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Article

Psychophysiological Effects of Shooting Tree Light Colors on Alertness: A Controlled Laboratory Study

by
Xudong Wang
*,
Jiali Mo
,
Yuqi Zhou
and
Ziyu Long
College of Human Settlements, North China University of Water Resources and Electric Power, Zhengzhou 450046, China
*
Author to whom correspondence should be addressed.
Buildings 2025, 15(16), 2907; https://doi.org/10.3390/buildings15162907
Submission received: 18 June 2025 / Revised: 7 August 2025 / Accepted: 14 August 2025 / Published: 17 August 2025
(This article belongs to the Special Issue Advances in Sustainable Lighting for Health and Comfort in the Built Environment)
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Abstract

As an essential component of the built environment, outdoor artificial lighting at night, has a profound impact on visitors’ experience quality. Research on the light environment extends beyond visual effects to encompass broader psychophysiological impacts, such as perception, emotion, and public health. Shooting tree lights (STLs) are a distinctive type of outdoor lighting, commonly installed in landscape environments. This study aims to investigate the effects of different colors (yellow, red, green, and blue) of STL on alertness at night. Sixty participants took part in an experimental design assessing the impact of four different colors on electroencephalogram (EEG) and self-reported alertness. Our results indicate that STL color is a significant factor influencing physiological alertness levels. Exposure to yellow light reduced beta power, diminished alertness, and enhanced relaxation and comfort compared to red, blue, and green light. The study also identified variations in alertness based on age and gender. With respect to age, younger individuals exhibited greater alertness, while women were more alert than men. This study suggests that yellow light is generally more favorable than other colors in enhancing subjective light comfort. These findings underscore the importance of prioritizing yellow-colored STLs in landscape planning and design to promote relaxation and comfort for nighttime visitors.

1. Introduction

The outdoor landscape environment is an essential space for urban residents to engage in various social activities, relaxation, and entertainment [1]. With societal development and improved living standards, the demand for urban night lighting has significantly increased. Creating aesthetically appealing nightscapes is considered fashionable, as it energizes residents and fosters a modern atmosphere [2]. Municipalities should prioritize user experience when selecting lighting applications [3]. Various types of landscape lighting primarily constitute the urban nightscape, significantly impacting public psychological and physiological health [4,5,6,7,8]. Light can positively or negatively influence human health [9], affecting perception [3,10], mood [11,12,13], and behavior [14,15,16]. This underscores the need for systematic evaluation of environmental experiences with landscape lighting in nighttime environments. The present study employs a psychophysiological approach to evaluate environmental perceptions and preferences regarding outdoor landscape lighting.
The literature review in this study primarily focuses on research conducted in outdoor settings. The quality of visitors’ experiences is significantly influenced by outdoor artificial nighttime lighting. When assessing outdoor lighting applications, considering how lighting interacts with other landscape properties, such as the configuration of built features [17,18] and vegetation [19,20,21], is essential. Perceptions and preferences for different lighting applications should also take into account the specific landscape characteristics of the site.
Boyce et al. have pointed out that people feel safer under conditions of higher illuminance in urban car parks, with the light spectrum having a relatively minor impact compared to illuminance [22]. Similarly, Nikunen et al. investigated how nightscapes affect perceived feelings of restorativeness, preference, and fear in relation to various scene elements. High-quality lighting is often regarded as a key feature of defensible space, essential for ensuring comfort and security, particularly for individuals experiencing anxiety [23]. Lee et al. analyzed the subjective characteristics of lighting in nightscapes and examined the correlation between lighting design and public perceptions of nightscapes [24]. Conversely, Paksarian et al. have highlighted that outdoor artificial light at night was associated with poorer sleep patterns, mood disturbances, and anxiety disorders in adolescents [13]. Patching et al. proposed a novel method of random environmental walking to complement existing approaches for evaluating urban lighting applications, with potential to uncover behavioral preferences for various lighting designs [25].
Outdoor lighting can positively or negatively affect human physiology. These physiological effects can be precisely measured using metrics such as electroencephalography (EEG), heart rate (HR), and blood pressure. Kim et al. proposed guidelines for nightscape planning by using EEG technology and conducting surveys to identify the unique characteristics of nightscapes. Kim et al. investigated changes in relative alpha and beta wave activity, as well as perceived fear levels, in response to twelve different nightscape settings [26]. Rahm et al. assessed human responses to urban outdoor lighting under controlled laboratory conditions [14,16].
Previous research has demonstrated the effects of light on people. However, various forms of lighting exist in the built environment. As a distinct type of nighttime landscape lighting, shooting tree lights (STLs) are widely employed in parks, squares, residential areas, and other living environments. Despite the widespread use of outdoor landscape lighting, its impact on people’s emotional and perceptual experiences in open spaces remains poorly understood.
This study aimed to investigate how different colors of shooting tree lights (STLs) influence alertness, using psychophysiological performance metrics. Insights from this research can contribute to optimizing environmental lighting design to better support cognitive performance and psychological well-being. By investigating the effects of light color in nocturnal urban environments, this study contributes to the expanding body of evidence on environmental lighting and its implications for human health and behavior. It further aims to inform the optimization of urban lighting design by aligning illumination strategies with human biological rhythms, enhancing cognitive alertness when required, and promoting psychological relaxation in appropriate settings, aiming to enhance urban outdoor spaces and support human activities at night.

