as a stronger negative emotion. Confirm convergent validity between self-reported states and physiological measures³².
4. Adopt the Stroop paradigm³³ to induce high- and low-self-control depletion states. Construct stimuli using four Chinese characters: red, yellow, blue, and green. Randomly pair each character with an incongruent ink color (red, yellow, blue, green) per trial. Deliver trials via E-Prime 2.0, randomizing presentation sequences.
5. Interpret stimulus-color incongruence as inducing cognitive conflict and recruiting higher executive resources. Treat stimulus-color congruence as eliciting no conflict and requiring lower executive resources¹¹. Assign the high ego-depletion group a Stroop task consisting of 80 congruent trials and 80 incongruent trials. Assign the low ego-depletion group a control Stroop task comprising 160 congruent trials only.
6. Administer a 3-item validation questionnaire³⁴ to assess Stroop-induced self-control depletion states. Measure the following dimensions: Subjective effort expenditure in suppressing word-meaning interference during color naming; perceived fatigue levels; self-reported energy depletion. Apply positive scoring, with higher total scores indicating higher depletion.
7. Extract video stimuli from 2019 US Open men's singles high-definition match recordings. Select the final three strokes of rally neutral-phase segments, terminating at: Opponent's stroke impact moment (T1); 160 ms post-impact (T2). Generate 460 initial clips (230 left-court returns/ 230 right-court returns), each with duration: 2000 ms, format: AVI, and frame rate: 25 fps.
8. Conduct expert validation with 10 certified tennis-trained undergraduates and 3 professional coaches following Zhang's methodology²¹. Select final stimuli (58 left-court/58 right-court clips; 116 total). Program stimuli in E-Prime 2.0 and randomize presentation order.

3. Experimental procedure

1. Obtain written informed consent and administer the PANAS upon participant arrival. Screen participants based on MAS results.
2. Fit participants with a 64-channel EasyCap EEG system. Apply conductive gel and maintain all electrode impedances below 10 kΩ. Deliver standardized task instructions emphasizing: maintenance of upright seated posture; minimization of head movements; and consistent visual fixation at 70 cm from screen center.
3. Conduct practice phase: Complete Stroop task practice block (8 trials with performance feedback); complete perceptual anticipation training block (16 trials with feedback).
4. Implement formal experimental phase in sequence: Induce emotion (100 s procedure), then administer emotional state self-assessment, followed by executing the Stroop task, then verify ego-depletion state, and finally perform the perceptual anticipation task.
5. Assign trial quantities as follows. Stroop task: Begin each trial with a 500 ms presentation of a fixation cross. Then, present the Stroop stimulus for 2000 ms or until a response is made (whichever comes first). Consider a response valid only if it occurs within the 2000 ms window following stimulus onset. Set the inter-trial interval (ITI) to 500 ms. Ensure all visual stimuli subtend approximately 3° x 1.5° of visual angle at a viewing distance of 70 cm.
6. Perceptual anticipation task: 50 left-court return trials, 50 right-court return trials. Present a red fixation cross (+) for 500 ms at the start of each trial, followed by a 2000 ms perceptual anticipation video stimulus. Then, display a response screen for 2000 ms, instructing participants to predict the direction of the ball trajectory from the preceding video. Set the ITI to 500 ms. Randomize all trial sequences. Connect the monitor to a Windows 10 control system.
   NOTE: Refer to Figure 1 for experimental paradigm schematics. Stimuli were displayed on a 19-inch LCD monitor (1920 x 1080 pixel resolution, 100 Hz refresh rate) controlled by a Windows 10 system.

4. Response protocol

1. Instruct participants to indicate font colors by keypresses using standardized mapping in the Stroop task: Red - D key; Yellow -F key; Blue -J key; Green - K key.
2. Require speeded forced-choice responses for ball trajectory prediction in the perceptual anticipation task: Left-court returns - F key; Right-court returns - J key. Record accuracy and reaction time (RT) as primary measures.
3. Initiate response window at 2000 ms post-video onset (t = 0). Maintain an active window for 2000 ms (2000-4000 ms epoch). Measure RT relative to the video onset frame. Code non-responses within the window as omission errors.

