Light correlated color temperature and task switching performance in preschool-age children: Preliminary insights

Improving children's alertness and neuromuscular response by using a blue-enriched white light in the kindergarten playroom

Preschool children, who spend most of their time indoors, and the effects of artificial light on children's health and performance are important. Previous studies show that blue-enriched white light (BWL) has significant effects on human bodies, but only a few studies have specifically examined its effects in young children. Moreover, due to the significant physiological differences between children and adults, findings from BWL studies in adults cannot be directly applied to children. Therefore, investigating the effects of BWL on young children living in indoor environments is crucial. We recruited 24 preschool children (age: 5 ± 0.8 years; 12 girls and 12 boys) to participate in a within-subject, randomized crossover study involving common white light (CWL) (450 lx, Melanopic EDI: 354.04 lx) and BWL (450 lx, Melanopic EDI: 746.05 lx) in a kindergarten playroom. Under different light conditions, the children underwent tests for cardiac activity and critical flicker fusion frequency (CFF), as well as psychomotor vigilance task (PVT) and ruler drop test (RDT). The results indicated that BWL had significant effects on preschool children. Compared to CWL exposure, BWL exposure significantly improved cardiac activity, alertness, and neuromuscular response but slightly increased visual fatigue. Our study reveals that BWL has significant potential to improve children's physiological and cognitive functions, particularly to improve cardiac activity, alertness, and neuromuscular response. This study broadens the understanding of the effects of indoor lighting on children and provides a theoretical basis for designing a healthy indoor environment for children.

The Circadian Response to Evening Light Spectra in Early Childhood: Preliminary Insights

Although the sensitivity of the circadian system to the characteristics of light (e.g., biological timing, intensity, duration, spectrum) has been well studied in adults, data in early childhood remain limited. Utilizing a crossover, within-subjects design, we examined differences in the circadian response to evening light exposure at two different correlated color temperatures (CCT) in preschool-aged children. Healthy, good sleeping children (n = 10, 3.0-5.9 years) completed two 10-day protocols. In each protocol, after maintaining a stable sleep schedule for 7 days, a 3-day in-home dim-light circadian assessment was performed. On the first and third evenings of the in-home protocol, dim-light melatonin onset (DLMO) was assessed. On the second evening, children received a 1-h light exposure of 20 lux from either 2700 K (low CCT) or 5000 K (high CCT) (~9 and ~16 melanopic equivalent daylight illuminance (mEDI lux), respectively) centered around their habitual bedtime. Children received the remaining light condition during their second protocol, with the order counterbalanced across participants. Salivary melatonin was collected to compute melatonin suppression and circadian phase shift resulting from each experimental light condition. Melatonin suppression across the 1-h light stimulus was significantly greater during exposure to the high CCT light (M = 56.3%, SD = 19.25%) than during the low CCT light (M = 23.90%, SD = 41.06%). Both light conditions resulted in marked delays of circadian timing, but only a small difference (d = -0.25) was observed in the delay between the 5000 K (M = 35.3 min, SD = 34.3 min) and 2700 K (M = 26.7 min, SD = 15.9 min) conditions. Together, these findings add to a growing literature demonstrating high responsivity of the circadian clock to evening light exposure in early childhood and provide preliminary evidence of melatonin suppression sensitivity to differences in light spectrum in preschool-aged children.

Diurnal biological effects of correlated colour temperature and its exposure timing on alertness, cognition, and mood in an enclosed environment

Artificial lighting, which profits from the non-visual effects of light, is a potentially promising solution to support residents' psychophysiological health and performance at specific times of the day in enclosed environments. However, few studies have investigated the non-visual effects of daytime correlated colour temperature (CCT) and its exposure timing on human alertness, cognition, and mood. However, the neural mechanisms underlying these effects are largely unknown. The current study evaluated the effects of daytime CCT and its exposure timing on markers of subjective experience, cognitive performance, and cerebral activity in a simulated enclosed environment. Forty-two participants participated a single-blind laboratory study with a 4 within (CCT: 4000 K vs. 6500 K vs. 8500 K vs. 12,000 K) × 2 between (exposure timing: morning vs. afternoon) mixed design. The results showed time of the day dependent benefits of the daytime CCT on subjective experience, vigilant attention, response inhibition, working memory, emotional perception, and risk decisions. The results of the electroencephalogram (EEG) revealed that lower-frequency EEG bands, including theta, alpha, and alpha-theta, were quite sensitive to daytime CCT intervention, which provides a valuable reference for trying to establish the underlying mechanisms that support the performance-enhancement effects of exposure to CCT in the daytime. However, the results revealed no consistent intervention pattern across these measurements. Therefore, future studies should consider personalised optimisation of daytime CCT for different cognitive demands.