2. Materials and Methods

2.1. Stimuli

Lighting serves as the primary medium for perceiving the nighttime visual environment, and currently, diverse forms of nighttime landscape lighting are employed in urban parks [8,27,28], potentially influencing both physiological and psychological responses [29,30]. Shooting tree lights, which represent one of the most common lighting techniques in landscape design, are widely employed in urban parks both domestically and internationally [31,32]. In this study, the stimuli consisted of four distinct light colors of shooting tree lights (Guangzhou Junyue Culturism Lighting Equipment Co. Ltd., Guangzhou, China)., each representing a specific wavelength band: red (660 nm), yellow (590 nm), blue (460 nm), and green (555 nm). These light colors were selected to examine their effects on human alertness. Accordingly, a commonly found landscape tree in urban park was selected for illumination (height: 9 m, diameter at breast height (DBH): 18 cm, crown width: 4.5 m). Shooting tree lights were positioned 30 cm away from the tree trunk at an elevation angle of 85°. All four lighting color conditions were generated using a single programmable LED landscape lamp (36 W, 50 Hz). The luminaire includes four independent light channels corresponding to red, green, blue, and yellow diodes, each emitting a narrow wavelength band. During the experiment, only one color channel was activated at a time to ensure consistent and isolated stimulation across conditions. Finally, four photographs of trees illuminated by the shooting tree lights in different colors were captured at the same location using a camera with a 16:9 aspect ratio. These images were then used as standardized visual stimuli in the experimental procedure.

2.2. Participants

During subject recruitment, to avoid cultural bias, we recruited 60 subjects of Chinese nationality from North China University of Water Resources and Electric Power, classified by age and gender groups, with detailed demographic information provided in Table 1.
All subjects were screened for health issues before participating in the experiment to ensure they had not consumed alcohol or smoked, were not colorblind, and were not diagnosed with intellectual disabilities. Additionally, it was ensured that each subject received adequate sleep prior to the experiment. Informed consent was obtained from the subjects prior to conducting the relevant tests. The study strictly complied with the Declaration of Helsinki and China’s ethical review regulations and posed no potential risks to participants’ physical or mental health or privacy rights. This human study was approved by Ethics Committee, College of Architecture, North China University of Water Resources and Electric Power—approval: NCWU-SA-2023-002.

2.3. Measurement Tools and Indicators

2.3.1. Subjective Measurements

The subjective questionnaire selected for this study was the Karolinska Sleepiness Scale (KSS), which is designed to assess an individual’s level of alertness in a given environment. This scale has been widely used in previous studies [33,34,35,36]. Using this scale, subjects indicate which level best reflects the psychophysiological status being experienced. It is helpful for assessing the changes in response to environmental factors. The level of alertness was quantified using the KSS, a nine-point standardized scale ranging from 1, “extremely alert,” to 9, “very sleepy.” To further illustrate the variability in nighttime KSS alertness scores, the scale was adjusted to visualize the mean ± standard deviation, with 0, “neither alert nor sleepy” defined as the zero baseline (−4, “extremely alert”; 4, “very sleepy”), to capture a detailed perceptual response to stimuli.
Although the KSS was originally developed to assess alertness in relation to circadian rhythms, environmental influences, and pharmacological factors, it has been widely validated in short-term laboratory experiments to evaluate rapid psychophysiological changes induced by light stimuli. Recent research has demonstrated that brief exposures to colored light (e.g., blue or red light) can significantly alter KSS scores, even in controlled indoor settings, without necessitating circadian phase shifts [33,36,37]. In this study, the scale was used to assess transient alertness states following exposure to different colors of shooting tree lights. Its application focused on capturing immediate responses to ambient light stimuli, a method commonly employed in studies examining alertness under varying lighting conditions.