Figure 1: Schematic diagram of the experimental procedure. Please click here to view a larger version of this figure.

5. Data processing

1. Record reaction time and accuracy rates by E-Prime 2.0 during Stroop and perceptual anticipation tasks.
2. Analyze behavioral data in SPSS 22.0 using the following protocol: Identify and exclude outliers where individual reaction time/accuracy exceeds ± 3SD from the group mean. Use an independent-samples t-test to assess the effectiveness of negative emotion and ego-depletion manipulations. Conduct 2 x 2 repeated-measures ANOVAs for RT and accuracy. For post hoc comparisons, use Tukey's LSD (Least Significant Difference) tests. Apply the Greenhouse-Geisser correction when the sphericity assumption is violated.
3. Acquire EEG signals using a 64-channel actiCAP system positioned per the 10-10 international system³⁵, using AFz as the ground electrode. Extract epochs from -200 ms to 2000 ms relative to stimulus onset, using -200-0 ms as baseline. Retain an average of 36 artifact-free trials per condition for ERP averaging. Confirm that trial counts did not differ significantly across conditions (p > 0.05).
   NOTE: During online acquisition, the reference electrode was set at FCz, with subsequent offline conversion to average reference. Signal acquisition employed a 1000 Hz sampling rate with analog bandpass filtering (0.01-100 Hz).ERP signals were filtered (0.01-35 Hz) and cleaned using ICA-based artifact removal (±80 µV threshold).
4. Focus on electrodes over the frontal (F1, F2, Fz, F3, F4, Fp1, Fp2, Fpz) and parietal (Pz, P3, P4) regions for analysis, selecting these sites a priori based on research objectives and existing literature^21,36. Choose these electrodes because they reliably generate ERP components (e.g., N2, P3, LNC) sensitive to cognitive control processes and sensory integration for anticipatory judgment. Include the occipital electrode (POz) to control for early visual processing.
5. Define the ERP analysis parameters (time windows and electrode sites) based on the grand-average and difference wave topographies.
   N2: 150-300 ms window | Electrodes F3, F4, Fz, Fpz → Extract peak latency/amplitude
   P3: 250-450 ms window | Electrodes P3, P4, POz, Pz → Extract peak latency/amplitude
   LNC: 600-1200 ms window | Electrodes Fp1, Fp2, Fz, F1, F2 → Calculate mean amplitude
6. Analyze all ERP metrics using RM-ANOVA in SPSS 22.0. Apply Greenhouse-Geisser correction for sphericity violations. Conduct Bonferroni-adjusted post hoc tests for significant main effects. Interpret significant effects (p < 0.05) with component-specific theoretical frameworks.

Results

Effects of negative emotion and ego depletion induction

For the negative emotion induction, self-reported emotional ratings demonstratedsignificantly higher post-induction scores (6.93 ± 1.26) compared to pre-induction baseline (4.43 ± 1.19), t = -9.40, p < 0.001.The results demonstrate that the NUAN CHUN film clip effectively induced a negative emotional state in participants. On the ego-depletion m...

Discussion

This study employed event-related potential (ERP) techniques to investigate the neural mechanisms underlying the effects of ego depletion on perceptual anticipation in tennis-trained undergraduates under negative emotion. Tennis-trained undergraduates in the low ego-depletion state demonstrated significantly shorter perceptual anticipation reaction time, higher accuracy, and lower N2/P3 peak amplitudes and LNC mean amplitude compared to the high ego-depletion state under negative emotion. Compared to the moment of hittin...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Abrasive gel	Beijing Flying Star Electronic Technology Co., Ltd.	4oz	Remove keratin, dead skin cells, and oils from the scalp surface to further minimize skin-electrode impedance.
BrainAmp SN	Brain Products	AMP12081737 Standard	Acquisition of electroencephalogram (EEG) signals
Electrolyte gel	Beijing Flying Star Electronic Technology Co., Ltd.	Easy Gel 32oz	Reduce impedance and ensure high-quality signal transmission.
E-prime Professional	Psychology Software Tools	2.0.10.92	Psychology Experiment Software