The cognitive impact of light: illuminating ipRGC circuit mechanisms

Ever-present in our environments, light entrains circadian rhythms over long timescales, influencing daily activity patterns, health and performance. Increasing evidence indicates that light also acts independently of the circadian system to directly impact physiology and behaviour, including cognition. Exposure to light stimulates brain areas involved in cognition and appears to improve a broad range of cognitive functions. However, the extent of these effects and their mechanisms are unknown. Intrinsically photosensitive retinal ganglion cells (ipRGCs) have emerged as the primary conduit through which light impacts non-image-forming behaviours and are a prime candidate for mediating the direct effects of light on cognition. Here, we review the current state of understanding of these effects in humans and mice, and the tools available to uncover circuit-level and photoreceptor-specific mechanisms. We also address current barriers to progress in this area. Current and future efforts to unravel the circuits through which light influences cognitive functions may inform the tailoring of lighting landscapes to optimize health and cognitive function.

Uncovering placemaking needs with(in) a kindergarten community: a cross-disciplinary approach to participatory design

Introduction

The design of early childhood education and care facilities faces the double challenge of creating a stimulating environment for young children and a supportive workplace for staff. The existing body of research suggests that placemaking strategies serve both requirements. A promising approach to meet placemaking needs is the participation of future occupants in the building design.

Methods

We pursued a participatory design study with the community of an Austrian kindergarten aiming to inform the future building renovation. We combined novel cultural fiction probes methods with conventional inquiry methods to gather information from children and teachers about their experience of the built environment. Using thematic and content analyzes we explored placemaking needs from different epistemic perspectives and converged findings through iterative exchange.

Results

Returns of children and teachers were interconnected and complementary. From a design-oriented perspective, children's experience of place was relatable to spatial, temporo-spatial, and acoustic qualities as well as control needs. From a human-centered perspective, teachers' experience of place was relatable to the needs of feeling embedded, protected, enacted, and socially connected. The converged findings revealed dynamic placemaking processes involving the elements of space, time, and control at different levels.

Discussion

Cross-disciplinary collaboration and research consolidation brought forth valuable insights on supportive structures for both children and teachers, facilitated timely knowledge transfer, and converted into design solutions that foster enacted placemaking. Albeit general transferability is limited, findings are interpretable within a solid framework of existing theories, concepts and evidence.

Emotional responses of college students to filtered fluorescent lighting in a classroom (v3)

Background

Classroom lighting, usually bright fluorescent light, can significantly influence the learning environment and emotions of students.

Objective

To assess the emotional impact of classroom lighting on students during an academic year.

Methods

This study used an ABAB withdrawal research design in the following manner: in phase A, the baseline condition, classroom lighting was provided by conventional overhead white fluorescent classroom lights; in phase B, the intervention condition, the conventional overhead white fluorescent classroom lights were covered with fabric filters (thin, translucent, creamy-colored plastic sheets) that were attached to the lighting fixture frame with magnetic discs. The filters produced softer light in the classroom than the fluorescent lights. Each phase lasted for at least 2 weeks. During each phase, students rated 18 pairs of words from the Mehrabian and Russell pleasure, arousal, and dominance semantic differential scale at least four times to assess the emotional impact of the lighting conditions.

Results

For all three emotional behaviors, the mean score of the filtered fluorescent light phase was significantly greater than the mean score of the baseline unfiltered fluorescent lighting phase, indicating more positive emotional responses. Students also noted they experienced fewer headaches and found it easier to see the whiteboard at the front of the classroom when the light filters were in place.

Conclusion

The light filters exerted a positive impact on the students' emotions. Students preferred the filtered lighting to fluorescent lighting. This study supports the installation of filters over fluorescent lights in a college classroom.