2.3.2. Physiological Measurements

The acquisition equipment for this study was supplied by King far, and EEG activity was recorded using an Ergo LAB (v3.17.7) wearable EEG device (Beijing King far Co., Ltd., Guangzhou, China). The EEG device operates with a sampling rate of up to 1024 Hz and follows the international 10–20 standard system with 16 channels. This device is extensively used in environmental psychological research [38,39]. In this experiment, all data recording, acquisition, and export were carried out using Ergo LAB 3.0 software. Based on frequency domain analysis, five main EEG wave frequencies were identified: delta (1–4 Hz), theta (4–8 Hz), alpha (8–13 Hz), beta (13–30 Hz), and gamma waves (above 30 Hz). Beta waves have been shown to respond to human alertness, with changes being more pronounced in the frontal and parietal regions [40,41]. In this study, we analyzed beta (13–30 Hz) waves concentrated in the frontal (F3, F4) and parietal (P3, P4) regions of the brain.

2.4. Experimental Procedure

The experiment was conducted in December 2023 under controlled laboratory conditions. The laboratory room measured 6 × 12 × 4.5 m, with temperature and relative humidity maintained at 24 °C and 30%, respectively, under a grey-light environment (illuminance ≈ 20 lx). The room was furnished with a table and chair positioned centrally, along with a monitor and a laptop. Experimental photographs were 1080 × 1920 pixels in size, with a resolution of 300 ppi, and featured a black background. Participants were asked to place all electronic devices, including mobile phones, outside the experiment area to avoid electronic interference. All experiments were conducted in the same physical location within the laboratory, and only one participant was tested at a time to ensure consistency. Before the experiment, the researcher set up the EEG equipment for each subject and provided an introduction to the experimental precautions and instructions. Prior to the playback of the stimulus material, subjects were asked to sit still for 3 min with their eyes closed to collect baseline EEG data in the resting state. Afterward, the first subjective questionnaire was completed within one minute. Subsequently, subjects viewed four photographs of different colors of shooting tree lights (displayed on a black background), which were presented randomly (without repetition) for 1 min each, with a 10-s interval between photographs to reduce fatigue. The use of photographic representations, rather than live environmental lighting, was a deliberate choice to control for multisensory and ambient confounding factors, which has been widely adopted in similar environmental perception studies. Moreover, this approach has been validated in EEG-based research as an effective method to measure visual stimuli and eliminate environmental variability [16,26]. During the experiment, subjects were asked to minimize body movements to avoid interfering with EEG data and to ensure the accuracy of data acquisition. At the end of the experiment, the researcher removed the equipment, allowing subjects to complete the subjective questionnaire scale. The detailed experimental flow is shown in Figure 1.

2.5. Statistical Analysis

This study employed a repeated measures design. As the normality of the data could not be assumed, a Friedman rank-sum test was applied to data that did not follow a normal distribution during data analysis. ANOVA was applied to data that followed a normal distribution, and Bonferroni post hoc comparisons were performed to observe the effect of different variables on human alertness. Both the experimental data and statistical analyses were performed using SPSS software (IBM SPSS Statistics 27). Data visualization was performed using Origin 2021, and results were expressed as mean ± standard deviation.

3. Results

3.1. EEG

Descriptive statistical analysis revealed that baseline EEG data did not follow a normal distribution. Comparison between baseline and the four light conditions showed significant differences between groups (F = 39.693, p < 0.001), with the following mean ranks: baseline (R = 2.13), red light (R = 3.53), yellow light (R = 2.68), blue light (R = 3.72), and green light (R = 2.93). Differences between the baseline and the four lighting conditions were analyzed using post hoc tests. As shown in Figure 2, exposure to all four light colors significantly affected brain activity compared to the baseline. Notably, alertness levels were higher under red and blue light environments (p Baseline/Red < 0.010; p Baseline/Blue < 0.001). The mean beta power, which is associated with heightened alertness, increased under all four colored light conditions, indicating that variations in nighttime lighting can modulate human alertness.

3.1.1. Effect of Different Light Colors of Shooting Tree Lights on Alertness

The mean beta power, after natural logarithmic transformation for different light colors, was found to be statistically significant (S–W test > 0.05), further investigating the effect of different light colors of shooting tree lights on alertness. The analysis revealed a significant change in mean beta power (after natural logarithmic transformation) across different light colors (F = 5.451, p = 0.002). The Huynh–Feldt method was applied to correct for ε = 0.865 adjusted degrees of freedom. The corrected result was F (2.595, 153.081) = 8.826, p = 0.0001, bias η2 = 0.130. Bonferroni-corrected comparisons of mean beta power differences revealed significant differences between yellow light and red and blue light (p Yellow/Red = 0.010, p Yellow/Blue = 0.001), as well as between green light and red light, and green light and blue light (p Green/Red = 0.042, p Green/Blue = 0.019). No significant difference was found between red light and blue light, or between yellow light and green light (Figure 2). The results showed that exposure to red and blue light resulted in higher mean beta power compared to yellow and green light, suggesting that red and blue light enhance human alertness. In contrast, yellow light exhibited the lowest mean beta power among the four light colors, indicating that exposure to yellow light reduces alertness, promoting greater relaxation and stress reduction.

3.1.2. Effect of Age on Alertness

The experiment was designed to investigate whether there are differences between age groups in response to different light colors of the shooting tree lights. The results revealed no significant difference between yellow and green light across different age groups, while significant differences were found between red and blue light for different age stages: for red, F (2, 57) = 3.452 (p = 0.038), whereas for blue, F (2, 57) = 3.544 (p = 0.035). Bonferroni post hoc multiple comparisons were conducted to test for differences between age groups, with significance set at p < 0.05. In Figure 3, significant differences were observed between youth and old age for red and blue light (red (p Youth/Old = 0.034); blue (p Youth/Old = 0.030)), but no significant differences were found between middle age and old age. The mean beta values for youth were significantly higher than those for old age under red and blue light, with middle-aged values falling in between. Although no significant differences were found between age groups for yellow and green light, a general trend of decreasing mean beta power with increasing age was observed. However, exposure to red and blue light resulted in a significantly greater increase in mean beta power in youth compared to old age. Based on changes in mean beta power across young, middle-aged, and older individuals, the effect of light exposure on alertness was found to be weaker with increasing age under these four light colors.

3.1.3. Effect of Gender on Alertness

Regarding gender differences in alertness, Figure 4 shows no significant difference between yellow and green light attributable to gender. However, for red and blue light, significant differences were found between gender groups (t red = −2.456, p = 0.017; t blue = −2.579, p = 0.012). The mean beta values were significantly higher for female participants than male participants in red and blue light environments. Although no significant differences were observed between the gender groups in yellow and green light environments, the overall trend favored higher values for women. These findings indicate that women exhibit greater alertness than men under yellow, green, blue, and red light.

3.2. Subjective Evaluation

Since the KSS scale exhibits variations in scores across different times and states, we employed the intragroup correlation coefficient (ICC) to evaluate the reliability of the scoring results. The ICC value for a single measure was found to be 0.777 (confidence interval: 0.549–0.967), indicating good consistency in the evaluation.
Descriptive statistics were calculated for the KSS scale (baseline 2.3 ± 1.10, red −1.85 ± 1.52, yellow 1.9 ± 1.14, blue −2.71 ± 0.99, green 0.98 ± 1.39), with the score order as baseline > yellow > green > red > blue (Figure 5). A significance analysis was then performed, revealing that the mean rank for each group (baseline 4.33, red 1.88, yellow 4.05, blue 1.39, green 3.35) differed significantly across groups (χ2 = 175.64, p < 0.001). Posterior comparisons indicated significant differences between the baseline and green, red, and blue light (p < 0.001), between yellow light and red and blue light (p < 0.001), and between green light and red and blue light (p < 0.001). Exposure to blue and red light significantly increased alertness compared to baseline, yellow, and green light.
Furthermore, no statistically significant differences in KSS scores were found across different light conditions among age groups. However, a significant gender difference was observed under the blue light condition (Z = −2.485, p = 0.013), with female participants reporting lower KSS scores than male participants. This suggests that women exhibited higher levels of subjective alertness than men when exposed to blue light.

4. Discussion

Landscape lighting plays a critical role in shaping nighttime recreational and leisure experiences. In this study, we investigated the psychophysiological effects of different lighting conditions on human alertness using both subjective evaluations and objective EEG measurements. The findings revealed that different colors of STL produced distinct impacts on brain activity and alertness levels. Each lighting condition elicited different neural responses, indicating that color-specific landscape lighting can differentially influence human cognitive states in nighttime environments. It has been demonstrated that different wavelengths of light influence alertness and modulate the intensity of brainwave activity in an indoor environment [37,42,43,44,45]. Our results demonstrated a significant increase in average beta power when participants were exposed to red and blue colors of STL in an outdoor environment, indicating elevated levels of alertness. Exposure to all four lighting conditions significantly enhanced beta activity, reflecting an overall increase in EEG-based nighttime alertness. These findings suggest that variations in beta wave power, particularly in the frontal and parietal regions, are closely associated with changes in human alertness under different landscape lighting scenarios. The use of photographic simulations in a controlled environment, though not fully replicating real-world experiences, remains a valid approach supported by environmental psychology and cognitive neuroscience for assessing perceptual responses to light stimuli.
The response to different light colors varied significantly across age and gender, especially in indoor environments [46,47,48]. In our study, younger participants exhibited significantly higher beta wave activity in the frontal and parietal lobes under red and blue light exposure, indicating a greater degree of alertness. Additionally, with advancing age, the responsiveness to light-based stimulation diminished, as reflected in the gradual decrease in mean beta power. These findings indicated alertness in response to nocturnal polychromatic light declines with age. Gender differences were also notable, with female participants exhibiting greater alertness than male participants under red and blue lighting.
Participants’ alertness ratings might be psychologically influenced by the perceived color [49]. Red and blue light reduced KSS scores, thereby enhancing alertness [33]. We confirmed that the results of the effects of different light colors on people under landscape lighting conditions are consistent. Based on pre-test and post-test subjective questionnaire ratings of alertness levels, the results provide valuable insights for the design of nighttime landscape lighting. Nighttime lighting environments significantly influenced human alertness, with red and blue light notably increasing alertness levels, as indicated by decreased KSS scores. Moreover, exposure to blue light was associated with subjective ratings of higher alertness in women compared to men, consistent with the EEG results. The duration and intensity of light exposure in this study were not intended to alter circadian rhythms but rather to evoke short-term psychophysiological responses. Although the experimental setting was controlled and static, the use of KSS remains appropriate for capturing transient changes in alertness, as supported by previous short-exposure studies. Nonetheless, future research could incorporate additional physiological markers or longer exposure periods to further examine the circadian impact of colored landscape lighting.
This study compares the effects of red, yellow, blue, and green light from shooting tree lights to better understand the psychological and physiological impacts of different nocturnal landscape lighting conditions, providing valuable guidance for lighting design. Exposure to red and blue light, while significantly enhancing alertness, also contributes to increased fatigue and hinders physical relaxation for viewers [33]. Beta wave activity showed a strong correlation with both EEG measurements and subjective alertness reports, indicating that prolonged exposure to red and blue landscape lighting may significantly influence individual alertness levels. Among the colors of STL, yellow light exhibited the lowest average beta power. Subjective evaluations further supported the calming and stress-reducing effects of yellow lighting, suggesting its suitability for relaxation-oriented environments. Therefore, yellow light should be prioritized in landscape lighting design to effectively reduce physiological arousal, promote psychological relaxation, and enhance overall comfort in nighttime outdoor environment.
This study’s findings should be interpreted within the context of a controlled laboratory setting using simulated environmental visuals. While this method enables the isolation of light color effects and offers high internal validity, it does not fully replicate real-world outdoor nightscape experiences, which involve additional spatial, acoustic, and social cues. Therefore, future studies should incorporate field-based experiments using physical lighting installations and real-time physiological tracking to validate and extend these preliminary findings. In addition, future studies could integrate dynamic lighting simulations with multisensory environmental cues (including auditory, spatial, and social stimuli) to more accurately reflect the complexity of real-world nighttime environments. To reveal the cumulative or circadian effects of repeated light exposure over time.

5. Conclusions

This study explored the psychophysiological effects of different shooting tree light colors through controlled visual simulations. By integrating EEG measurements with subjective alertness ratings, we found that red and blue lighting significantly enhanced beta brainwave activity and perceived alertness, whereas yellow lighting produced the lowest Beta power, indicating a more relaxed physiological state. Additionally, the results revealed individual differences in light sensitivity, younger participants and females exhibited greater responsiveness under red and blue light conditions. This underscores the importance of accounting for demographic variability in non-visual light responses and informs the development of tailored lighting strategies in public space design.
From a theoretical standpoint, the findings reinforce the environmental psychology perspective that ambient sensory stimuli—light colors—can influence cognitive and emotional states, especially under nocturnal conditions where visual inputs play a dominant role. Practically, yellow lighting may be most appropriate for relaxation-oriented green spaces, whereas more stimulating hues like red and blue could be deployed in active or transitional urban zones. Although this study employed photographic simulations in a laboratory setting, the controlled conditions provided a robust foundation for future field-based investigations. Overall, our research contributes to both the theoretical advancement and practical refinement of nighttime landscape lighting, particularly in fostering comfort, perceived safety, and psychological well-being in urban environments. The findings offer practical implications for implementing human-centered lighting strategies in botanical landscapes to enhance relaxation and well-being in urban nighttime public environments.

Author Contributions

Conceptualization, X.W., Y.Z. and Z.L.; Methodology, J.M., Y.Z. and Z.L.; Software, J.M.; Validation, Y.Z.; Formal analysis, Z.L.; Investigation, Y.Z. and Z.L.; Data curation, J.M.; Writing—original draft, J.M.; Writing—review & editing, X.W.; Visualization, J.M.; Supervision, X.W.; Project administration, X.W. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.

Conflicts of Interest

The authors declare no conflict of interest.

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Buildings 15 02907 g001
Figure 1. Flowchart of experimental design.
Figure 1. Flowchart of experimental design.
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Figure 2. Beta power differences between four different colors of shooting tree lights. * p < 0.05, ** p < 0.01, *** p < 0.001.
Figure 2. Beta power differences between four different colors of shooting tree lights. * p < 0.05, ** p < 0.01, *** p < 0.001.
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Figure 3. Differences in mean beta power at different ages. * p < 0.05.
Figure 3. Differences in mean beta power at different ages. * p < 0.05.
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Figure 4. Effect of different genders on mean beta power. * p < 0.05.
Figure 4. Effect of different genders on mean beta power. * p < 0.05.
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Figure 5. Differential scores of nighttime KSS alertness responses.
Figure 5. Differential scores of nighttime KSS alertness responses.
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Table 1. Participant information (statistical information on the age of different types of people).
Table 1. Participant information (statistical information on the age of different types of people).
ParticipantsAge (Mean ± SD)Gender (Mean ± SD)Number
60Youth (20.9 ± 0.47)Male (22.3 ± 1.56)10
Female (19.5 ± 1.65)10
Middle-aged (41.1 ± 0.67)Male (41.4 ± 2.98)10
Female (40.8 ± 3.15)10
Old (61.25 ± 1.09)Male (63.9 ± 3.17)10
Female (58.6 ± 5.01)10
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MDPI and ACS Style

Wang, X.; Mo, J.; Zhou, Y.; Long, Z. Psychophysiological Effects of Shooting Tree Light Colors on Alertness: A Controlled Laboratory Study. Buildings 2025, 15, 2907. https://doi.org/10.3390/buildings15162907

AMA Style

Wang X, Mo J, Zhou Y, Long Z. Psychophysiological Effects of Shooting Tree Light Colors on Alertness: A Controlled Laboratory Study. Buildings. 2025; 15(16):2907. https://doi.org/10.3390/buildings15162907

Chicago/Turabian Style

Wang, Xudong, Jiali Mo, Yuqi Zhou, and Ziyu Long. 2025. "Psychophysiological Effects of Shooting Tree Light Colors on Alertness: A Controlled Laboratory Study" Buildings 15, no. 16: 2907. https://doi.org/10.3390/buildings15162907

APA Style

Wang, X., Mo, J., Zhou, Y., & Long, Z. (2025). Psychophysiological Effects of Shooting Tree Light Colors on Alertness: A Controlled Laboratory Study. Buildings, 15(16), 2907. https://doi.org/10.3390/buildings15162907

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